Pathology/Lab Coding Alert

Don't miss specific virus type or Ig class

If you don't report a separate code for each virus antibody, your lab could stand to lose about $12 to $25 per test for codes 86602-86804. You-ll need to understand the basics of virus classification and immunoglobulin class to avoid this costly mistake.

Learn the following virus-identification basics and new CPT coding rules to make the most of your lab's infectious agent antibody immunoassays.

Distinguish Genus, Species or Type

Identifying a virus could mean knowing only the genus -- sort of like knowing a person's last name. But if the physician wants to know more specifically what the virus is, the lab might have to further identify the virus by species or even type -- similar to knowing a person's first and middle names as well as the last name.

If the lab performs multiple specific classes or types of antibody tests to arrive at this level of identification, you should separately report each test, says William Dettwyler, MT-AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore. Sometimes you-ll find different CPT codes for each specific test, making code selection easy. 

For instance: The physician requests antibody immunoassays for herpes simplex 1 and herpes simplex 2. The lab performs one assay for each viral type, and you should report 86695 (Antibody; herpes simplex, type 1) and 86696 (Antibody; herpes simplex, type 2), respectively, for the tests.

But sometimes your lab might perform separate tests for different viral species or types for which CPT doesn't provide individual codes. That's when you-ll need to report multiple units of the more general code -- or risk losing payment for your lab's work.

For example: The physician wants the lab to perform separate immunoassays for antibodies to coxsackie A and B species. CPT provides only one code for enterovirus antibodies (coxsackie is a type of enterovirus). Because the lab performs two separate tests, you should code 86658 (Antibody; enterovirus [e.g., coxsackie, echo, polio) x 2 units.

Exception: Be aware that many payers require you to bill this as 86658 and 86658-59 (Distinct procedural service) instead of listing 86658 x 2, according to Dettwyler. Or you might find payers that expect modifier 91 (Repeat clinical diagnostic laboratory test) when you report multiple immunoglobulin classes with the same CPT code, says Kenneth Wolfgang, MT (ASCP), CPC, CPC-H, CEO of Chargemaster Maintenance Services, a laboratory consultation company in Portland, Ore.

Report Each Immunoglobulin Class, Too

Because the immunoglobulin (Ig) class can be the key to understanding viral infection and immunity, physicians often order tests for more than one Ig class for a specific virus. See -Don't Let Immunoglobulin Class Confuse You -- Here's What You Need to Know- in this issue to learn more about what these tests mean.

One test = one code: Just as you should report one code for each test for a viral species or type, so you should report one code for each separate test for a viral Ig class.

For instance: If the lab tests for total immunoglobulins for Hepatitis B core antibody, you should report 86704 (Hepatitis B core antibody [HBcAb]; total). If the physician also orders IgM class for HBcAb, you should also report 86705 (Hepatitis B core antibody [HBcAb]; IgM antibody).

CPT 2007 Clarifies Coding

Physicians commonly order tests for IgM and IgG antibodies for a single infectious agent. 

Quandary: Although you-ll see a few specific IgM codes, CPT doesn't provide different codes for IgG class for any virus type. CPT also didn't provide any direction about how to report IgG -- until now.

Solution: CPT 2007 adds IgG reporting directions in the instructional note for codes 86602-86804. The new directions state, -When a coding option exists for reporting IgM specific antibodies, the corresponding nonspecific code may be reported for performance of - an IgG analysis.- This instruction applies to the following codes:

- 86631 -- Antibody; Chlamydia

- 86632 -- Antibody; Chlamydia, IgM

- 86644 -- Antibody; cytomegalovirus (CMV)

- 86645 -- Antibody; cytomegalovirus (CMV), IgM

- 86777 -- Antibody; Toxoplasma

- 86778 -- Antibody; Toxoplasma, IgM

- 86788 -- Antibody; West Nile virus, IgM

- 86789 -- Antibody; West Nile virus.

For example: The physician orders Chlamydia IgG and IgM antibody tests to determine the status of current infection with the organism. The lab performs two separate assays and reports IgG and IgM levels to the physician. For the IgG test, you should report 86631 (Antibody; Chlamydia), and for the IgM test, you should report 86632 (Antibody; Chlamydia, IgM), according to Dettwyler. -Although labs may have been using this coding combination in the past, CPT 2007 clarifies that these are indeed the proper codes for these tests,- Dettwyler says.