Pathology/Lab Coding Alert

Question: Our pathologist performs a flow cytometry cancer study looking at CD45, CD34 and CD3. Our billing department says we should use a modifier to indicate that we have done a "repeat test" for the technical portion of this study. Should this be modifier 59 or 91?


Texas Subscriber
Answer: You should not use either modifier - 91 (Repeat clinical diagnostic laboratory test) or 59 (Distinct procedural service).

The proper way to code the study you describe is as follows:
   For the technical component of the first marker, report 88184 (Flow cytometry, cell surface, cytoplasmic or nuclear marker, technical component only; first marker).
   Then report 88185 x 2 for the technical component of the two additional markers (+88185, ... each additional marker [list separately in addition to code for first marker]).

 For the pathologist's interpretation of the three markers included in this flow-cytometry study, use 88187 (Flow cytometry, interpretation; 2 to 8 markers). Although your billing department seems to consider 88185 a "repeat test" worthy of a modifier, that is not the case. Code 88185 is an add-on code that you must report in addition to 88184 whenever a flow-cytometry panel includes more than one marker. You should report 88185 for each marker beyond one because the code states "each additional marker."