Pathology/Lab Coding Alert

Question:  When our lab bills for PT ordered for a patient with unspecified chest pain, we get denials from Medicare. We don’t have the same problem when performing PTT with the same diagnosis. What is the problem, and how can we resolve it? 

Nebraska Subscriber

Answer: Presumably you’re reporting unspecified chest pain as 786.50 (Unspecified chest pain). The problem may be that your Medicare contractor hasn’t updated to the current National Coverage Determination (NCD). You should talk to your MAC, because 786.50 was added in 2012 as a “payable diagnosis” for PT (85610, Prothrombin Time).

Back story: Blood coagulation function can be assessed with Partial Thromboplastin Time (PTT), and Prothrombin Time (PT), among other tests. PTT assesses the intrinsic branch of the coagulation pathway, while PT assesses the extrinsic branch. The reasons for ordering the two tests can be very similar, including patients presenting with chest pain.

For some reason, the lab NCD for PT and PTT originally included 786.59 (Other chest pain) on the list of ICD-9 codes that showed medical necessity for the test, but only PTT (not PT) included 786.50 as a payable diagnosis.

However, the lab NCDs were updated in 2012, adding both 786.50 and 786.51 (Precordial pain) to the list of ICD-9 codes that show medical necessity for PT (85610). 

If you’re still receiving denials in these cases, you should contact your Medicare contractor and discuss the issue. You can find the PT NCD at www.cms.gov/medicare-coverage-database/details/ncd-details.aspx?NCDId=80&ncdver=1&bc=AAEAAAAAAAAA&.