Providers are reminded that effective retroactively for dates of service on or after October 1, 2005, the following CPT-4 codes may be billed with modifier QW (CLIA-waived tests):
||Thyroid stimulating hormone (TSH)
||Transferase; aspartate amino (AST) (SGOT)
||Platelet, aggregation (in vitro), each agent
||HIV-1 and HIV-2, single assay
Modifier QW indicates that the provider certifies that a specific test kit from manufacturers identified by the Centers for Medicare & Medicaid Services (CMS) was used when performing the test. All claims billed with modifier QW that were denied due to the provider not being certified for the laboratory procedure billed will be automatically reprocessed.