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G3+, G7+, 6+, Glu, Crea Cartridges
The i-STAT Portable Clinical Analyzer, in conjunction with the i-stat Test Cartridges,
performs blood analysis at the point of care. Just 2-3 drops of fresh whole blood is all that is
required, and the portable, battery-powered analyzer displays quantitative test results in
approximately 2 minutes. Portable printers and infrared communication devices allow all
patient information obtained at the bedside to be printed on demand and transmitted to
centralized information systems for record keeping and billing.
Quantitative determination of Sodium (Na+), Potassium (K+), Chloride (Cl-), Glucose (Glu),
Urea Nitrogen (BUN), and Hematocrit(Hct) in whole blood is performed using the
6+cartridge. Hemoglobin is mathematically derived based on the hematocrit value. The 6+
cartridge is used in the ED, CCU, ICU, OR, and the CATH Lab.
The G cartridge for glucose only is used in the OR and the CATH LAB, for patients with
glucose >200 mg/dL and Hematocrit <25 %.
Quantitative determination of Creatinine is performed using the Creatinine cartridge in
the ED and Radiology.
Arterial Blood Gas testing is performed using the EG7+ cartridge in the ED, ICU, CCU, SCN,
OR, PACU, and the CATH LAB. The parameters that may be measured are: Sodium(Na),
Potassium(K), Ionized calcium(iCa), pH, pCO2, pO2,and HCT. TCO2, HCO3, BE, sO2 and
Hemoglobin are calculated results.
Arterial Blood Gas testing is performed using the G3+ cartridge in the Emergency
Department, SCN CCU, ICU, OR, the CATH LAB and on the patient service/ nursing units.
The parameters that may be measured are: pH, pCO2,and pO2. TCO2, HCO3, BE, and sO2
are calculated results.
i-STAT orders
All i-STAT orders must be written on the patient’s chart. DO NOT PERFORM
patient’s chart for anticoagulant therapy or diagnosis which would indicate the
necessity for increasing the pressure holding time on the puncture site.
Patient Preparation:
-Verify patient identification by checking the patient’s name and social security
number and/or patient account number on the arm band.
-Explain the purpose of the test and the steps of the procedure to the patient
prior to performing the test.
-The operator’s hands must be washed before and after testing.
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-Because of the hazardous nature of handling blood products, it is required that
disposable latex gloves or an acceptable substitute be used when collecting specimens
and test procedures. Standard precautions shall be observed for all blood specimens
and they should be handled at Biosafety Level 2 as recommended for any potentially
infectious material in the Centers for Disease Control/National Institutes of Health
manual, Biosafety in Microbiological and Biomedical Laboratories, 1988 or in the
National Committee for Clinical Laboratory Standard Document M29, Protection of
Laboratory Workers from Infectious Disease Transmitted by Blood, Body Fluids, and
Tissue, 1991.
Sample volume (size): 65 uL for 6+ and G, cartridges
95 uL for EG7+,G3+, and Crea cartridges
Sample Type: Fresh whole blood from venous, arterial puncture, skin, or indwelling line.
Observe the following precautions:
-Avoid drawing from an arm with an IV line. IV solutions will dilute the
sample and may interfere with the tests.
-Avoid localized stasis which can increase potassium and pH results and
decrease ionized calcium results. If a tourniquet is applied for more than one
minute while looking for a vein, release and reapply after two to three
-Allow the tourniquet to remain in place until all blood is withdrawn to prevent
changes in ionized calcium and pH results.
-Avoid extra muscle activity, such as clenching and unclenching the fist, which
may increase potassium results.
-Avoid hemolysis by allowing residual alcohol to dry over the puncture site.
Hemolysis will cause an increase in potassium results and a decrease in
calcium results.
-If the cartridge cannot be filled immediately, collect a sample into an evacuated
blood collection tube or a syringe containing heparin ( sodium, lithium or
balanced) anticoagulant. For ionized calcium measurements, balanced
heparin or <10 IU/ml of sodium or lithium heparin is recommended.
Balanced heparin or low volume heparin is used in some commercially
available blood gas syringes. Becton-Dickenson’s lithium heparin
evacuated tubes contain approximately 15 IU/ml when filled to capacity.
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-Fill evacuated tubes and syringes with anticoagulant to capacity. Incomplete
filling will cause higher heparin to blood ratios which will decrease
ionized calcium results and may affect other results.
-Gently mix blood and anticoagulant immediately to avoid clotting: invert an
evacuated tube 5 to 10 times and roll a syringe between the palms for at
least five seconds in two directions.
-Collect vacuum tubes in the prescribed sequence to avoid interference due to
carry over of anticoagulant from one tube to the next: blue, red, gold, green,
lavender, grey. If a blue stoppered tube is drawn, draw a 1 ml blue
stoppered discard tube before drawing the blue stoppered tube.
-For the most accurate results, test samples immediately after draw. If testing is
delayed, remix evacuated tubes by gentle inversion and syringes by rolling
between the palms for 5 seconds. Test samples within 10 minutes after
Arterial :
Observe the following precautions:
-Evacuated tubes are not recommended for blood gas analysis.
-Follow the directions carefully when using pre-prepared blood gas kits and
syringes. Fill syringes to the recommended capacity or use the least
amount of liquid heparin anticoagulant that will prevent clotting.
Under filling syringes which contain liquid heparin will decrease results
due to dilution and will decrease ionized calcium results due to binding.
-For ionized calcium, use balanced or low volume heparin blood gas syringes.
-Wait 15 minutes before specimen collection when there has been a change in
ventilator setting or the FIO2.
-Mix blood and anticoagulant by rolling between the palms for at least 5
seconds. Then invert the syringe repeatedly for at least 5 seconds.
-Do not expose the sample to air when testing for ionized calcium , pH, pCO2
or pO2.
-Avoid or remove immediately any air drawn into the syringe and maintain
anaerobic conditions.
-For the most accurate results, test samples immediately after draw. If testing is
delayed, remix. Test samples within 10 minutes.
