Gastroenterology Coding Alert

It was the biggest gastroenterology coding question when should modifier -51 (multiple procedures) be used on a claim for multiple endoscopic procedures, and when should modifier -59 (distinct procedural service) be used? Over the past two years, though, many gastroenterology practices have been phasing out modifier -51. Some have started billing modifier -59 in its place; others no longer use a modifier in those situations. While the wide variation in coding suggests there is no national consensus on modifier -51, some practices have reported improved reimbursement after they stopped coding it.
CPT's Traditional Definition
Although many coders discontinued modifier -51, there has been no official change in policy from CPT or Medicare regarding either modifier. Modifier -51 should be used in the following coding situations, according to the American Medical Association publication Principles of CPT Coding:

multiple medical procedures performed at the same session by the same provider   
multiple, related operative procedures performed at the same session by the  same provider
 
operative procedures performed in combination at the same session, by the same provider, whether through the same or another incision or involving the same or different anatomy
 
a combination of medical and operative procedures performed at the same session by the same provider.
The distinction between modifier -51 and modifier -59 has never been very clear. According to the AMA, modifier -59 is intended to clearly designate instances when distinct and separate services are provided to a patient on a single date of service. It is a default modifier "to be used if no more descriptive modifier is available."
Carriers Manual Specifies Modifier -51
Medicare still calls for modifier -51 when describing its two payment rules for multiple procedures. Medicare Carriers Manual sections 4826 and 15038 describe the payment rules and modifiers for multiple procedures:
 
1. Standard Payment Rule for Multiple Surgeries: If two or more procedures with different endoscopic base codes (unrelated endoscopic procedures) are reported on the same day, the procedures should be listed on the claim in descending order based on their relative value units (RVUs).
 
No modifiers are needed when unrelated endoscopic procedures are reported under the standard payment rule for multiple surgeries. For example, if a colonoscopy by snare technique (45385, 45378 [endoscopic base code]) is performed on the same day as an upper gastrointestinal endoscopy (43235 [endoscopic base code]), the standard payment rule applies and no modifier is needed.
 
2. Special Payment Rule for Multiple Endoscopies: If two or more endoscopic procedures with the same endoscopic base code are reported on the same day, the procedures should be listed on the claim in descending order based on their RVUs. Modifier -51 should be attached to the lower-valued procedure(s).
 
An example of multiple endoscopic [...]