Pathology/Lab Coding Alert

Question: Our lab performs a molecular diagnostics "array" test that involves more than 1,000 probes. Should we report multiple units of 88386 to account for the large number of probes?

Ohio Subscriber

Answer: You should not report multiple units of 88368 (Array based evaluation of multiple molecular probes; 251 through 500 probes) or any other array code to bill for a particularly large array. You may need to use an unlisted code, such as 88399 (Unlisted surgical pathology procedure) instead.

CPT provides the following three codes for molecular diagnostics arrays:

• 88384 -- Array based evaluation of multiple molecular probes; 11 through 50 probes

• 88385 -- ... 51 through 250 probes

• 88386 -- ... 251 through 500 probes.

Not additive: Don't mistake the number ranges for "additional" probes -- if you do, you might erroneously list 88384 for the first 50 probes and 88385 for additional probes 51 through 250.

Instead: Each of these three codes stands alone.

You should select one of the three codes based on the number of probes in the array you're coding. For instance, if the array has 30 probes, list 88384, but if it has 300 probes, list 88386.

Problem: What do you do if your array has fewer than 11 or more than 500 probes?

Solution: A CPT note following 88386 instructs, "for preparation and analysis of less than 11 probes, see 83890-83914." That means you should use the molecular diagnostics codes for an array with 1-10 probes.

For larger arrays with more than 500 probes, the AMA suggests reporting unlisted code 88399 (Unlisted surgical pathology procedure), according to Pathology Service Coding Handbook, version 10.1 by Dennis Padget, MBA, CPA, FHFMA, published quarterly by DLPadget Enterprises Inc.