CLIA: Laboratory Tests

Denial Reason, Reason/Remark Code(s):

  • CO-B7: This provider was not certified/eligible to be paid for this procedure/service on this date of service


  • HCPCS modifier QW must be submitted with certain clinical laboratory tests that are waived from the Clinical Laboratory Improvement Amendments of 1988 (CLIA) list. The Food and Drug Administration (FDA) determines which laboratory tests are waived.
  • Note: Not all CLIA-waived tests require HCPCS modifier QW
  • Determine if the CPT code is a waived test by accessing the CMS CLIA web page
  • Palmetto GBA will publish information on tests newly classified as 'waived' on our website. Please note, the list of CLIA-waived procedures is updated as often as quarterly.
  • The CLIA certificate number is also required on claims for CLIA waived tests. Submit this information in Loop 2300 or 2400, REF/X4, 02 for electronic claims. For paper claims, submit the CLIA certification number in Item 23 of the CMS-1500 claim form.
  • Access complete instructions for correctly submitting HCPCS modifier QW in the Palmetto GBA Modifier Lookup tool.



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