Primary Care Coding Alert

Question: When reporting 87804 to describe testing for rapid influenza virus A&B, should the second test have modifier 91?

Illinois Subscriber

Answer: Per the AMA, the correct choice for 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 results. Alternatively, the payer may prefer no modifier and two units of 87804 reported once (87804 x 2).

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)."

-- Information for and answers to You Be the Coder and Reader Questions reviewed by Kent Moore, manager of health care financing and delivery systems for the American Academy of Family Physicians in Leawood, Kan.