An Overview of Colonoscopy Coding Guidelines

A screening colonoscopy should have no patient due amount for an insured patient, but if the physician does a diagnostic procedure (biopsy) or therapeutic procedure (removal of polyp), the procedure is no longer considered a screening.
In that case, using the correct modifiers and sequencing the diagnosis codes correctly can increase the likelihood that the payer will still process the service as a screening, but there are no guarantees.
Medicare charges co-insurance in that case, the amount of which will very gradually decrease to zero by 2030.

Screening colonoscopy is a service with first dollar coverage. A screening test with an A or B rating from the US Preventive Services Task Force, should have no patient due amount, since the Affordable Care Act (ACA) was passed. But, what if the surgeon or gastroenterologist takes a biopsy or removes a polyp? How is that billed, and with what modifiers and diagnoses? CodingIntel provides detailed medical coding resources to physicians and their staff to help them accurately code for their services, including colonoscopy coding guidelines with using CPT codes, modifiers PT and 33, and diagnosis coding. All of these are important.

Want unlimited access to CodingIntel's online library?

Including updates on CPT^® and CMS coding changes for 2023

Join Today

How to code for screening colonoscopies, what modifiers are needed and what diagnosis codes to assign can be challenging for physicians. An area of particular confusion is screening colonoscopies converted to a diagnostic or therapeutic colonoscopy.

To complicate the issue, Medicare uses different procedure codes than other payers for screening and a different modifier for screening procedures that become diagnostic or therapeutic. This article from CodingIntel about colonoscopy coding guidelines, will help physicians, coders and billers select accurate procedure and diagnosis codes for colonoscopy services.

Members can watch this brief overview, and download the slides for reference.Members, login to watch the video. Not a member? Learn more about membership.

What is the Difference between a Screening Test and a Diagnostic Colonoscopy?

A screening test is a test provided to a patient in the absence of signs or symptoms based on the patient’s age, gender, medical history and family history according to medical guidelines. It is defined by the population on which the test is performed, not the results or findings of the test. A diagnostic test is done in response to a sign or symptom, to investigate and diagnosis a condition. A patient with rectal bleeding and anemia who is has a colonscopy is having a diagnostic colonoscopy.

As such, “screening” describes a colonoscopy that is routinely performed on an asymptomatic person for the purpose of testing for the presence of colorectal cancer or colorectal polyps. Whether a polyp or cancer is ultimately found does not change the screening intent of that procedure.

[1]

As part of the Affordable Care Act (ACA), Medicare and third-party payers are required to cover services given an A or B rating by the U.S. Preventive Services Task Force (USPSTF) without a co-pay or deductible. That is, the patient has no patient due amount. However, diagnostic colonoscopy is a test performed as a result of an abnormal finding, sign or symptom. Medicare does not waive the co-pay and deductible when the intent of the visit is to perform a diagnostic colonoscopy. Medicare waives the deductible but not the co-pay when a procedure scheduled as a screening is converted to a diagnostic or therapeutic procedure.

Confounding this issue is the term “surveillance colonoscopy”—one performed at more frequent intervals than every ten years because the patient has a personal history of colonic polyps. Should this be billed as screening (in the absence of current signs/symptoms) or diagnostic, because it is being performed because of the personal history of the patient? Neither CPT^® nor CMS address this directly, but I will give my recommendations below, in Clinical Scenario five, at the end of this article. In my experience, surveillance is another word used by clinicians for screening. And, see the article on diagnosis coding for screening on CodingIntel; it provides references from the Coding Clinic.

Two Sets of Procedure Codes Used for Screening Colonoscopy:

CPT^® code 45378

Colonoscopy, flexible, proximal to splenic flexure; diagnostic, with or without collection of specimen(s) by brushing or washing, with or without colon decompression (separate procedure)

and

Healthcare Common Procedural Coding System (HCPCS) codes G0105 and G0121

G0105 colorectal cancer screening; colonoscopy on individual at high risk)

G0121 (colorectal cancer screening; colonoscopy on individual not meeting the criteria for high risk.

Why two sets of codes in coding colonoscopy guidelines?

The Centers for Medicare and Medicaid Services (CMS) developed the HCPCS codes to differentiate between screening and diagnostic colonoscopies in the Medicare population.