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-Fill the cartridge before icing the sample for transportation. Icing will
increase potassium and will affect oxygen levels in samples collected in plastic
In-Dwelling Line :
Follow the following precautions:
-Withdraw slowly three to six times the volume of the catheter, connectors, and
needle to remove intravenous solution, heparin, or medications that may
contaminate the sample. Samples collected without anticoagulant should be
tested within 3 minutes. Samples collected in lithium heparin syringes should
tested within 10 minutes and well mixed before use.
Collection Options:
Evacuated tubes (for Venous samples only)
-without anticoagulant
-with lithium heparin anticoagulant).
Venous samples :
-without anticoagulant
-with lithium heparin anticoagulant
Arterial samples:
-balanced or low heparin
-Blood Gas Syringe Kit
Test Within Time Frames:
3 minutes
-evacuated tubes or syringes without anticoagulant
10 minutes
-for evacuated tubes or syringes with anticoagulant
(Maintain anaerobic conditions when using syringes) (Evacuated tubes and
syringes must be well mixed before testing)
Handling Conditions
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If the i-STAT cartridge is not filled immediately after collection, the blood must be
thoroughly mixed. Mix tubes by gentle inversion 7 times. Mix syringes by rolling
between the palms 5 times in three directions.
Criteria For Specimen Rejection
-Evidence of clotting.
-Specimens collected in anticoagulant other than lithium heparin.
-Syringe for pH, PCO2, and PO2 with air bubbles in sample.
-Other sample types such as urine, CSF and pleural fluid.
-Samples not collected according to the specimen type precaution guidelines.
Sample Transfer Device
Blunt End Dispensers
-To avoid the use of needles when transferring a blood sample from an evacuated
tube, a dispenser can be used. Do not use dispensers because that would introduce air
into the sample when ionized calcium, pH or pCO2 are being measured.
Specimen Labeling
Unless the specimen is analyzed immediately after collection and then discarded, the
specimen container must be labeled with the following information.
-Patient's name
-Patient's social security number
-Time and date of collection
-Phlebotomist/collector ID
III. Reagent and Supplies
Test Cartridges
The i-STAT Test Cartridge is a self contained testing system. Each cartridge is
considered a "run", with no reuse of reagents or carry-over of specimen.
The 6+ cartridge contains the following tests:
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Hemoglobin (calculated)
The Arterial Blood Gas Cartridge, EG7+, performs the following tests:
Ionized Calcium
HCO3 (calculated)
TCO2 (calculated)
BE (calculated)
sO2 (calculated)
Hemoglobin (calculated)
The Arterial Blood Gas Cartridge, G3+, performs the following tests:
HCO3 (calculated)
TCO2 (calculated)
BE (calculated)
sO2 (calculated)
The Glucose cartridge performs only glucose.
The Creatinine cartridge performs only creatinine.
Each i-STAT Test Cartridge contains a buffered calibrant containing known
concentrations of each analyte; a sample handing system; an array of unauthorized
sensors; and conductive pads to make electrical contact with the analyzer. The
sensors are electrodes which are micro-fabricated onto silicon chips. Sensing
functionality is imparted to the electrodes by coating of chemically sensitive films
such as ion-selective membranes and enzyme layers. Each sensor is connected to a
contact pad by a signal line.
Reagent Storage
Test cartridges are stored in their sealed foil pouches at 2-8o C. Do not allow the
cartridge to freeze. Cartridges are usable until the expiration date printed on the foil
pouch if stored at 2-8o C.
Cartridges may be stored at room temperature (18-30o) for a maximum of fourteen
(14) days. If the cartridges are stored at room temperature, use the calendar on the
cartridge box to indicate the room temperature expiration date. Do not use the
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cartridges if the 14 day time has expired. Do not store cartridges at temperatures
exceeding 30oC.
6+ and Glucose cartridges do not require thermal control and may be used after
standing just 5 minutes at room temperature. An entire box should stand at room
temperature for one hour.
EG7+ and G3+,and Creatinine cartridges require thermal control (37
) and may be
used after standing just 5 minutes at room temperature. An entire box should stand at
room temperature for one hour.
HAVE COME TO ROOM TEMPERATURE. Cartridges must be used
immediately after they have been removed from the foil pouch.
i-STAT System Components
Blood Collection Supplies
Portable Clinical Analyzer
Electronic Simulator
Reagent Cartridge
Printer (hand held)
IR Interface Cradle
Disposables (as appropriate for sample application)
2 x 2 Gauze
Alcohol Pads
Venipuncture Supplies (Needles, Syringes)
Vacutainer Tubes (Lithium Heparin)
Arterial Blood Gas Supplies (Needles, Syringes, low
volume heparin blood gas syringes
Quality Control
Calibration and Linearity
Calibration is performed internally each time a test cartridge is inserted into the
i-STAT analyzer with no intervention required on the part of the operator. Each
cartridge includes a sealed foil pack which contains a calibrant solution with a known
concentration of each analyte. During the first part of the testing cycle the calibrator
is automatically forced out of the foil pack and over the sensors. The signals
produced by the sensors in response to the calibrant solution are stored. If the
calibration fails, the i-STAT analyzer will give a code and results will not be
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Calibration verification is performed by the Laboratory Department every six months.
Linearity is performed by the Laboratory Department initially on each analyte
Quality Control
Quality control (QC) is the process designed to ensure that a test system is working
properly. The i-STAT system daily quality control is an electronic simulator. Liquid
control and calibration verification solutions for verification of cartridges are tested by
the laboratory for each new lot number of cartridges received.
Electronic Simulator
a. External Electronic Simulator
The Electronic Simulator is a stable electronic device which
verifies the electrical measurement circuits by producing signals at
two levels to check the accuracy and integrity of the circuits and
the electrical isolation between individual measurement channels.
The results of the Electronic Simulator are "PASS" or "FAIL".
External Electronic Simulator is used to verify a failed internal
simulator test.
Remove the external Electronic Simulator from storage.
