Pathology/Lab Coding Alert

Look for immunology, microbiology, chemistry, and more.

As clinicians test for myasthenia gravis, monkeypox, hepatitis D, and more next year, you’ll need to know how to code the tests they order.

That’s why we have this roundup of some new CPT^® 2024 codes that you might see in your lab.

Focus on Immunology

You’ll find four new codes in the immunology section for antibody tests that clinicians may order to help narrow down a diagnosis of myasthenia gravis (MG).

Glossary: MG is an autoimmune disorder that disrupts the interface of nerve and muscle, resulting in skeletal-muscle weakness. The condition often affects muscles that control the eyes, mouth, and limbs, but also may involve difficulty swallowing and breathing. The body may produce several auto-antibodies that attack some part of the system involved in transmitting nerve impulses to muscles.

Check out the relevant codes:

• 86041 (Acetylcholine receptor (AChR); binding antibody)
• 86042 (… blocking antibody)
• 86043 (… modulating antibody)
• 86366 (Muscle-specific kinase (MuSK) antibody)

AchR binding antibody is a common first-line test for the diagnosis of MG. Before the addition of this code, a CPT^® text note for AChR antibody directed coders to method-specific codes 83519 (Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; quantitative, by radioimmunoassay (eg, RIA)), 86255 (Fluorescent noninfectious agent antibody; screen, each antibody), or 86256 (Fluorescent noninfectious agent antibody; titer, each antibody), depending on how the lab performed the test.

Beginning January 1, you should report 86041 for the AChR binding antibody test, regardless of your lab method. “As a rule, you should not use a method-specific lab code when CPT^® provides an analyte-specific code for a test,” says William Dettwyler, MT AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Oregon.

Additional: Clinicians may order further antibody testing based on the results of the 86041 assay. In fact, labs may establish a reflex test for one or more of the other antibodies based on the level of AchR binding antibody. MuSK testing may be valuable when all other antibody tests are negative.

Bottom line: Testing for different antibodies may aid in diagnosis and in distinguishing different forms of MG, which can affect treatment plans. Report each individual test that your lab performs using the appropriate CPT^® 2024 immunology code.

Upgrade Microbiology Choices

CPT^® 2024 adds two new tests to the microbiology section, as follows:

Monkeypox testing: Although 87593 (Infectious agent detection by nucleic acid (DNA or RNA); orthopoxvirus (eg, monkeypox virus, cowpox virus, vaccinia virus), amplified probe technique, each) has been effective since July 26, 2022, you’ll find the code for the first time in the CPT^® 2024. The American Medical Association (AMA) released the code out of cycle to facilitate reporting the Centers for Disease Control and Prevention (CDC) nonvariola orthopoxvirus (NVO) real-time polymerase chain reaction (RT-PCR) test to help combat the spread of the disease.

Monkeypox is caused by a virus in the orthopoxvirus genus, which includes monkeypox virus, cowpox virus, vaccinia virus, and the eradicated variola virus, which caused smallpox. Infection typically results in a rash or skin lesions that shed the monkeypox virus.

Key: Code 87593 describes the CDC NVO test or other tests that fit the code descriptor. Depending on the assay performed, the findings may be for any virus in the orthopoxvirus genus, or for an individual species. Report one unit of 87593 for each unique amplified probe test for each general or specific orthopoxvirus assay.

Hepatitis D (delta): Code 87523 (Infectious agent detection by nucleic acid (DNA or RNA); hepatitis D (delta), quantification, including reverse transcription, when performed) describes a test to quantify the level of an infectious agent, hepatitis D (delta), in the patient blood specimen. Prior to addition of this code, labs may have reported this test using the nonspecific nucleic acid probe quantification method code 87799 (Infectious agent detection by nucleic acid (DNA or RNA), not otherwise specified; quantification, each organism).

The test quantifies the level of hepatitis D (delta) antigens, which are specific protein particles on the surface of the virus. Hepatitis D infection occurs only in patients with a current hepatitis B infection and may worsen the symptoms and may lead to liver damage or cancer. Measuring the hepatitis D viral load may help clinicians determine the appropriate treatment and monitoring regimen for a patient with hepatitis B.

Learn What Else is New

You’ll need to upgrade your administrative multianalyte assay with algorithmic analysis (MAAA) code for liver cancer biomarker testing starting January 1.

That’s because CPT^® 2024 deletes 0014M (Liver disease, analysis of 3 biomarkers (hyaluronic acid [HA], procollagen III amino terminal peptide [PIIINP], tissue inhibitor of metalloproteinase 1 [TIMP-1]), using immunoassays, utilizing serum, prognostic algorithm reported as a risk score and risk of liver fibrosis and liver-related clinical events within 5 years) and replaces it with new code 81517 code that has the same definition.

Clinicians may order this blood test to help assess liver status in patients at risk for chronic liver disease. The resulting score is referred to as an ELF (enhanced liver fibrosis) score. This test is used for screening and follow–up of patients with liver disease. The test is less invasive than a liver biopsy but provides comparable information relevant to the likelihood that the patient will develop liver fibrosis or liver-related clinical events within 5 years.

Chemistry: CPT^® 2024 adds 82166 (Anti-mullerian hormone (AMH)) for this hormone, which plays a role in sexual development and reproduction. Clinicians may test for AMH levels to diagnose intersex conditions in infants, or to evaluate testicular function and male fertility. The test may also be helpful in evaluating female fertility, polycystic ovary syndrome (PCOS), or menopausal status, among other clinical needs.

Before the addition of this code, labs may have reported the test using a method-specific test code such as 82397 (Chemiluminescent assay), which is a common method for measuring AMH.

Category III: Look to 0794T (Patient-specific, assistive, rules-based algorithm for ranking pharmaco-oncologic treatment options based on the patient’s tumor-specific cancer marker information obtained from prior molecular pathology, immunohistochemical, or other pathology results which have been previously interpreted and reported separately) for this sort of tumor analysis based on lab test results. This is not a lab test, but it uses the results of any lab or pathology tumor analysis that goes into the algorithmic analysis to determine the most promising pharmaco-oncologic treatment option.

“Category III codes are often created when the criteria for requesting a Category I code have not been met, but some information has been published about the procedure and there is enough anticipated usage that the service should be tracked,” explains Gregory Przybylski, MD, Chairman of Neuroscience at the New Jersey Neuroscience Institute, JFK University Medical Center in Edison, New Jersey.

The code may or may not be reimbursed by payers at present, but you should use the code, when appropriate, to aid in data gathering for the demand for the service. The Category III codes are temporary and may be converted to a Category I code if usage warrants.