Common diagnosis codes for colorectal cancer screening include:

Z12.11 (encounter for screening for malignant neoplasm of colon)
Z80.0 (family history of malignant neoplasm of digestive organs)
Z86.010 (personal history of colonic polyps).

Clinical scenario one:

A 70-year-old Medicare patient calls the surgeon’s office and requests a screening colonoscopy. The patient’s previous colonoscopy was at 59-years old, and was normal. The patient has no history of polyps or colorectal cancer and none of the patient’s siblings, parents or children has a history of polyps or colorectal cancer. The patient is eligible for a screening colonoscopy. Reportable procedure and diagnoses include:

G0121, colorectal cancer screening; colonoscopy on individual not meeting the criteria for high risk
Z12.11, encounter for screening for malignant neoplasm of colon

The HCPCS code is the correct code to use—not the CPT^® code—because the patient is a Medicare patient. Additionally, G0121 is selected because the patient is not identified as high risk.

HCPCS and CPT^® screening colonoscopy codes
HCPCS/CPT^® code	Description
45378	Colonoscopy
G0105	Colorectal cancer screening; colonoscopy on individual at high risk
G0121	Colorectal cancer screening; colonoscopy on individual not meeting the criteria for high risk

Common colorectal screening diagnosis codes
ICD-10-CM	Description
Z12.11	Encounter for screening for malignant neoplasm of colon
Z80.0	Family history of malignant neoplasm of digestive organs
Z86.010	Personal history of colonic polyps

E/M Service Prior to a Screening Colonoscopy

Typically, procedure codes with 0, 10 or 90-day global periods include pre-work, intraoperative work, and post-operative work in the Relative Value Units (RVUs) assigned. As a result, CMS’ policy does not allow for payment of an Evaluation and Management (E/M) service prior to a screening colonoscopy. In 2005, the Medicare carrier in Rhode Island explained the policy this way:

“Medicare does not cover an E/M prior to a screening colonoscopy. An item or service must have a defined benefit category in the law to be covered under Medicare. For example, physicians services are covered under section 1861(s)(1) of the Social Security Act. However, section 1862(a)(1)(A) states that no payment may be made for items or services that are not reasonable and necessary for the diagnosis or treatment of an illness or injury or to improve the functioning of a malformed body member.

In addition, section 1862(a)(7) prohibits payment for routine physical checkups. These sections prohibit payment for routine screening services, those services furnished in the absence of signs, symptoms, complaints, or personal history of disease or injury. … While the law specifically provides for a screening colonoscopy, it does not also specifically provide for a separate screening visit prior to the procedure. The Office of General Counsel (OGC) was consulted to determine if sections 1861(s)(2)(R) and 1861(pp) could be interpreted to allow separate payment for a pre- procedure screening visit in addition to the screening colonoscopy. The OGC advises that the statute does not provide for such a preprocedure screening visit.”

[2]

Medicare defines an E/M prior to a screening colonoscopy as routine, and thus non-covered. However, when the intent of the visit is a diagnostic colonoscopy an E/M prior to the procedure ordered for a finding, sign or symptom is a covered service.

Third-party payers that do not follow Medicare guidelines may reimburse a surgeon for an E/M service prior to a screening colonoscopy. There are no CPT guidelines for how to select a code based on medical decision making for a screening procedure. One option is to use time.

Screening Colonoscopy for Medicare Patients

Report a screening colonoscopy for a Medicare patient using G0105 (colorectal cancer screening; colonoscopy on individual at high risk) and G0121 (colorectal cancer screening; colonoscopy on individual not meeting the criteria for high risk).

Medicare beneficiaries without high risk factors are eligible for screening colonoscopy every ten years. Beneficiaries at high risk for developing colorectal cancer are eligible once every 24 months. Medicare considers an individual at high risk for developing colorectal cancer as one who has one or more of the following:

A close relative (sibling, parent or child) who has had colorectal cancer or an adenomatous polyp.
A family history of familial adenomatous polyposis.
A family history of hereditary nonpolyposis colorectal cancer.
A personal history of adenomatous polyps.
A personal history of colorectal cancer.
Inflammatory bowel disease, including Crohn’s Disease, and ulcerative colitis.