Insert the external Electronic Simulator into the cartridge
door to the i-STAT instrument. CONTRACTING
CARTRIDGES will be displayed.
Wait 70 seconds. PASS or FAIL will be displayed at the end
of the simulator test. The acceptable limits for the simulator
are set internally; FAIL will be displayed if the limits are
If PASS is displayed, patient testing may be initiated.
If FAIL is displayed on the analyzer screen: Repeat the
procedure with the same external Electronic Simulator. If
PASS is displayed use the analyzer as required. If FAIL is
displayed repeat the procedure with a different external
Electronic Simulator.
If PASS is displayed with the second external Electronic
Simulator: Use the analyzer as required. Deliver the
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questionable external Electronic Simulator to the Laboratory
If FAIL is DISPLAYED with the second external Electronic
Simulator: DO NOT analyze patient samples with the
analyzer. Transmit the results to the Central Data Station.
Deliver the faulty analyzer to the laboratory. The Point of
Care Coordinator will record the failure along with the action
Remove the external Electronic Simulator after the locked
message “LCK” is no longer displayed and return to
The results of the external Electronic Simulator, the date,
time and operator ID will be transmitted by a Respiratory
Therapist to the Central Data Station via the infrared cradle
for review and record keeping. Radiology and the CATH
LAB will transmit their i-STAT analyzer each day at the end
of 1st shift.
Perform the Electronic QC in the following situations:
When an internal Electronic Simulator fails.
When an analyzer is brought from a cold
environment to a hot, humid environment to insure
that any moisture that may have condensed on the
internal connector has evaporated before performing
patient tests.
When the analyzer's batteries are changed.
Internal Electronic Simulator
The internal Electronic Simulator is selected on an 8/24 hour
schedule. The internal Electronic Simulator will run every 8
hours for pH, pCO2, pO2, hematocrit and ACT channels and
every 24 hours for all other channels.
QC Lockout is enabled on all analyzers. This setting
prevents analyzers from running a cartridge after a failed
internal Electronic Simulator test.
An internal Electronic Simulator is a circuit in the Analyzer which verifies the performance
of each Analyzer by testing signals consistent with both very low and very high
concentrations of each of the analytes. The software in the analyzer and module measure
these signals as it would measure signals from a cartridge. The software checks the
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measurements against predetermined thresholds and indicates their acceptability to the use
via a PASS/FAIL message. ACT analyte has quality control tested every 8 hours.
The internal Electronic Simulator is triggered by inserting a cartridge.
If the software detects that the specified time has elapsed since the
last Electronic Simulator test (internal or external), it will
automatically perform the internal test before the sample is tested,
adding about 15-20 seconds to the testing cycle. A failed Simulator
test stops the cycle, the FAIL simulator result will be displayed on the
screen, and the sample will not be analyzed. If the test passes, the
cartridge cycle continues to completion and the cartridge results are
What to do if the Electronic Simulator Fails:
Rerun the cartridge in the same Analyzer to ensure the FAIL was not
due to a one-time spike of electrical noise. If the test fails again,
rerun the cartridge in another Analyzer if immediately available.
Note that the cartridge should not be run if there is more than a three
minute delay from the time it is filled. If the cartridge fails in more
than one Analyzer, use another cartridge. In all cases, an external
Electronic Simulator can be used to verify proper performance of
Analyzer. Failed analyzers are to be brought to the laboratory for
Verification of Cartridges
Verification of newly received cartridges (performed by the
Laboratory Department)
Verify that the transit temperatures of each shipment were
satisfactory using the four window temperature indicator strip
affixed to the cartridge box.
From each lot of cartridges received, analyze three levels of
i-STAT and Meter Trax Controls each in duplicate, using any
verified analyzer.
From each new lot number of cartridges received, analyze
i-STAT calibration verification solutions one, three, and five
to ensure that patient reference ranges (or reportable ranges)
are acceptable from lot to lot. Hematocrit calibration
verification is performed as a separate procedure at a
minimum every 6 months (see i-STAT Calibration
Verification Procedure).
Perform a parallel reagent check by comparing the quality
calibration verification ranges from the previous lot numbers.
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Perform QC on the old cartridge lot number along with the
new cartridge lot number and record results.
Storage Conditions
Refrigerated Cartridges
Verify that the cartridges stored in the designated
Chemistry refrigerator are all within the expiration
date printed on the boxes. Deliver any expired
cartridges to the Laboratory Point of Care office.
Verify that the Chemistry refrigerator did not exceed
the limits of 2-8oC (25-46oF).
Chemistry will document the refrigerator temperature
If the temperature of the cartridge storage refrigerator
is within the range of 2-8oC (35-46oF) use cartridges
as required.
If the temperature is outside the range of 2-8oC (2546oF) quarantine the cartridges in the storage
refrigerator. Notify the Point of Care Coordinator,
Laboratory Manager, or Supervisor immediately.
DO NOT USE the cartridges from the out-of-control
refrigerator. Record the QC failure with the action
taken via a Laboratory Incident report form.
Room Temperature Cartridges
Verify that all boxes of cartridges at room
temperature have been out of the refrigerator less
than two weeks. Deliver any expired cartridges to
the Laboratory Point of Care office.
If the measured temperature of the room has been
continuously below 30oC (86oF) use cartridges as
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If the measured room temperature has exceeded 30o
(86oF) for any period of time: Quarantine the
cartridges. Notify the Laboratory Point of Care
Coordinator, Laboratory Manager, or Supervisor
immediately. DO NOT use the cartridges. Record
the out of control event and the action taken via a
Laboratory Incident report form.
Comparison of test methods for Sodium, Potassium, Chloride, BUN, Glucose,
Hematocrit, and Creatinine is performed by the Laboratory Point of Care office every
6 months. (See Comparison of Test Methods procedure).
Proficiency Testing is performed on 6+, Creatinine and EG7+ cartridge using CAP’s
AQ2 Survey. Laboratory Point of Care performs 6+ proficiency testing and
Respiratory Therapy performs EG7+ proficiency testing. Proficiency testing samples
are shipped three times during the year and include five challenges for each analyte or
test. Samples are tested exactly like patient samples and the results are returned to
CAP within 10 working days of receipt for grading.
