Pathology/Lab Coding Alert

Question: Our lab performs antibody testing for ASCA and ANCA to establish a differential diagnosis between Crohn’s disease and ulcerative colitis for patients with indeterminate colitis. What procedure and diagnosis codes should we report?  

Codify Subscriber

Answer: First, you should check to see if your payer covers the anti-saccaromyces cerevisiae antibodies (ASCA) test and the anti-neutrophil cytoplasm antibodies (ANCA) test for differential diagnosis of Crohn’s disease (CD) and ulcerative colitis (UC). If so, they probably provide specific coverage information that will help you with your claim.

That said, some possible CPT® codes you might report for the test(s), depending on the lab method used, include the following:

• 83516 — Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, multiple step method

• 83518 — … qualitative or semiquantitative, single step method (e.g., reagent strip)

• 83519 — … quantitative, by radioimmunoassay (e.g., RIA)

• 83520 — … quantitative, not otherwise specified

• 88347 — Immunofluorescent study, each antibody; indirect method.

Because you state that the testing is to distinguish between UC and CD, the most appropriate ICD-9 code for the known patient condition is probably 558.9 (Other and unspecified noninfectious gastroenteritis and colitis), although you’ll need to select the appropriate code based on the ordering physician’s documentation. Code 558.9 crosswalks to ICD-10 code K52.9 (Noninfective gastroenteritis and colitis, unspecified) for unspecified inflammatory bowel disease.