[3]

To report screening colonoscopy on a patient not considered high risk for colorectal cancer, use HCPCS code G0121 and diagnosis code Z12.11 (encounter for screening for malignant neoplasm of the colon). To report screening on a Medicare beneficiary at high risk for colorectal cancer, use HCPCS G0105 and the appropriate diagnosis code that necessitates the more frequent screening.

Clinical scenario two:

A Medicare patient with a history of Crohn’s disease presents for a screening colonoscopy. Her most recent screening colonoscopy was 25 months ago. No abnormalities are found. Reportable procedures and diagnoses include:

G0105, Colorectal cancer screening; colonoscopy on individual at high risk
Z12.11, Encounter for screening for malignant neoplasm of colon
K50.80, Crohn’s disease of both small and large intestine without complications

Common ICD-10 diagnosis codes indicating high risk
Z85.038	Personal history of other malignant neoplasm of large intestine
Z85.048	Personal history of other malignant neoplasm of rectum, rectosigmoid junction, and anus
Z80.0	Family history of malignant neoplasm of digestive organs
Z86.010	Personal history of colonic polyps

Screening Colonoscopy for Medicare Patients that becomes Diagnostic or Therapeutic

It is not uncommon to remove one or more polyps at the time of a screening colonoscopy. Because the procedure was initiated as a screening the screening diagnosis is primary and the polyp(s) is secondary. Additionally, the surgeon does not report the screening colonoscopy HCPCS code, but reports the appropriate code for the diagnostic or therapeutic procedure performed, CPT^® code 45379—45392.

Colonoscopy CPT^® codes
CPT^® Code	Descriptor
45378	Colonoscopy; flexible, diagnostic, including collection of specimen (s) by brushing or washing, when performed(separate procedure)
45379	with removal of foreign body (s)
45380	with biopsy, single or multiple
45381	with directed submucosal injection(s), any substance
45382	with control of bleeding, any method
# 45388	with ablation of tumor(s), polyp(s), or other lesion(s) (includes pre- and post-dilation and guide wire passage, when performed)

45384	with removal of tumor(s), polyp(s), or other lesion(s) by hot biopsy forceps
45385	with removal of tumor(s), polyp(s), or other lesions by snare technique
45386	with transendoscopic balloon dilation
45389	with endoscopic stent placement (includes pre- and post-dilation and guide wire passage, when performed)
#45390	with endoscopic mucosal resection
45391	with endoscopic ultrasound examination limited to the rectum, sigmoid, descending, transverse, or ascending colon and cecum, and adjacent structures
45392	with transendoscopic ultrasound guided intramural or transmural fine needle aspiration/biopsy(s), includes endoscopic ultrasound examination limited to the rectum, sigmoid, descending, transverse or ascending colon and cecum, and adjacent structures
45393	with decompression (for pathologic distention) (eg, volvulus, megacolon), including placement of decompression tube, when performed
# 45398	with band ligation(s) (eg, hemorrhoids)

Modifier PT

CMS developed the PT modifier to indicate that a colonoscopy that was scheduled as a screening was converted to a diagnostic or therapeutic procedure. The PT modifier (colorectal cancer screening test, converted to diagnostic test or other procedure) is appended to the CPT^® code.

Add modifier PT to the CPT^® codes above to indicate that a scheduled screening colonoscopy was converted to a diagnostic or therapeutic procedure. Modifier PT should be added to the anesthesia service as well. This informs Medicare that it was a service performed for screening and the patient will not be charged a deductible. There will be a co-pay due.

Screening Colonoscopy for Non-Medicare Patients

When reporting a screening colonoscopy on a non-Medicare patient, report CPT^® code 45378 and use the appropriate screening diagnosis code. As a result of the ACA, Patients covered by a group insurance policy that was purchased or renewed after September 2010 will have no co-pay or deductible, unless the plan applied for grandfathered status.