If any QC result is not within range, take corrective action before any patient samples
are tested.
Repeat the test.
If QC is within range, patient testing may proceed.
If QC is not within range, DO NOT PERFORM PATIENT TESTING.
The Point of Care Coordinator will notify i-STAT Technical Service.
Corrective action taken is recorded in the i-STAT Central Data Station and noted on
the i-STAT System QC Log.
Select the Cartridge to be used.
6+ Cartridge is used for stat Electrolytes, BUN, Glucose, and Hematocrit testing
in ED, CCU, ICU, OR and the CATH Lab..
Creatinine cartridge is used for stat Creatinine in ED and Radiology.
EG7+ Cartridge is used for ABG in Critical Care areas: ED, ICU, CCU, SCN, OR,
PACU, and the CATH LAB..
G3+ Cartridge is used for ABG in SCN, ED, ICU, CCU, OR, PACU,the CATH LAB
and on nursing floors/patient care units.
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Glucose Cartridge is used in the Operating Room, and CATH LAB for patients with
glucose concentrations above 200 mg/d and hematocrits below 25%.
The cartridge should be handled as follows to avoid difficulty in filling or
rejection by the analyzer:
-Do not contaminate the contact pads with finger prints or talc from gloves as the
analyzer may not be able to make proper contact with the cartridge.
-Do not exert excessive pressure over the central area of the label as the calibrant
pack underneath could burst prematurely.
-Do not block the air vent as the sample will not be able to flow to the fill mark
and the calibrant solution will not be able to flow to the sensors.
-Do not use a cartridge on which blood or any other fluid is spilled, as the
analyzer’s connector may be contaminated.
Fill Test Cartridge
Remove the cartridge from the protective foil pouch after it has come to room
Place cartridge on a flat surface or hold it horizontally. Do not hold cartridge
between the fingers if using a syringe with needle to fill the sample well.
Collect the blood specimen.
Direct the pipette tip, capillary tube, or needle into the sample well.
Dispense sample slowly and steadily until it reaches the FILL TO mark (tilt
cartridge slightly if necessary). Avoid the introduction of air bubbles into the
sample well.
Fill the sample well 1/3 to 2/3 full.
Once the cartridge is full, complete the procedure without delay.
Seal Test Cartridge
Fold the plastic snap closure over the sample well.
Press on the rounded end of the closure until it snaps into place.
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Failure to seal the cartridge will prevent patient testing.
Insert Test Cartridge into the i-STAT Analyzer
Hold the analyzer firmly in one hand. Grasp the test cartridge by the sides,
label facing up, with the other hand.
Push the cartridge slowly and smoothly through the cartridge door until it will
go no further.
The cartridge activates the analyzer. The analyzer displays "CONTACTING
CARTRIDGE" then a time-to-result bar, the cartridge type, "LCK" prompt,
and an area in which to enter operator and patient identification numbers.
Do not attempt to remove a test cartridge while the "LCK" prompt is
displayed indicating that the cartridge should not be removed. The force
necessary to remove the cartridge would damage the analyzer and invalidate
the results.
Enter Identification Numbers
Enter your assigned operator identification number. Respiratory Therapists
use your LIS numerical Tech Code. All other operators use the first 6 digits
of your social security number. Use the numerical keypad to enter the
number. Press the "CLR" key to backspace and erase a wrong number. Press
the "ENT" key to enter the completed number.
After the ENT key is pressed, the prompt "Repeat #, ENT" appears in the box.
Repeat the operator identification number as above and press ENT to signal
the analyzer that the last digit has been entered.
Enter the patient's account number, not the patient social security number, in
the same manner as the operator ID number.
If either the operator identification or the patient identification numbers are
not entered correctly in duplicate, the message "ID DID NOT MATCH
START AGAIN" will display. Re-enter the ID number that was in error.
Operating rooms and “codes” present a unique testing situation in that tests are
run repeatedly on the same patient. Pressing the DIS key when
for Patient ID will recall the last Patient ID entered into the analyzer. The
repeat request for Patient ID may also be entered by pressing the Display key.
Enter Blood Gas and Patient Information
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After the patient identification number is entered, the PAGE key is activated allowing
access to an additional data entry screen. (If results are already displayed, press the
PAGE key twice to access the data entry screen).
The cursor will be flashing at the first input area. Use the numbered keys to input
information and press the ENT key to advance to the next input area (or to return to
the first area from the last input area). Invalid numbers will be ignored, and incorrect
inputs can be corrected using the CLR key as a backspace.
Pt Temp
Enter the patient’s temperature in degrees Fahrenheit or Centigrade.
Use the * key to enter a decimal point. The analyzer will interpret
numbers between 50.0 and 110.0 as degrees Fahrenheit and
between10.0 and 45.0 as degrees Centigrade.
Enter the FIO2 value as a whole number from 0 to 100,
representing the number of liters or a percentage of the
oxygen the patient is receiving. Use the * key to enter a decimal
Free Field 1:(6 spaces)
Delivery System:(1 space)
0= room air
1= nasal can
2= fac tent
3= hood
5= trach
6= mask
7= vent
8= croup tent
Free Field 2: (5 spaces)
Mode:(1 space)
Rate:(2 spaces)
1= AC
2= SIMV if RR<10 use a 0
3= CPAP to precede #
4= P/C
PS:(2 spaces)
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Tidal Volume (3 spaces)
PEEP (2 spaces)
Free Field 3: (4 spaces)
Collection Site
1= R Rad
Drawn By
Allens Test
2= L Rad
MD Notified
1= operator
1= yes
2= no
2= no
3= R Brach
4= L Brach
4= MD
5= R Fem
6= L Fem
7= art line
8= UAC
9= UVC
Sample TYPE
Enter the number corresponding to the sample type:
1 ART(arterial)
2 VEN (venous)
MXVN(mixed venous)
When 6(CPB) is chosen as the sample type, a special algorithm for hematocrit
values is used. The algorithm infers a total protein level, assuming the pump
priming solution dilutes the hematocrit and total protein equally. An adjusted
hematocrit value is reported Hct,CPB on both the analyzer display and printout.
