Pathology/Lab Coding Alert

Question: When a physician orders H. pylori IgG, IgA and IgM, we run three separate tests, each described by CPT 86677 . Do we need to report the multiple units with modifier -91 or -59?

North Carolina Subscriber

Answer: The appropriate modifier for this scenario would be -91 (Repeat clinical diagnostic laboratory test). In the simplest cases, modifier -91 is used when the same laboratory test is repeated on the same day during the course of patient treatment to obtain subsequent results. For example, if a patients blood gases are measured in the morning and again in the afternoon, report 82803 (Gases, blood, any combination of pH, pCO2, pO2, CO2, HCO3 [including calculated O2 saturation]) and 82803-91. However, modifier -91 is also appropriate when multiple laboratory tests that are reported with the same CPT code are performed for the same patient on the same date of service, even if each test is for a different analyte. In the example given, the lab carries out three Helicobacter pylori antibody tests (86677), one for IgG, one for IgA, and one for IgM. Report the first test without modifier -91 (86677), and each subsequent test with modifier -91 (two units of 86677-91).

There has been some confusion about the use of modifier -59 (Distinct procedural service) for clinical lab tests because some coders have understood this to describe only physician procedures. However, CMS states that modifier -59 is appropriate for reporting multiple clinical lab tests under some circumstances. Specifically, when repeat laboratory tests involve different anatomic sites, such as bacterial cultures taken from multiple lesion sites (e.g., 87070 and 87075), it would be more appropriate to use modifier -59 than -91.

The use of modifiers -91 and -59 is bound to be interpreted and applied in different ways by different payers and government contractors, so the provider should ask those sources for specific guidance.