Pathology/Lab Coding Alert

Question: Our lab performs a B-cell gene rearrangement test by PCR with a series of primers specific for immunoglobulin heavy chain, kappa light chain, and lambda light chain genes. Should the pathologist bill 83912 or 83912 x 3 for the interpretation?

South Carolina Subscriber

Answer: The pathologist should bill one unit of 83912 (Molecular diagnostics; interpretation and report). Code 83912 is part of the molecular diagnostics family (83890-83913) used for analysis of nucleic acids, usually to diagnose genetic disorders. Each of these codes describes a separate technique, such as nucleic acid extraction (83890 or 83891), separation by gel electrophoresis (83894), or gene amplification, such as polymerase chain reaction (PCR) (83898). You code a molecular diagnostics test or panel by listing the codes for each of the steps.

You might need to report multiple units of some steps in the panel. In your example, you amplify three genes by PCR, so you would report three units of 83898 (Molecular diagnostics; amplification, target, each nucleic acid sequence). The code definition specifies that the unit of service is "each nucleic acid sequence," so you are justified to report one unit of 83898 for each of the three nucleic acid sequences: immunoglobulin heavy chain, kappa light chain, and lambda light chain.

Single interpretation: When the pathologist reviews the molecular diagnostics test or panel (in this case, a B-cell gene rearrangement test) and provides an interpretation or diagnosis, you should report one unit of 83912. The pathologist is providing an interpretation of the entire series of steps that comprise the entire test, not each individual step or nucleic acid sequence.

Watch for modifier: Medicare lists 83912 on the clinical lab fee schedule (CLFS) without a modifier and on the physician fee schedule (PFS) with modifier 26 (Professional component). If a pathologist (physician) performs the 83912 service, you should bill it with modifier 26 and receive payment from the PFS, which has a higher payment rate.