After data entry is completed the free fields may be edited until the results are printed
or transmitted to the Central Data Station or until a new cartridge or external
Electronic Simulator is run.
View Results
The Portable Clinical Analyzer will display test results once the cartridge has been
unlocked and the LCK prompt disappears. Results will be displayed for 45 seconds .
Results can be recalled to the display screen by pressing the display key.
Results should either be transcribed onto the patient’s medical record or
transmitted to the portable printer or the Central Data Station
Remove the Test Cartridge
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Remove the cartridge any time after the "LCK" prompt disappears from the
display screen. Discard the cartridge in an appropriate Biohazard Waste
The analyzer display will deactivate after 45 seconds to save the battery. The last
results can be recalled by pushing "DISPLAY".
Once a cartridge is removed, even if results are still displayed, the analyzer is
ready to accept another cartridge.
The i-STAT Portable Clinical Analyzer contains a microprocessor that performs all
calculations required for reportable results.
Reporting Results
The i-STAT Analyzer will produce an audible beep as soon as the results are displayed. The
results are displayed in numerical and bar graph forms. Results may be recorded on the
patient's chart directly from the i-STAT LED display or printed and the printout placed on the
patient's chart until the patient's laboratory cumulative summary is charted. The i-STAT will
accumulate a total of 50 test records (patients, control material, and electronic simulator tests).
All information will be transmitted to the Central Data Station, located in the Laboratory, via
the IR Cradle.
Test results are displayed showing numerical concentration values. Bar graphs which depict
the values in relation to reference ranges are also displayed. Blood gas results are not
displayed with reference ranges. The reference range is marked on the bar by tick marks.
When all test values are within their reference ranges, the tick marks will be
aligned. The bar graphs can be used as a visual cue for distinguishing between “normal” and
“abnormal” results.
The reportable range for i-STAT constituents are as follows:
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Hgb (calculated)
Base Excess/BE
Result Out of Reportable (Linear) Range:
If a "<" or ">" sign precedes a value or if a "< >" sign is displayed, the
value exceeded the linear range of measurement for that particular test.
Report the “< or >” result immediately to the patient’s attending physician
or nurse. 6+cartridge results must be repeated by laboratory analysis.
A lithium heparin (green stoppered) tube must be collected for Electrolyte,
BUN , and Glucose verification. An EDTA (lavender stoppered) tube must
be collected for Hematocrit verification. The test to be repeated must be
ordered in SMS as STAT. The patient will be credited by Laboratory Point
of Care for all verification repeats.
Results Displayed
Test results are displayed in numerical concentrations and on the bar graph.
Results are direct readout; no calculation is necessary. There are four
exceptions to the direct readout when the results are not reportable:
Uncharacteristic Results
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[****] is displayed in place of one or more results when a signal from
a sensor is uncharacteristic. This may be due to a defective sensor or
an interferant in the sample. If [****] is displayed repeat the test with
a fresh cartridge. If [****] is still displayed on the 6+cartridge result,
the physician may request a repeat by laboratory analysis. Follow
steps VIII, A, 2 for repeating an i-STAT result by laboratory analysis.
Results Out of Reportable (Linear) Range
See above section on Linearity.
Results Which Exceed Critical Limits (Alert Values)
Results which exceed the laboratory established "Alert
Values" represent an emergency condition.
If critical test result for venous Electrolytes or Hematocrit is
within the i-STAT Analyzer's reportable range repeat the test
for verification with a fresh test cartridge and report the
Glucose >350 mg/dL must be verified by repeat in the
laboratory except for OR patients. The physician will
determine if repeat verification is to be done. Follow step
VIII, A,2 for repeating an i-STAT result by laboratory
ABG alert values are NOT repeated. Arterial
electrolytes, ionized Calcium, and Hematocrit are NOT
All results which exceed Critical Limits must be brought to
the physician or RN responsible’s attention immediately
either by phone call or direction notification. Physician or
RN notification of the Alert Value must be documented on
the patient's chart. Respiratory Therapists will give all results
directly to the physician or RN. Physician/RN notification is
entered into the i-STAT analyzer and reported on the ABG
patient report.
Alert values repeated by i-STAT only will have a Critical
Value Documentation Verification form sent to the nurse
manager or designee. The form must be completed and
returned to Laboratory Point of Care.
The established Alert Values are as follows:
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Any neonate glucose result below 45 mg/dL or above 150mg/dL
should be followed up according to the Neonate Blood Glucose
Testing procedure located in the Nursing unit procedure manual.
Test cycle not completed due to problem with the sample, calibrant
solution, sensors, mechanical or electrical functions of the analyzer:
take the action displayed with the message that identifies the problem.
Refer the problem to the Laboratory Point of Care Coordinator if
Display Stored Results:
To recall a stored test record to the display screen, press the MENU soft key
and select STORED RESULTS by pressing the "2" key, from the STORED
RESULTS menu, select DISPLAY A RESULT by pressing the "1" key.
Select the record to be displayed by pressing the key (1 to 5) on the pages (1
to 10) corresponding to the test record. The list of stored results can be listed
with Cartridge Type or Date/Time. Use the DIS key to toggle between these
display modes.
Printing Results:
Place the analyzer in the printer cradle. Turn the printer on (printer light
green) or press the paper advance key to reactivate.
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To print the displayed test record, press the PRT key on the analyzer. The
most recent test record can be printed only if a patient identification number
has been entered or actively bypassed.
Do not move the analyzer while "Printing" is displayed. Note: Results
printed on thermal paper will fade with time and, therefore, not acceptable as
permanent chartable record.
Write the patient's name on the Pt name line, the physician's name on the
Physician line, and the Sample type on the Sample type line.
