Question: Our lab performed a basic metabolic panel with total calcium, and the physician ordered a repeat total calcium test later the same day based on an abnormal finding. How should we code the repeat test?
Answer: Because total calcium is part of the initial basic metabolic panel that your lab performed (80048, Basic metabolic panel [Calcium, total]), billing the stand-alone test may look to the payer like you’re unbundling.
That’s why you should append a modifier to the calcium test, 82310 (Calcium; total) when you bill for the test performed the same day as 80048.
Payer specific: Some payers may want you to report the second calcium test with modifier 91 (Repeat clinical diagnostic laboratory test), but some may expect 59 (Distinct procedural service). Ask your payer for direction regarding the preferred modifier.