Clinical scenario three:

A 52-year-old patient calls the surgeon’s office and requests a screening colonoscopy. The patient has never had a screening colonoscopy. The patient has no history of polyps and none of the patient’s siblings, parents or children has a history of polyps or colon cancer. The patient is eligible for a screening colonoscopy. Reportable procedure and diagnoses include:

45378, Colonoscopy, flexible, proximal to splenic flexure; diagnostic, with or without collection of specimen(s) by brushing or washing, with or without colon decompression (separate procedure)
Z12.11, Encounter for screening for malignant neoplasm of colon

Screening Colonoscopy for Non-Medicare Patients that becomes Diagnostic or Therapeutic

When a screening colonoscopy converts to a diagnostic or therapeutic procedure for a non-Medicare patient, the surgeon must document that the intent of the procedure was screening in order for the patient’s insurance to process the claim without out-of-pocket expense in accordance with the ACA. CPT^® developed the 33 modifier for preventive services, “when the primary purpose of the service is the delivery of an evidence-based service in accordance with a US Preventive Services Task Force A or B rating in effect and other preventive services identified in preventive services mandates (legislative or regulatory), the service may be identified by adding 33 to the procedure.” For example, if a surgeon performing a screening colonoscopy finds and removes a polyp with a snare, use CPT^® code 45385 and append modifier 33 to the CPT^® code.

Clinical scenario four:

The same 52- year-old patient from the previous example has had an abnormal finding during their screening colonoscopy. The surgeon removes a polyp with a snare technique. Reportable procedure and diagnoses include:

45385-33, Colonoscopy, flexible, proximal to splenic flexure; with removal of tumor(s), polyp(s), or other lesions by snare technique
Z12.11, Encounter for screening for malignant neoplasm of colon
K63.5 Polyp of the colon

In this case, report Z12.11 as the primary diagnosis to indicate it was scheduled as a screening test and K63.5 as the secondary diagnosis. In addition, modifier 33 tells the payer that the primary purpose of the test was screening, in accordance with evidence based practice as identified by USPSTF.

Diagnosis Code Ordering is Important for a Screening Procedure turned Diagnostic

When the intent of a visit is screening, and findings result in a diagnostic or therapeutic service, the ordering of the diagnosis codes can affect how payers process the claim. There is considerable variation in how payers process claims, and the order of the diagnosis code may affect whether the patient has out–of-pocket expense for the procedure. The appropriate screening diagnosis code should be placed in the first position of the claim form and the finding or condition diagnosis in the second position. It is important to verify a payer’s reporting preference to avoid payment denials.

There are two sets of procedure codes that describe colonoscopy services. Additionally, there are different preventive service modifiers for Medicare and other third-party payers. The order of diagnosis coding can affect how a payer processes the claim and whether there is an out-of-pocket expense for the patient. Mastering the coding for each payer may result in lower claims processing costs, quicker payments, and fewer patient complaints.

Clinical scenario five:

At a routine screening, a patient is found to have an adenomatous polyp. The surgeon recommends that the patient return for a surveillance colonoscopy in three years. (The USPSTF recommendations do not address frequency of this repeat surveillance. The American Cancer Society does have recommendations.

[4]

Is this test diagnostic or screening? How it is coded will determine the patient due amount. I suggest reporting the service with modifier 33.

Modifier 33–Preventive Services: when the primary purpose of the service is the delivery of an evidence based service in accordance with a USPSTF A or B rating in effect and other preventive services identified in preventive services mandates (legislative or regulatory), the service may be identified by adding 33 to the procedure.

When reporting the diagnosis code, I would suggest reporting Z12.11 (encounter for screening for malignant neoplasm of the digestive organs) and Z86.010 (personal history of colonic polyps) second. The patient will probably need to appeal this to their insurance company. See the CodingIntel article “Diagnosis coding for screening colonoscopy” for more detail.

Additional Resources

Procedure Coding for Colonoscopies

Want unlimited access to CodingIntel's online library?

Including updates on CPT^® and CMS coding changes for 2023

Join Today

Footnotes

[1] “Coverage of Colonoscopies Under the Affordable Care Act’s Prevention Benefit,” September 2012 The Henry Kaiser Family Foundation

[2] Evaluation & Management Visit Prior to a Colonoscopy Medicare Part B Bulletin BCBS of AR: Feb 1, 2005

[3] http://www.cms.gov/Regulations-and-Guidance/Guidance/Manuals/Internet-Only-Manuals-IOMs.html, Publication 100-04, Chapter 18, Section 60.3

[4] www.cancer.org/cancer/moreinformation/colorectal-cancer-early-detection-acs-recommendations

All specific references to CPT^® (Current Procedural Terminology) codes and descriptions are © 2020 American Medical Association. All rights reserved. CPT^® is a registered trademark of the American Medical Association.