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gation; (b) by using Sure-Sep and single
centrifugation;
and (c) by using SST and
mannitol, excessive mannitol infusion to
patients will result in falsely increased
“triglyceride”
results that will not be
compatible with the lipoprotein profile.
Under such conditions, true tniglycer-
and Lederer (3), there was a slight effect
of “Serum Disc” (Whale Scientific,
Denver, Cob.) on serum total cholesterol and triglyceride.
They indicated a
ides can be estimated
difference in cholesterol when compared
in Table
to the control sera. It was not stated
whether the changes were increases or
By Students’ t-test, the samples prepared with the SST showed no significant difference in concentration
when
compared to the conventional method,
but showed a significant (P < 0.001)
lowering when Sure-Sep
was used.
Values for triglycerides were 4.3% lower
and for total cholesterol 4.2% lower than
by running an
unsaponified blank sample that will
eliminate
the free glycerol and mannitol
interference
of the test.
2% difference
I. Young, D. S., Pestaner, L. C., and Gibberman, V., Effects of drugs on clinical laboratory
tests. Clin. Chem.
21, 1D (1975).
Special issue.
and
1.5%
decreasesin the samples prepared with
“Serum
References
in triglycerides
Disc.”
Mathies (4) evaluated
the suitability
of a new separatory
device, “Sure-Sep”
(General Diagnostics, Morris Plains,
N.J.), and found that there was no effect
of this
silicone-polymer-silica
barrier
2. Witter, R. F., and Whitner, V. S.,
complex on serum lipids. This method
mination of serum triglycerides.
Lipids and Lipoproteins:
Quantitation,
Composition, and Metabolism, G. J. Nelson,
Ed., Wiley-Interscience,
New York, N.Y.,
is based on a container
(filled with a
semi-solid polymer) that is placed in the
top of the blood-drawing
tube before
centrifugation.
1972, pp 75-111.
Technicon Autoanalyzer
Clinical Method
No. 24, Simultaneous
Cholesterol
and Tnglyceride Analyses, Technicon
Instruments
Corp., Tarrytown, N.Y., 1972.
through
DeterIn Blood
3.
Herbert
K. Naito
Vytenis
J. Gatautis
Department
of Atherosclerosis
and Thrombosis
Research,
Division
of Research;
Department
Division
and
of Biochemistry
ofLaboratory
Medicine
Kathryn
L. Popowniak
Department
of Nephrology
and
Hypertension
The Cleveland
Clinic Foundation
Cleveland,
Ohio 44106
The polymer descends
the serum
(6) were not significantly
affected
as
compared to the conventional
method
of double centrifugation of the serum
samples.
Bernstein
reported
that using his
enzymic assay for serum total cholesterol (8) the Sure-Sep technique for
separation of serum caused no statistical
differences when compared
to the conventional
method of serum
significant
separation.
Recently a new serum separation device has been introduced. It is a serum
Vacutainer tube, “SST” (Becton-Dickinson, Rutherford,
a
silicon
Separating Devices on Results
for Cholesterol and Triglyceride
centrifugation,
(relative
the
density,
1.045)
Furthermore,
the silicon
complex floats along the side of the walls
collection.
It is essential that when using such
separator aids, there are no interferences
with the analytes that are to be measured in the serum. Essentially,
this
means that the separatory
material
should be inert, have no effect on the
concentration
of the serum of plasma
constituents,
and
not
high-molecular-weight
plexes seen in some
cryoglobulins,
“trap”
certain
protein
disease
states
com(i.e.,
lipoprotein-immune
complexes
and certain
and Williamson
using
of the tube, following a course of least
resistance to the blood cells, and layers
itself at an angle, minimizing
the trauma
of the centrifugal
force on the packed
(1 ) showed
the semi-automated
cholesterol method of Block et al. (2)
and the triglyceride method of Kessler
1.
the values obtained from the serum obtamed by the conventional method. The
serum samples that were selected coyered a triglyceride concentration range
of 0.91 to 22.7 g/liter
and cholesterol
concentration
range of 1.56 to 4.40 g/
liter. When the difference in values be-
tween the
Sure-Sep
technique
and
conventional technique was plotted vs.
concentration,
the correlation
coeffi-
cients
for triglycerides
and total cholesterol were 0.19 and 0.33, respectively.
This indicates that the degree of decrease in lipid values caused by SureSep was not related to the concentration
of the serum lipids. The observed decrease in serum lipid values seen in our
study
with Sure-Sep is in contrast to the
report of Bernstein (8) and Mathies (4),
while our data indicating that the SST
method does not interfere with triglyc-
eride and cholesterol
determinations
agrees with the recent article of Laessig
et al. (10). Further studies are necessary
to fully assess the usefulness of any
separator
devices
including
the
SST-i.e.,
the influence of such syn-
barrier
complexes
on cryoglobu-
lins, macroglobulins,
globulin
complexes,
lipid-immunoand
other
high-
molecular-weight
protein or carbohydrate complexes. It has been our experience that when using Sure-Sep, the
silicon-polymer
complex will layer itself
on the cryoglobulins, thereby “trapping”
the cryoglobulins
with the clot when the
serum is decanted
into another
tube.
cells.
We compared the effects
of these
de-
vices, Sure-Sep and SST, on serum total
cholesterol
and triglyceride
determinations. The AutoAnalyzer
II procedure
for simultaneous
determination
of cho-
lesterol and triglycerides
the
study.
toAnalyzer
A modification
II method
was used for
of the
Au-
(9) was run ac-
to the procedure outlined by the
Lipid Standardization Laboratory at the
cording
Center for Disease Control, Atlanta,
for standardization
and certification
total cholesterol and triglyceride
termination.
