Beginning Nov. 25, don't be surprised when your PSA claims for Medicare patients get denied when you report any of the following ICD-9 codes with CPT 84153 (Prostate specific antigen [PSA]; total). They are not covered, according to CMS's latest national coverage determination for diagnostic laboratory services. If one of the above diagnosis codes is the reported reason for the PSA test, CMS recommends you remind laboratories to use modifier -GZ when submitting the claim to indicate they are billing a noncovered service fully expecting a formal denial. Modifier -GA should be used if the patient signed an advance beneficiary notice (ABN) and not -GZ. For Medicare purposes, modifiers -GZ and -GA indicate that the test was used for screening and that consideration should be given to G0103 (Prostate cancer screening; PSA, total).