GI Coding: Why Is Modifier 53 on the Medicare Physician Fee Schedule?

coding for colonoscopy

The Medicare Physician Fee Schedule (MPFS) includes special pricing for four colonoscopy codes when you append modifier 53 (Discontinued procedure). Here’s what you need to know about appending modifier 53 to these codes and the payment you can expect.

Compare Rates for Total and Discontinued Colonoscopies

Below are the four codes on the 2020 first quarter MPFS that have specific pricing when you append modifier 53. The rates shown are national rates. These rates are subject to quarterly changes, so always confirm the pricing for your date of service and for your specific geographic location.

G0105 (Colorectal cancer screening; colonoscopy on individual at high risk)
 Facility settingNonfacility setting
No modifier$192.72$339.60
Modifier 53$95.64$193.80
G0121 (Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk)
 Facility settingNonfacility setting
No modifier$193.44$340.32
Modifier 53$96.00$310.37
44388 (Colonoscopy through stoma; diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure))
 Facility settingNonfacility setting
No modifier$163.12$313.62
Modifier 53$81.20$183.70
45378 (Colonoscopy, flexible; diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure))
 Facility settingNonfacility setting
No modifier$193.08$339.96
Modifier 53$96.00$194.16

Medicare sources, such as MLN Matters ­MM9317 and Medicare Claims Processing Manual, Chapter 12, Section 30.1, state that Medicare will pay for an interrupted colonoscopy at a rate using half the value of the code inputs.

You can see in the tables above that the dollar amounts when you append modifier 53 are not half of the dollar amounts for the codes with no modifier. But if you look at the relative value units (RVUs) listed in the MPFS, you will see that the work RVUs in the modifier 53 rows are half of the work RVUs in the rows with no modifier. The facility practice expense (PE) RVUs are half or close to it. The malpractice RVUs are fairly close to half, but the nonfacility PE RVUs are farther from the halfway mark. That’s why the facility setting rates are closer to half than the rates in the nonfacility setting.

Get the Facts on When to Apply Modifier 53

Gastroenterology coders may recall that the MPFS started providing specific values for these colonoscopy codes with modifier 53 effective for dates of service Jan. 1, 2016, and later.

The motivating factor was that CPT® instructions changed the definition of incomplete colonoscopy starting in 2015. Before 2015, CPT® guidelines indicated an incomplete colonoscopy was one that did not evaluate the colon past the splenic flexure, according to MLN Matters MM9317. The article goes on to explain that physicians used to be instructed to report 45378-53 for an incomplete colonoscopy and got paid the same as for a sigmoidoscopy.

Starting in 2015, and still in 2020, the CPT® guidelines state, “When performing a diagnostic or screening endoscopic procedure on a patient who is scheduled and prepared for a total colonoscopy, if the physician is unable to advance the colonoscope to the cecum or colon-small intestine anastomosis due to unforeseen circumstances, report 45378 (colonoscopy) or 44388 (colonoscopy through stoma) with modifier 53 and provide appropriate documentation.”

The other two codes with special pricing, G0105 and G0121, are HCPCS Level II codes, which is why the CPT® guidelines don’t reference those G codes.

Anatomy tip: The new guidelines state that an incomplete colonoscopy does not reach the cecum or colon-small intestine anastomosis. The cecum is a pouch connected to where the small and large intestines join. This is significantly farther into the large intestine than the splenic flexure referenced in CPT® before 2015, as you can see in the image with this post.

What About You?

Do you wish more codes on the MPFS provided specific amounts for codes with modifier 53 appended? Or do you think it’s better for discontinued procedures to be priced on a case by case basis?


Deborah works on a wide range of TCI SuperCoder projects, researching and writing about coding, as well as assisting with data updates and tool development for our online coding solutions. Since joining TCI in 2004, she’s covered the ins and outs of coding for radiology, cardiology, oncology and hematology, orthopedics, audiology, and more.

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