G0431 – Drug screen, qualitative; single drug class method (e.g., immunoassay, enzyme assay), each drug class

This HCPCS code must be used when reporting any qualitative single drug or drug class assay. This includes individual drug or drug class assays performed using CLIA moderate or high complexity instruments as well as point of care devices which produce results for only one drug or class of drugs.

Medicare reimbursement for G0431 will continue to be $19.72.

G0431QW – Drug screen, qualitative; single drug class method (e.g., immunoassay,
enzyme assay), each drug class, CLIA waived test

This new HCPCS code will become effective April 1, 2010, and must be used when reporting qualitative, single drug class assays classified as “CLIA waived” by the
FDA.

Medicare reimbursement for G0431QW will be $19.72 after April 1, 2010. A key difference between codes G0430 and G0431 is that G0430 is reported per procedure, while G0431 is reported for each drug class. Also, G0430 applies only to non-chromatographic methods, while G0431 can be used for any method.

The definition of a procedure is typically a single device (such as a test cup, test strip or card) or a separate set of reagents used with an instrument to produce one or more test results. Thus, G0431 would be used to report individual drugs or drug classes determined using immunoassay instruments employing discrete reagent sets. The code would be reported once for each drug or drug class determined.

Likewise, if more than one point-of-care test device for a single drug or single drug class is employed, the test results from each device would be separately reported using G0431. At present CMS has assigned no frequency limits for G0430 and G0431. Since these are new codes, they have not yet been assigned Correct Coding Initiative frequency limits (MUEs). It is expected that, in the near future, G0430 will be assigned an MUE value of 1 since CMS would not expect the code to be reported more than one time for each date of service. G0431 will probably be assigned a higher, but unpublished, frequency limit. It is CMS policy to keep frequency limits they believe may be abused confidential. Medically necessary services that exceed MUE frequency limits may be reported as
separate line items using an appropriate modifier such as 59 (separate and distinct service) or 91 (repeat clinical test) to identify them as medically necessary. Since each line of a claim is individually adjudicated, this allows the MUE edit to be bypassed and all medically necessary codes to be paid. However, excessive use of the 59 modifier to bypass MUE edits has been targeted by the Office of Inspector General as a possibly abusive practice. Thus, care should be taken to document medical necessity of such tests in the patient record.

HCPCS codes G0430QW and G0431QW may be used to report any test cleared by the FDA as “waived”. Any correctly coded, medically necessary assay currently cleared by  the FDA should be reimbursed by Medicare/Medicaid contractors after April 1, 2010. The following table summarizes the use of qualitative drug testing codes for Medicare claims submitted after April 1, 2010.

CLIA Waived Modifier QW
CLIA Non-waived
Chromatography:
Multiple drug classes N/A* 80100
Single drug or drug class G0431QW G0431

Other methods:

Multiple drug classes G0430QW G0430
Single drug or drug class G0431QW G0431

*there are no CLIA waived, chromatographic, qualitative drug procedures, thus 80100QW is not included on the Medicare Laboratory Fee Schedule.