A stored test record can be printed without recalling the results to the screen.
Press the MENU soft key, select STORED RESULTS by pressing the "2"
key. From the STORED RESULTS Menu select PRINT RESULTS by
pressing the "2" key. Use the soft keys to page up or down through the 10
pages of stored test records, press the 1 to 5 keys to select the desired records
on each page. When a key is pressed, the number selected will reserve video
(dark background, light lettering). To deselect a record, re-press the key, the
number will return to light background, dark lettering.
The list of stored results can be listed with Cartridge Type or Date/Time.
Use the DIS key to toggle between these display modes. When all the test
records desired are selected, press the PRT key. The message
"PRINTING..." will be displayed while the records are transmitted to the
printer. Each record will take about 45 seconds to print.
To stop printing before all test records are printed, press the * key.
A test record cannot be printed from a position displaying INVALID or NO
DATA, an Electronic Simulator test or an error code.
Transmitting Results to the Central Data Station
i-STAT operators will transmit Arterial Blood Gas (ABG) results
immediately after completion of each ABG test.
Respiratory Therapy will transmit all results from each analyzer that ABGs
are performed on at the beginning of each shift.
Radiology will transmit all results at the end of first shift, Monday through
The Cardiac Cath Lab will transmit all results at the end of each case.
Place the analyzer in the IR Interface cradle. The IR Interface light must be
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To transmit all stored test records, press the * key or access STORED
RESULTS from the menu. Press the "3" key on the analyzer to transmit all
test records.
Do not move the analyzer while "Transmitting" is displayed.
During transmission the IR Interface light will blink alternately red and green.
If transmission is successful, the interface will emit a single high pitched
beep, and the light will return to green. An unsuccessful transmission is
indicated by three low tone beeps. In this case repeat the transmission
process. If unsuccessful the second time, notify the Laboratory Point of Care
Transmitting Results from the Central Data Station to the Lab Computer.
Test records will be routinely transmitted to LIS automatically via an AME interface.
The Laboratory Point of Care Office will transmit results manually from the Central
Data Station to the Laboratory Information System when AutoSend is off:
Use the up and down arrow keys on the Central Data Station to highlight the
patient test record to be transmitted.
Press the F9 key.
"_ _ _" indicates that the record is in queue.
". . ." indicates the record is being transmitted.
A check mark in the Central Data Station SENT column indicates that the
results have been transmitted.
Activate the Auto Send "on" to resume automatic transmission.
Reference Range
The i-STAT Reference Ranges have been derived from the literature and are
programmed into the i-STAT Analyzer. The reference ranges are as follows:
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The reference ranges listed below are those used by Durham Regional Hospital Laboratory
(serum/plasma samples for chemistries). Sodium, Potassium, Chloride, BUN, Glucose, Hematocrit,
Hemoglobin, and Creatinine values have been established by in-house normal range studies and
available literature. Arterial Blood Gases and ionized Calcium have been derived from the literature.
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Clinical Significance
Test for sodium in the blood are important in the diagnosis and treatment of patients suffering from
hypertension, renal failure or impairment, cardiac distress, disorientation, dehydration, nausea and
diarrhea. Some causes of increased values for sodium include dehydration, diabetes insipidus, salt
poisoning, skin losses, hyperaldosteronism and CNS disorders. Some causes for decreased values for
sodium include delusional hyponatremia (cirrhosis), depletional hyponatremia and syndrome of
inappropriate ADH.
Tests for potassium in the blood are important in the diagnosis and treatment of patients suffering
from hypertension, renal failure or impairment, cardiac distress, disorientation,
nausea and diarrhea. Some causes of increased values for potassium include renal glomerular disease,
adrenocortical insufficiency, diabetic ketoacidosis (DKA), sepsis and in vitro hemolysis. Some causes
of decreased values for potassium include renal tubular disease, hyperaldosteronism, treatment of
DKA, hyperinsulinism, metabolic alkalosis and diuretic therapy.
Tests for chloride in the blood are important in the diagnosis and treatment of patients suffering from
hypertension, renal failure of impairment, cardiac distress, disorientation, dehydration, nausea and
diarrhea. Some causes of increased values for chloride include prolonged diarrhea, renal tubular
disease, hyperparathyroidism and dehydration. Some causes for decreased values for chloride include
prolonged vomiting, burns, salt-losing renal disease, overhydration and thiazide therapy.
Urea Nitrogen/BUN
An abnormally high level of urea nitrogen in the blood is an indication of kidney function impairment
or failure. Some other causes of increased values for urea nitrogen include
prerenal azotemia
(e.g. shock), postrenal azotemia, GI bleeding and high protein diet. Some causes of decreased values
of urea nitrogen include pregnancy, severe liver insufficiency,
overhydration and malnutrition.
Glucose is a primary energy source for the body and the only source of nutrients for the brain issue.
Measurements for determination of blood glucose levels are important in the diagnosis and treatment
of patients suffering from diabetes and hypoglycemia. Some causes for increased values of glucose
include diabetes mellitus, pancreatitis, endocrine disorders (e.g. Cushings syndrome), drugs (e.g.
steroids, thyrotoxicosis), chronic renal failure, stress, or I.V. glucose infusion. Some causes of
decreased values of glucose include insulinoma, adrenocortical insufficiency, hypopituitarism,
massive liver disease, ethanol ingestion, reactive hypoglycemia, and glycogen storage disease.
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Hematocrit is a measurement of the volume of red blood cells. This is a key indicator of the body's
state of hydration, anemia or severe blood loss, as well as the blood's ability to
transport oxygen.
Some causes of increased values of hematocrit include dehydration,burns, impaired ventilation and
renal disorders. Some causes for decreased values of hematocrit include hemolytic anemias, iron
deficiency, marrow depression or blood loss.
Elevated levels of creatinine are mainly associated with abnormal renal function and occur whenever
there is a significant reduction in glomerular filtration rate or when urine elimination is obstructed.
