Pathology/Lab Coding Alert

Question: An insurance company recommended  we code influenza test A+B as CPT 87804 and 87804-91. Is this correct?


Ohio Subscriber


Answer: You should code an influenza test based on the lab method. Use 87804 (Infectious agent antigen detection by immunoassay with direct optical observation; influenza) for a direct-observation test. But if you use a detection method such as enzyme immunoassay (EIA), you should report 87400 (Infectious agent antigen detection by enzyme immunoassay technique, qualitative or semiquantitative, multiple step method; Influenza, A or B, each).

The most straightforward use of modifier 91 (Repeat clinical diagnostic laboratory test) is when a physician orders the same test--such as blood glucose (82947, Glucose; quantitative, blood)--more than once for the same patient on the same day to obtain multiple results in the course of patient treatment. But you might also use modifier 91 when a single code describes the same test for different analytes or organisms. In this case, codes 87804 and 87400 can describe an influenza A or influenza B test.

If your payer recommends using modifier 91 to indicate that you performed the test twice, once for type A and once for type B, you may do so. If your payer requests that you use units (for instance, 87400 x 2), however, that is also acceptable. Code 87400 clarifies that you should report it once for each Influenza strain because the definition says, "Influenza, A or B, each."

Caution: Remember that you should use modifier 91 only when repeating a laboratory test is medically necessary in the course of patient treatment. Do not use 91 if the lab runs the test again for the following reasons:

• To confirm initial results
• Because of testing problems related to specimens or equipment
• For any other reason when a normal, one-time reportable result is all that the physician needs for appropriate patient treatment.