Gastroenterology Coding Alert

Time is a factor when choosing between 91037 and 91038.

When your physician's note suggests impedance and pH tests being performed together, you would look into the 9103x series of your CPT manual. Easy? Not quite. Take the following case in point.

Scenario: The motility specialist performs impedance + pH test for over an hour. The patient, who complains of frequent and painful heartburn, leaves the office with the catheter in place until the next day.

Dilemma: Can you bill 91038 by itself, or do you need to add 91034 at all?

The key is to understand what each code entails, but don't just base your choice on the obvious. You should give weight to Correct Coding Initiative (CCI) edits, too. These guidelines should keep you on the right track.

1. Turn To 91037-91038 For Impedance Catheter

When reporting esophageal function (impedance) tests, you would describe it using two codes:

• 91037 -- Esophageal function test, gastroesophageal reflux test with nasal catheter intraluminal impedance electrode(s) placement, recording, analysis and interpretation
• 91038 -- ...prolonged (greater than 1 hour, up to 24 hours)

Notice the descriptors for 91037 and 91038 depict time measurements, which means you should apply 91037 for testing that lasts up to one hour. If the monitoring lasts more than one hour, bill 91038 instead. Do not bill both codes for the same test. You should apply only a single code to report the session.

What happens: During an impedance test, the catheter enters the patient's body transnasally. This test measures bolus transit dynamics with either pH measurement or esophageal muscular function in the evaluation of symptoms including chest pain, swallowing difficulty, or chronic heartburn unresponsive to medication. Sometimes, physicians would perform these tests in combination with manometry or pH testing.

Both motility study (manometry) and esophageal function testing use a nasal catheter. However, the impedance probe is multi-purpose and measures more things than the motility test (91010, Esophageal motility [manometric study of the esophagus and/or gastroesophageal junction] study with interpretation and report; 2-dimensional data) or the gastroesophageal reflux test (91034, Esophagus, gastroesophageal reflux test; with nasal catheter pH electrode[s] placement, recording, analysis and interpretation).

2. Sole Code Describes Cather-Based pH Test

When a gastroenterologist provides an esophageal acid reflux test using either a disposable or a reusable nasal catheter, you would report 91034 says Linda Parks, MA, CPC, CMC, CMSCS, an independent coding consultant in Lawrenceville, Ga.

Pointer: CPT 91034 should be your go-to code regardless of how long the nasal catheter remains in place. Mostly, however, the physician will leave the catheter in place for about a day. In the past, you had to distinguish between standard and "extended" pH monitoring. Presently, only one code (91034) describes a catheter-based pH service.

On the other hand, if your gastroenterologist conducts pH testing using a Bravo capsule, you will turn to 91035 (Esophagus, gastroesophageal reflux test; with mucosal attached telemetry pH electrode placement, recording, analysis and interpretation) instead of 91034.

3. Beware What CCI Edits Say

The scenario describes both impedance and pH tests being performed in one session. If you think coding it is as easy as billing 91038 and 91034, you're wrong. Dodge a potential audit by looking into another important factor: CCI edits.

Edit alert: CPTs 91038 and 91034 are bundled codes. Check out the CCI edits table and you'll see 91034 described as the more extensive code. Since the 91038/91034 edit carries a modifier indicator of "0," you cannot override the edit by using modifier (i.e., modifier 59, Distinct procedural service).

For that reason, you would bill the given scenario with only 91034. Link 787.1 (Heartburn) to 91034 to describe the patient's condition.