The concentration of creatinine is a better indicator of renal function than urea or uric acid because it
is not affected by diet, exercise or hormones.
Ionized Calcium
Although most of the calcium in blood is bound to protein or complexed to smaller anionic species,
the biologically active fraction of calcium is free ionized calcium. Through its role in a number of
enzymatic reactions and in membrane transport mechanisms, ionized calcium is vitally important in
blood coagulation, nerve conduction, neuromuscular transmission and in muscle contraction.
Increased ionized calcium (hypercalcemia) may result in coma.Other symptoms reflect neuromuscular
disturbances, such as hyperreflexia and/or neurologic abnormalities such as neurasthenia, depression
or psychosis. Decreased ionized calcium often results in cramps (tetany), reduced cardiac stroke work
and depressed left ventricular function. Prolonged hypocalcemia may result in bone demineralization
(osteoporosis) which can lead to spontaneous fractures. Measurments of ionized calcium have proven
of value under the following clinical conditions: transfusion of citrated blood, liver transplantation,
open heart surgery, neonatal hypercalcemia, renal disease, hyperparathyroidism, malignancy,
hypertension, and pancreatitis.
pH is an index of the acidity or alkalinity of the blood with an arterial pH of <7.35 indicating an
acidemia and >7.45 alkalemia.
PO2 (partial pressure of oxygen) is a measurement of the tension or pressure of oxygen dissolved in
blood. Some causes for decreased values of PO2 include decreased pulmonary ventilation, impaired
gas exchange between alveolar air and pulmonary capillary blood, and alteration in the flow of blood
within the heart or lungs.
PCO2 along with pH is used to assess acid-base balance. PCO2 (partial pressure of carbon dioxide),
the respiratory component of acid-base balance, is a measure of the tension or pressure of carbon
dioxide dissolved in the blood. Causes of primary respiratory acidosis (increase in PCO2 ) are airway
obstruction, sedatives and anesthetics, respiratory distress syndrome, and chronic obstructive
pulmonary disease. Causes of primary respiratory alkalosis (decreased PCO2) are hypoxia due to
chronic heart failure, edema and neurologic disorders, and mechanical hyperventilation.
HCO3 (bicarbonate)
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HCO3 (bicarbonate) is an indicator of the buffering capacity of blood. Regulated primarily by the
kidneys, HCO3 is the metabolic component of acid-base balance. Causes of primary metabolic
acidosis are ketoacidosis , lactate acidosis, and diarrhea. Causes of primary metabolic alkalosis are
vomiting and antacid treatment.
TCO2 (total carbon dioxide)
TCO2 (total carbon dioxide) is a measure of carbon dioxide which exists in several states: CO2 in
physical solution or loosely bound to proteins. Bicarbonate ions make up all but approximately
2mmol/L of the total carbon dioxide of plasma. Measurement of TCO2 as part of an electrolyte
profile is useful chiefly to evaluate HCO3 concentration. TCO2 and HCO3 are useful in the
assessment of acid-base imbalance (along with pH and PCO2) and electrolyte imbalance.
Base Excess/BE
Base excess remains virtually constant during acute changes in the PCO2 and reflects only
nonrespiratory component of pH disturbances.
Limitations of Procedure
Proper venipuncture technique must be followed to avoid hemolysis of the sample or tissue fluid
(Droxia, Hydrea)
Hydroxyurea can cause significant errors in the measurement of Glucose, and Creatinine with the
i-STAT system. An alternate method must be used to measure Glucose and Creatinine when
patient’s have been administered hydroxyurea..
Hemodilution of the plasma by more than 20% associated with priming cardiopulmonary bypass
pumps, plasma volume expansion or other fluid administration therapies using certain solutions may
cause clinically significant error on Sodium, Chloride, Ionized Calcium, and pH
results. These errors are associated with solutions that do not match the ionic characteristics of
plasma. These errors can be avoided if when hemodiluting by more than 20%, physiologically
balanced multi-electrolyte solutions containing low-mobility anions (e.g. gluconate) such as
Normosol-R (Abbott Laboratories). Plasma-Lyte-A (Baxter Healthcare Corporation), and
Isolyte-S (B Braun Medical) are used.
Thiocyanate is a degradation product product of nitroprusside treatment and also a product of
thiosulphate treatment of cyanide poisoning.
It may cause falsely elevated Chloride results, or may cause chloride results to be suppressed (“star
Page 29 of 29
It can cause falsely decreased BUN/urea, and Glucose results. Preliminary studies indicated that
140mg/dL (24mmol/L) thiocyanate decreased BUN/urea results approximately 21%, and decreased
Glucose results approximately 23%.
37.5 mmol/L bromide will increase Sodium results by 5 mmol/L, and decrease Glucose by 30mg/L..
12.5mmol/L (100mg/dL) bromide will increase Chloride results by 30 mmol/L, and will increase
Creatinine by 0.8mg/dL (71 umol/L) from an initial creatinine concentration of 1.0 mg/dL (88
20 mmol/L lactate will decrease Sodium results by 5 mmol/L, and decrease Ionized Calcium results
by 0.05 mmol/L..
11 mmol/L (100 mg/dL) lactate will increase Chloride results by 3.5 mmol/L.
16 mmol/L (166 mg/dL) B-hydroxybutyrate will decrease Sodium results by 5 mmol/L, and will
increase Chloride results by 3 mmol/L..
20 mmol/L B-hydroxybutyrate will decrease Ionized Calcium results by 0.1 mmol/L.
4 mmol/L salicylate will increase Chloride results by 5 mmol/L.
4.34 mmol/L salicylate will decrease Ionized Calcium results by 0.1 mmol/L.
1.0 mmol/L magnesium above normal will increase Ionized Calcium results by 0.04 mmol/L.
11 mmol/L ascorbate will cause a 0.7 mg/dL increase in Creatinine.
The use of blood collection tubes containing sodium heparin as an anticoagulant may
increase sodium results up to 1 mmol/L.
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If heparanized whole blood is allowed to stand before testing, potassium values will first
decrease slightly, then increase over time. Potassium will increase in iced specimens.