245
proteins).
936
complex
termediate.
materials has been introduced
to facilitate the separation of serum from the
blood clot by (a ) improving the yield of
serum, (b) obtaining better separation
of the serum from the blood cells, and
(c ) increasing the speed of the serum
when
During
The results of the
three methods of serum separation on
results for lipid concentration are shown
thetic
between the clot and the
serum because its relative density is in-
Since 1965, the use of many synthetic
Kaplan
N.J.) which contains
silicon-polymers-silica
takes a position
To the Editor:
that
semi-solid
complex.
Effect of Two New Serum-
globulin
during centrifugation
and becomes layered on the blood clot,
which then separates the cells from the
serum. Mathies reported that procedures for cholesterol
(2), triglycerides
(5), phospholipid (6, 7), and total lipid
single centrifugation.
Ninety-five
patients
were
Ga.,
for
de-
CLINICAL CHEMISTRY, Vol. 22, No. 6, 1976
Method of
Triglycerides
separation
way, by double centrifu-
Cholesterol
g/llter
Conven-
1.733 ±
2.456 ±
tional
SST
0.130
1.744±
0.052
2.486±
Sure-Sep
0.129k’
1.658 ±
0.053”
2.353 ±
0.125c
0.049c
selected
without
conscious bias for the study;
three tubes of blood were obtained from
each patient. Serum was obtained in the
following way in a random sequence: (a)
conventional
Table 1. Effect of Different CellSeparation Methods on Serum
Lipid
8
95 samples
a
4,
NonsIgnificant
cp<
0.001
Thus,
while
these
unusual
protein
complexes are rare, they may not be
detected when such serum-separator
devices are used.
GM OIIOMATOOW8I
____
References
1. Kaplan, A., and Williamson,
L., Effect on
chemical values of using polystyrene beads
for serum separation. Clin. Chem. 20, 403
fGOW
.
MAJ
Letter to the Editor.
2. Block, W. D., Jarrett, K. J., Jr., and Levme, j. B., An improved automated determi(1974).
nation
of serum total cholesterol
S
with single
color reagent. Clin. Chem. 12, 681 (1966).
3. Kessler, G., and Lederer, H., Fluorometric
measurement of triglycerides. In Automation
in Analytical
Chemistry,
Technicon
Symposia 1965, L. T. Skeggs et al., Eds. Mediad
Inc., New York, N. Y., 1966, p 341.
4. Mathies, J. C., Evaluation
of a new device
for rapidly separating serum or plasma from
blood. Clin. Chem. 20, 1573 (1974).
I
.x-
R. E., Further
Sep technique
for serum-plasma separation.
22, 120 (1976). Letter to the
Clin. Chem.
Editor.
9. Technicon
AutoAnalyzers
Method
No. 24, Simultaneous
750
II. Clinical
of a serum separator
(1976).
Herbert
K. Naito
Vytenis
J. Gatautis
Sst#{248}rr’
GC
the
Cholesterol!
Triglycerides. Technicon Instruments Corp.,
Tarrytown, N. Y., 1972.
10. Laessig, R H., Westgard, J. 0., Carey, R.
N., et al., Assessment
-
isPovd fo
Dt-ugDetectior ir’
CIiricd LthorotorU*
use of the Sure-
device for obtaining serum specimens suitable for clinical analyses. Clin. Chem. 22, 235
#{149}
GOW-mAC _________
(1932).
8. Bernstein,
_ _
TF-cz
5. Soloni, F. G., Simplified manual micromethod for determination of serum triglycerides. Clin. Chem. 17, 529 (1971).
6. Folch, J., Lees, M., and Sloane Stanley, G.
H., A simple method for the isolation and
purification
of total lipids from animal
tissues. J. Biol. Chem. 191, 833 (1957).
7. King, E. J., The colorimetric determination of phosphorus. Biochem. J. 26, 292
-
have found that the Model 750 FID gas
system is fast and reliable in stat drug analyses.
it’s a dedicated
GC, one which is easily used again and
Many clinical
laboratories
chromatograph
Because
again for similar tests, it’s easier to operate
and more expensive
analytical
tools.
complete
system
than the elaborate
- everything
you’ll need is under
the 69-750 standard
FID chromatograph,
glass column,
sampling
syringe
and an
kit.
Department
of Atherosclerosis
and Thrombosis Research
The
Division
of Research,
and
Department
of Biochemistry
Division of Laboratory
Medicine
rotameters,
easy-to-use
The Cleveland Clinic Foundation
Cleveland, Ohio 44106
GOW-MAC
has a packet of information
that will convince
install a 750 GC system in your laboratory.
$2500.00. It includes:
recorder,
installation
GOW-MAC,
a new name in the clinical laboratory
edged name in analytical
instrumentation.
0 Bibliography
Data Handling and Reporting
-
you to
an acknowl-
and reprints available.
To the Editor:
We read with
interest the paper by
et a!. (1 ). However, inspection
of the figures displaying the linearity
and the patient comparison data raises
Forrester
several questions relating to data collection and interpretation. The authors
are referred to Barnett and Youden (2)
for the mechanics of methods comparison and Westgard and Hunt (3) for the
use and interpretation
of statistical
(GOw
M A)
GOW-MAC
INSTRUMENT
CO.
Road, Madison,
N.J. 07940
100 Kings
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Shannon
201/377-3450
Free
Circle No. 361 on Readers
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Ireland
Service Card
27
tests
in methods comparison. Westgard and
CLINICAL CHEMISTRY, Vol. 22, No. 6. 1976
937