Laboratory Question for the Week of March 24, 2025

Question:

A pathology lab is performing an immunofluorescent study on a skin biopsy to evaluate immunoglobulin deposits. They’re using fluorescent-tagged antibodies for IgG, IgM, and C3, with examination under fluorescent microscopy. I understand that 88346 would be reported for the initial study, but if they also perform an additional antibody stain for fibrinogen, how would this be reported?

Answer:

As of January 1, 2016, initial immunofluorescent studies may be reported using code 88346 and additional antibody stain procedures with add-on code +88350. Both involve introducing fluorescent-tagged antibodies. The specific ones used depend on the tissue being examined and the suspected diagnosis, but may include IgG, IgM, IgA, C3, C4, C1q, properdin, fibrin, fibrinogen, and albumin. The specimen is examined under fluorescent microscopy to assess the intensity, pattern, and distribution of immunoglobulins.

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