Pathology/Lab Coding Alert

Lab method directs code choice.

Influenza -- is that A or B? If your lab test helps you answer the A/B question, you might be able to report two units of the test code. Missing the second test could cost your lab up to $27 in lost revenue.

The following expert tips can help you get your flu coding on course to capture all the pay you deserve.

Report 87400 for 'Each'

If your lab performs a test that looks for influenza A or B antigens using enzyme immunoassay (EIA) technique, you should use 87400 (Infectious agent antigen detection by enzyme immunoassay technique, qualitative or semiquantitative, multiple-step method; influenza, A or B, each). The specimen source for this test may include blood, nasopharyngeal wash, throat swab, or sputum.

"Whether positive or negative, if the EIA antigen test involves results for A and for B, you should list 87400 x 2," says William Dettwyler, MT AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore.

Caution: If the EIA test provides a qualitative determination for influenza A and B but doesn't differentiate between the two strains, you shouldn't report 87400. For instance, ZymeTx Zstatflu gives a positive reading in the presence of A or B antigens, with no distinction.

Do this: Instead, you should report the test using unspecified code 87449 (Infectious agent antigen detection by enzyme immunoassay technique qualitative or semiquantitative; multiple-step method, not otherwise specified, each organism).

87804 Warrants 2

For an influenza test that uses an immunoassay leading to an observable result, such as a color change, you should report 87804 (Infectious agent antigen detection by immunoassay with direct optical observation; influenza).

For a test that does not identify the influenza strain -- one that involves a single positive or negative result for influenza -- report one unit of 87804.

Opportunity: The 87804 definition doesn't specify "each" for influenza A and B, but you may be able to bill for both.

If you use a test that differentiates between influenza A and B and you document both results, you should report 87804 twice, says Mary Noahr, office manager at a physician practice in Tulsa, Okla.

You may find differences in how payers want you to report multiple units of 87804. Here's how to decide which method to use:

Best practice: Report two units of 87804 if the payer allows it, Noahr says. Many Medicare Administrative Contractors (MACs) allow you to report 87804 x 2, because the medically unlikely edits (MUEs) limits you to two units of 87804.

For payers that deny the second 87804 charge as a duplicate, use modifier 59 (Distinct procedural service) on the second 87804 entry. The May 2009 CPT Assistant states, "Use modifier 59 when separate results are reported for different species or strains that are described by the same CPT code."

Fallback method: In some rare cases, such as certain state Medicaid providers, your payer may tell you to use modifier 91 (Repeat clinical diagnostic laboratory test) on the second listing of 87804.

Use 87254 Per Virus Strain

Labs may perform a rapid culture and direct antigen test to differentiate type A and B influenza. Physicians often order this test because it provides a quick response and high sensitivity.

The proper code for this test method is 87254 (Virus isolation; centrifuge enhanced [shell vial] technique, includes identification with immunofluorescence stain, each virus).

A negative test result indicates no influenza infection, while a positive result indicates the presence of influenza A or B, as specified.

Because the test is for influenza A and B, you should report two units of 87254 for the test.

86710 Depends on Antibody

Physicians may order influenza antibody test(s) on a blood sample to help identify influenza A or B infection. The presence of IgG antibody shows previous exposure to the virus, while IgM antibody presence shows current acute infection. The method may be enzyme-linked immunosorbent assay (ELISA) or other methods. The key is that this is an antibody test, not an antigen test.

You should code this service as 86710 (Antibody; influenza virus).

Capture 2 or 4: Like the other test codes, if the lab tests for influenza A and B, you can list the code twice (86710 x 2). But that's not all for the antibody test. Because the lab may test for IgG and IgM, you can report a separate code for each of those antibodies. If you test for each antibody for each influenza strain, you'll have four units of 86710.