Potassium values from anticoagulated samples are preferred to serum values because 0.1 to
0.7 mmol/L potassium can be released from platelets and red blood cells during the clotting
process. Potassium values obtained from skin puncture samples may vary due to hemolysis
or an increase in tissue fluid from improper technique during the collection procedure.
Glucose values will decrease in whole blood samples over time. Venous blood glucose is as
much as 7 mg/dL less in capillary blood glucose as a result of tissue utilization.
Values below 7.4 at 37 Cdecrease results by approximately
0.9 mg/dL (0.05 mmol/L) per 0.1 pH units. Values above
7.4 at 37 C
increase results by approximately 0.8 mg/dL (0.04 mmol/L) per
0.1 pH units.
Oxygen levels of less than 20mmHg (2.66 kPa) at 37 C may
decrease results.
Grossly elevated WBC counts may increase results.
High Hematocrit results can be caused by settling of red blood cells in the sample.
Low hematocrit results can be caused by contamination from flush solutions in an arterial or
venous line.
Hematocrit results are affected by the level of total protein as follows:
For HCT values below 40%PCV:
For Total Protein values below 6.5g/dL, HCT decreased by 1% PCV for each
decrease of 1g/dL TP.
For Total Protein values above 8.0g/dL, HCT increased by 1% PCV for each
increase of 1g/dL TP.
For HCT values above 40%PCV:
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For Total Protein values below 6.5g/dL, HCT decreased by 0.75% PCV for each
decrease of 1g/dL TP.
For Total Protein values above 8.0g/dl, HCT increased by 0.75%PCV for each
increase of 1g/dL TP.
Abnormally high lipids may increase results. Interference from lipids will be about
two thirds the size of the interference from protein.
The sample electrolyte concentration is used to correct the measured conductivity
prior to reporting hematocrit results. Factors that affect sodium will therefore also
affect hematocrit.
Ionized calcium
Venous stasis (prolonged tourniquet application) and forearm exercise may
increase ionized calcium due to a decrease in pH caused by localized
production of lactic acid. Exposing the sample to air will cause an increase
in pH due to the loss of CO2 which will decrease ionized calcium.
Heparin binds calcium. Each unit of heparin added per mL of blood will
decrease ionized calcium by 0.01mmol/L. The correct ratio of heparin
anticoagulant to blood must be achieved during sample collection.
Intravenous injection of 10,000 units of heparin has been shown in
adults to cause a significant decrease of ionized calcium of about
Affect of Freezing: Cartridges should be stored between 2 and 8 C. Freezing should be
avoided. Freezing will cause the ionized calcium in the calibrant fluid to precipate, which
will cause sample results to be falsely elevated. To help avoid freezing, do not store
cartridges against the walls of the refrigerator. If freezing is suspected, test a sample of the
cartridges using i-STAT controls.
Venous stasis and forearm exercise may decrease pH due to localized production
of lactic acid. Exposing the sample to air will cause an increase in pH due to the
loss of CO2. pH decreases on standing anaerobically at room temperature at a
rate of 0.03 pH units per hour.
Exposure of the sample to air will cause an increase in PO2 when values are below
150 mmHg and a decrease in PO2 when values are above 150 mmHg (approximate PO2
of room air).
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Standing anaerobically at room temperature will decrease pH at a rate of 0.03 per
hour, will increase PO2 by approximately 4mmHg per hour and will decrease PO2
at a rate of 2-6 mmHg per hour.
Do not ice samples before testing-PO2 results may be falsely elevated in cold samples. Do
not use a cold cartridge.-PO2 results may be falsely decreased if the cartridge is cold.
sO2 values calculated from a measured PO2 and an assumed oxyhemoglobin
dissociation curve may differ significantly from the direct measurement.
Exposing the sample to air allows CO2 to escape which causes PCO2 to decrease
and pH to increase and HCO3 and TCO2 to be under-estimated.
Allowing blood to stand (without exposure to air) before testing allows PCO2 to
increase and pH to decrease which will cause HCO3 and TCO2 to be overestimated due to metabolic processes.
For Creatinine values below 2 mg/dL:
For PCO2 values above 40, creatinine values are increased by 6.9% for every 10
For PCO2 values below 40, creatinine values are decreased by 6.9% for every 10
For Creatinine values above 2 mg/dL:
For PCO2 values above 40, creatinine values are decreased by 3.7% for every 10
For PCO2 values below 40, creatinine values are increased by 3.7% for every 10
A creatine level of 5 mg/dL will cause a 0.20 mg/dL increase in Creatinine. Creatine
may be elevated in patients using creatine supplements, experiencing muscle trauma
or other primary or secondary myopathies, taking statins for hyperlipidemia control, or
in patients with hypothyroidism or a rare genetic defect of the creatine transporter
i-STAT Cartridge and Test Information Sheets for Sodium, Potassium,
Chloride, Glucose, BUN, Hematocrit, revised November 1996. The i-STAT
Corporation, Princeton, New Jersey.
i-STAT System Manual, revised October 2003. The i-STAT Corporation,
Princeton, New Jersey
Page 33 of 33
Tietz, Norbert W., Clinical Guide to Laboratory Tests, pp. 446-447, pp 398399, pp. 110-111, pp. 230-231, pp. 492-493, pp. 258-259, W. B Saunders
company, Philadelphia, PA., 1983.
Procedure Written By: Kathryn Winston, 10/04
Procedure Revised By: Kathryn Winston, 10/94, 11/95, 8/96, 6/97, 10/97,5/98,7/98,11/98,11/99,
2/00,3/00,10/00,1/01,6/01,11/01, Susan Montsinger 4/04, 5/05
Procedure Reviewed By:
John T. Daly, M.D.
DRH Laboratory Director
Mark Powers, M.D.
Director of Arterial Blood Gas Laboratory
Susan Montsinger BS,MT(ASCP) Date
Point of Care Coordinator
Charles Alford, RRT
Director of Cardiopulmonary Services