Harvard Pilgrim would like to provide clarification regarding appropriate and inappropriate use of modifier 91 (repeat clinical diagnostic laboratory test). Modifier 91 should be appended only to services in the laboratory code range of CPT 80047-89398. It is appropriate to use modifier 91 when the same laboratory test is repeated on the same patient, on the same day, to obtain subsequent test results. Multiple same-day laboratory tests (such as CPT 87804) should be reported twice because two separate, distinct analyses are performed, providing two separate test results. For Harvard Pilgrim, these same-day laboratory tests should be billed on one line with the number of units representing the number of services provided.
Modifier 91 is not appropriate when laboratory tests are rerun because of testing problems, equipment error or malfunction, or when a laboratory test is repeated to confirm initial results. It should also not be reported when the primary CPT code, by definition, indicates that a series of tests is to be obtained.
For more information, please refer to Harvard Pilgrim’s Laboratory and Pathology Payment Policy.