Pathology/Lab Coding Alert

Master immunology code additions.

With 15 new codes for immunology tests in CPT^® 2022, you have some preparation to do. If you miss the update, you might find yourself abusing less-specific codes such as 86255 (Fluorescent noninfectious agent antibody; screen, each antibody) or 83516 (Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, multiple step method) and facing payer rejections.

Coder tip: You’ll need to pay attention to the units described by the new immunology codes when you start to use them next year. In some cases, you’ll report one unit of the code for each antibody (Ab), but in other cases you’ll bill one unit for each immunoglobulin antibody class.

Read on to let our experts walk you through more details you need to know about the changes.

Distinguish ANCA Screen and Titer

CPT^® 2022 adds the following two new codes for antineutrophil cytoplasmic antibody (ANCA):

• 86036 (Antineutrophil cytoplasmic antibody (ANCA); screen, each antibody)
• 86037 (… titer, each antibody)

Prior to the addition of these codes, your lab would have reported an ANCA test using the code for leukocyte antibodies (86021, Antibody identification; leukocyte antibodies), because neutrophils are a type of leukocyte.

Problem: Because the 86021 definition states “antibodies,” you could report just one unit of the code even if the lab was testing for ANCA along with other leukocyte antibodies. Additionally, you could report just one unit of 86021 when the lab identified perinuclear-ANCA (P-ANCA) and cytoplasmic ANCA (C-ANCA) staining patterns. Clinicians often order both P-ANCA and C-ANCA because the results help distinguish between different types of autoimmune disorders.

Solution: “Code 86036 is a welcome addition because the new code states, ‘each antibody,’ meaning that you can report one unit of the code for P-ANCA and one unit for C-ANCA,” says William Dettwyler, MT-AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore.

Titer: When the lab performs the ANCA screen, the lab may reflex to a separate titer test for each antibody identified, such as P-ANCA and C-ANCA. The titer quantifies the level of each antibody present in the specimen, and you should report each titer with new code 86307.

Test Antibodies for NMO and Parkinson’s

You’ll find the following new specific codes in CPT^® 2022 for antibody tests related to conditions such as neuromyelitis optica (NMO) and multiple sclerosis (MS):

• 86051 (Aquaporin-4 (neuromyelitis optica [NMO]) antibody; enzyme-linked immunosorbent immunoassay (ELISA))
• 86052 (… cell-based immunofluorescence assay (CBA), each)
• 86053 (… flow cytometry (ie, fluorescence-activated cell sorting [FACS]), each)
• 86362 (Myelin oligodendrocyte glycoprotein (MOG-IgG1) antibody; cell-based immunofluorescence assay (CBA), each)
• 86363 (… flow cytometry (ie, fluorescence-activated cell sorting [FACS]), each)

Codes 86051-86053 describe tests for aquaporin-4 (AQP4) antibody using three different lab methods. The antibody is a key marker for NMO, which is an uncommon autoimmune disease characterized by optic nerve and possibly brain stem and spinal cord involvement. Clinically, the condition may be misdiagnosed as MS.

Units: These three codes indicate that a single unit represents identification of one antibody by using the singular, “antibody,” and stating, “each.” The most common antibody immunoglobulin (Ig) class targeted for this test is aquaporin-4 IgG antibody (AQP4-IgG), which represents one unit of the test code. AQP4-IgG is present in a large percentage of NMO patients, but not MS patients, so clinicians may consider a positive result as a marker for NMO.

3 methods, 3 codes: Labs may perform an AQP4-IgG test using an enzyme-linked immunosorbent immunoassay (ELISA), which you should report as 86051, or by two other methods. Clinicians consider the cell-based immunofluorescence assay (CBA) (86052) to be the gold standard for this test because it has higher specificity and sensitivity. Fluorescence-activated cell sorting [FACS] by flow cytometry (86053) may be more sensitive at low specimen antibody levels.

Old way: Prior to the addition of these codes, labs may have reported the 86051 test using a code such as 83516, and the 86052 and 86053 tests using a code such as 86255.

MOG-IgG1: The two new codes for Myelin oligodendrocyte glycoprotein (MOG-IgG1) antibody, 86362 and 86363, represent tests using the same methods described in 86052 (CBA) and 86053 (FACS using flow cytometry). Clinicians frequently order one of these MOG-IgG1 antibody tests following a negative AQP4 antibody test to help distinguish NMO from a similar condition called MOG-encephalomyelitis (MOG-EM).

Recall COVID Antibody Tests

Although the following three codes are new to the CPT^® 2022 manual, they’ve been active codes since late 2020 in response to the COVID-19 public health emergency:

• 86408 (Neutralizing antibody, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (coronavirus disease [COVID-19]); screen)
• 86409 (… titer)
• 86413 (Severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) (coronavirus disease [COVID-19]) antibody, quantitative)

Unlike other SARS-CoV-2 antibody codes, 86413 allows labs to measure a patient’s relative level of antibodies in response to a previous SARS-CoV-2 infection, according to Tim Stenzel, MD, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health. Quantitative measurement of different antibody classes may aid in understanding adaptive immune response to SARS-CoV-2 in patients.

Neutralizing Ab: Codes 86408 and 86409 describe tests to screen for the presence (86408) or measure the level (86409) of neutralizing antibody(ies) to SARS-C0V-2. “These tests determine if antibodies present in a patient specimen can directly block infection of cells expressing the viral entry receptor on their surface,” according to CPT^® Assistant Special August, 2020 Edition.

Results of these neutralizing antibody tests may help assess the efficacy of vaccines and identify optimal convalescent plasma donors, according to William Morice, II, MD, PhD, president of Mayo Clinic Laboratories.

Greet Other Specific Ab Codes

CPT^® 2022 also adds the following specific antibody test codes to the immunology section:

• 86015 (Actin (smooth muscle) antibody (ASMA), each)
• 86231 (Endomysial antibody (EMA), each immuno­globulin (Ig) class)
• 86258 (Gliadin (deamidated) (DGP) antibody, each immunoglobulin (Ig) class)
• 86364 (Tissue transglutaminase, each immunoglobulin (Ig) class)
• 86381 (Mitochondrial antibody (eg, M2), each)
• 86596 (Voltage-gated calcium channel antibody, each)

Note units: Each of these codes designates the unit of service as each antibody, or each immunoglobulin (Ig) class. Make a note of that information in the code descriptors and make sure you use the codes accordingly.