When To Use Modifier -91

When To Use Modifier -91

Medical billing has certain nuances that billers should be aware of when submitting claims to insurance companies. One nuance is a modifier. A modifier adds additional information to a current procedural terminology code that the code itself does not present. Modifier 91 is frequently misused when doing medical billing.

Modifier 91 is used to report when multiple diagnostic tests are done during the same day. For example: If a patient is rushed into the emergency room and is given a stat glucose test which determines he has hypoglycemia, he will be given glucose gel. Then the emergency staff will need to test him fifteen to twenty minutes later to see if his glucose levels have stabilized.

If this hospital submitted a claim with two glucose tests and no modifier, one of them would be unpaid. If the hospital submitted a claim and one of the glucose tests had a modifier 91, this would tell the insurance company that the same test was done on the same day and is not a duplicate. By using modifier 91 in medical billing, multiple tests can be reimbursed.

When doing medical billing with modifier 91, there are many common misuses. This modifier should not be used in medical billing for tests that require serial measurements. This means, by definition, a certain test has to be done several times to compare measurements. Also, modifier 91 should not be used when a lab test is repeated due to specimen or equipment problems. It should only be used when multiple tests are required in order to test the health of the patient again.

When using modifier 91 in medical billing, many headaches can be saved. If this modifier is used it may prevent future phone calls to the insurance company and future claim resubmissions. Medical billing is a skilled process and with the use of modifier 91, this process can be streamlined.

View all Articles by: Melissa Clark, CCS-P