Gastroenterology Coding Alert

Question: If our gastroenterologist is performing an impedance test for gastroesophageal reflux disease, what is the basis on which I should select 91037 or 91038? Should I report 91037 for the first hour of testing and then use 91038? Also, if he is performing an impedance test and a pH test together, can I report both he service separately?

Codify Subscriber

Answer: When your gastroenterologist is performing an impedance test to check the muscular contractions of the esophageal walls (impedance actually examines for abnormal fluid transport fluid coming up from the stomach backwards, or not going down properly), you will report this service using the CPT^® codes, 91037 (Esophageal function test, gastroesophageal reflux test with nasal catheter intraluminal impedance electrode[s] placement, recording, analysis and interpretation) or 91038 (...prolonged [greater than 1 hour, up to 24 hours]). You will choose between the two codes only on the basis of time that your gastroenterologist spent in performing the procedure or in analysis and interpretation of the results.

If the time spent by your clinician was less than one hour, you will report the impedance test with 91037. If he spent more than an hour (up to 24 hours) you will report the service with 91038. You should not report 91037 for the first hour of service and then follow it up with 91038 for the service provided beyond one hour. Instead, if the total time spent by your clinician is more than one hour, you will report the entire service only with 91038.

If your clinician is performing a pH test, you will report this service with 91034 (Esophagus, gastroesophageal reflux test; with nasal catheter ph electrode[s] placement, recording, analysis and interpretation). When your clinician is performing an impedance test and a pH test together, you will have to follow Correct Coding Initiative (CCI) edits that bundle 91037 and 91038 into 91034. As CCI bundles these codes with the modifier '0' you cannot report them together under any circumstances. In such a case scenario, you'll have to resort to only reporting 91038 and not report the pH test separately, reflecting what is usually higher reimbursement for the 24-hour impedance test compared to the pH test. For private payers, it is important to know if they follow the same CCI edit or might pay separately for the two tests; if in doubt, bill 91038 first and 91034 second with a 59 modifier to indicate these were separate tests.