Pathology/Lab Coding Alert

Question: When our lab performs rapid testing for influenza A and B, should we use modifier 91 to distinguish the second unit of the lab test code?

Georgia Subscriber

Answer: According to the AMA, the correct modifier choice for reporting two rapid influenza test results (87804, Infectious agent antigen detection by immunoassay with direct optical observation; influenza) is modifier 59 (Distinct procedural service).

“When two units of code 87804 are submitted, modifier 59 may be used to indicate that the two results represent separate services (codes 87804 and 87804-59),” according to CPT Assistant (May 2009). Because the same CPT code describes the rapid testing of both strains, you should use modifier 59 to indicate separate tests. Alternatively, the payer may prefer that you don’t use a modifier and list two units of 87804 (87804 x 2).

Alternative: If a payer instructs you to instead use modifier 91 (Repeat clinical diagnostic laboratory test) with two distinct influenza tests, keep a copy of the guideline in your compliance binder. Use modifier 91 when a patient’s treatment requires repeating the same lab test on the same day to obtain subsequent results. “An example is repeated blood testing for the same patient, using the same CPT code, performed at different intervals during the same day (e.g., initial and three subsequent potassium levels),” states the AMA in “Coding Brief: Rapid Influenza Virus A and B Testing (Code 87804).”