Pathology/Lab Coding Alert

Question: We are an independent lab, and we send out orders for molecular diagnostic testing to a reference laboratory. The reference lab bills us. How should we report the service to the patient's insurer?

Connecticut Subscriber

Answer: Use codes 83890-83912 (Molecular diagnostics ...) to report genetic testing that involves manipulating and investigating specific nucleic acid sequences to identify possible genetic disorders.

CPT instructs you to code separately for each procedure used in the genetic analysis. For example, you should report a procedure involving DNAisolation, restriction endonuclease digestion, electrophoresis and nucleic acid probe amplification as 83890 (... molecular isolation or extraction), 83892 (... enzymatic digestion), 83894 (... separation by gel electrophoresis [e.g., agarose, polyacrylamide]), and 83898 (... amplification of patient nucleic acid [e.g., PCR, LCR], single primer pair, each primer pair).

If your insurer allows pass-through billing (for a service not performed by you, but performed by an outside lab), you should report the appropriate code(s) 83890-83912 with modifier -90 (Reference [outside] laboratory). Modifier -90 indicates to your insurer that a party other than you, the reporting lab, performed the procedure.

Make certain that you meet your insurer's requirements for pass-through billing before you bill referred tests. For example, your lab (the referring lab) may bill Medicare for a clinical laboratory test performed by a reference laboratory only if you meet at least one of the following circumstances:

The referring lab is in a rural hospital.

The reference and referring labs are under the same ownership.

The referring lab does not refer more than 30 percent of its clinical lab test requests per year (not counting same-ownership referrals).

Also, you must include the name, address, and Clinical Laboratory Improvement Amendments certification number of the referring and reference laboratories on the claim. Medicare has specific pricing and payment rules depending on the carrier jurisdiction for the referring and reference labs. You can read more about Medicare's rules in sections 40.1 and 50.1 of the Medicare Claims Processing Manual, available on the Internet at http://www.cms.hhs.gov/manuals/pm_trans/R23CP2.pdf.