Pathology/Lab Coding Alert

Question: Our lab performs an immunoassay drug screen for six drug classes for a Medicare beneficiary, and we have CLIA certification for high-complexity tests. Should we bill G0431?

Louisiana Subscriber

Answer: The correct code depends on the complexity of the test you perform, not on your CLIA certification level (assuming you're approved for the level and type of test you perform).

Immunoassay drug screens can be moderate or high complexity, depending on the manufacturer and/or instrumentation. For the work you describe for Medicare coverage, you should report one of the following codes depending on the complexity of the test:

• G0431 -- Drug screen, qualitative; multiple drug classes by high complexity test method (e.g., immunoassay, enzyme assay), per patient encounter
• G0434 -- Drug screen, other than chromatographic; any number of drug classes, by CLIA waived test or moderate complexity test, per patient encounter

Watch reimbursement: You don't want to make n $82 mistake by billing a high-complexity test as a moderate complexity test. Medicare pays $102.99 for G0431, but only $20.60 for G0434 (2012 Clinical Laboratory Fee Schedule national limit amount).