Tests Performed More Than Once on the Same Day

100.5.1 - Tests Performed More Than Once on the Same Day (Rev. 1, 10-01-03) PM AB-98-7 When it is necessary to obtain multiple results in the course of treatment, the modifiers 59 or 91 are used to indicate that a test was performed more than once on the same day for the same patient. The 91 modifier is used for laboratory tests paid under the clinical laboratory fee schedule. These modifiers may be used to indicate that a test was performed more than once on the same day for the same patient, only when it is necessary to obtain multiple results in the course of treatment. These modifiers may not be used when tests are rerun to confirm initial results; due to testing problems with specimens and equipment; or for any other reason when a normal, one-time, reportable result is all that is required. These modifiers may not be used when there are standard HCPCS codes available that describe the series of results (e.g., glucose tolerance tests, evocative/suppression testing, etc.). These modifiers may be used only for laboratory tests paid under the clinical laboratory fee schedule. Improper use of modifiers is likely to indicate a fraudulent or abusive circumstance. When informing laboratories of the availability of modifiers, A/B MACs (B) are to emphasize that these modifiers have very narrow application and that any evidence of excessive use will be referred to A/B MAC (A) or (B) Program Integrity Unit for further review.