What is the Common Working File (CWF)?

What is the Common Working File (CWF)?
It is very important to pay careful attention to the number of sessions your cardiac rehabilitation (CR) and pulmonary
rehabilitation (PR) patients have attended. Remember that “pulmonary rehabilitation” refers to the service provided to
a patient with COPD only. CMS does not, at this time, track the number of sessions of Respiratory Therapeutic Services
(G0237, G0238, G0239) for patients with a diagnosis other than COPD.
The Centers for Medicare and Medicaid (CMS) allows 36 sessions of CR and PR. If the patient exceeds 36 sessions since
the rule was implemented on 1/1/10, the KX Modifier must be added to the claim, and medical necessity for continuing
beyond 36 sessions must be documented. All claims for session 37 and beyond without the KX modifier will be denied
by Medicare.
Per Change Request 6850, Transmittal 129 (5-21-2010), a new qualifying diagnosis makes a patient eligible for a new
course of CR. An example of this would be a Medicare patient who is eligible for CR after an AMI in 2010, after CABG in
2011, and after another CABG in 2013. The KX modifier must be used for all CR sessions beyond the initial 36 received as
a Medicare beneficiary, whether used in the same calendar year or future years. The CMS tracking for CR sessions began
01/01/10. Use of the KX modifier is attestation that there is medical necessity. This replaces the need for pre-approval
for a new course by the Medicare contractor.
If the MAC does not agree that the sessions are medically necessary, they may still deny payment. You cannot obtain
preauthorization for sessions beyond 36.
The CWF is a Medicare file that indicates how many Cardiac Rehab (CR) sessions are used for a patient or how many
Pulmonary Rehab (PR) are remaining for a patient. The file looks like this:
(HCPC: G0424)
(HCPCS: 93797, 93798)
(HCPCS: G0422, G0423)
Patient Name
The technical column (TECH) indicates how many sessions are remaining for the patient. So in the example above, the
patient has used 10 sessions of PR, with 62 remaining. The patient has not used any CR sessions. You should be
checking the CWF for all CR and PR patients referred to your programs. This can be done through your billing office or
through applications such as MedeAnalytics. Your hospital may subscribe to a different product, but would have access
to the same information. Please make sure you have a source of obtaining the information from the CWF. If you have
questions, don’t hesitate to contact your IACPR Reimbursement Contact People:
Cardiac Rehab: Candy Steele, [email protected]
Pulmonary Rehab: Janie Knipper, [email protected]