2021 ASC Coding Tips: Screening vs. Diagnostic Colonoscopies

By Mandeara Frye, RHIA, CPC, CPMA, CASCC, Director of Coding

Understanding when a colonoscopy is a screening or diagnostic procedure is critical not only for accurate code selection but also for the billing process since patient benefits vary for each service. This month, we’ll review the common criteria for screenings and how to properly code both screening and diagnostic colonoscopies.

Screening Criteria

The American Cancer Society recommends individuals who are at average risk of colorectal cancer start regular screenings at the age of 45. Average risk means those people who do not have a personal history of colon cancer, polyps, or inflammatory bowel disease or a family history of colorectal cancer. Those who have a personal or family history are considered high risk and may need to begin screening before age 45, depending on their history.

Medicare covers an average risk screening colonoscopy once every 10 years, whereas high-risk screenings are covered once every 24 months. If the colonoscopy results are normal, there is no cost to the patient for this service. If a polyp or other pathology is found during the encounter and is treated, then the patient may be responsible for a 20% co-insurance and/or a co-pay but would not be responsible for the deductible. For patients with commercial insurance, it’s important to verify screening benefits since they may have specific coverage requirements concerning age and frequency.

The codes for screenings include:

Diagnoses

• Z12.11 – Encounter for screening for malignant neoplasm of colon
• Z85.038 – Personal history of other malignant neoplasm of large intestine
• Z86.010 – Personal history of colonic polyps
• Z80.0 – Family history of malignant neoplasm of digestive organs

Medicare Procedure Codes

• G0121 – Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk
• G0105 – Colorectal cancer screening; colonoscopy on individual at high risk
• G0104 – Colorectal cancer screening; flexible sigmoidoscopy

Note: High versus low risk is not a factor for a screening sigmoidoscopy.

Commercial Procedure Codes

• 45378 – Colonoscopy, flexible; diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure)
• 45330 – Sigmoidoscopy, flexible; diagnostic, including collection of specimen(s) by brushing or washing, when performed (separate procedure)

If a polyp or other pathology is found and treated, this is considered a screening-turned-diagnostic procedure and the appropriate CPT code should be used based on the technique(s) with a modifier PT (colorectal cancer screening test; converted to diagnostic test or other procedure) added for Medicare or 33 (preventative services) added for commercial. If multiple methods of removal are used for separate polyps/lesions, then each method can be reported separately. For example, if a sigmoid polyp is removed using hot biopsy forceps and a rectal polyp removed via snare, 45384 and 45385 would be reported. Each technique is only reported once per encounter, even if multiple polyps/lesions were removed using that technique.

Common Diagnostic/Therapeutic Procedure Codes

• 45380 – Colonoscopy, flexible; with biopsy, single or multiple
• 45381 – Colonoscopy, flexible; with directed submucosal injection(s), any substance
• 45382 – Colonoscopy, flexible; with control of bleeding, any method
• 45384 – Colonoscopy, flexible; with removal of tumor(s), polyp(s), or other lesion(s) by hot biopsy forceps
• 45385 – Colonoscopy, flexible; with removal of tumor(s), polyp(s), or other lesion(s) by snare technique
• 45388 – Colonoscopy, flexible; with ablation of tumor(s), polyp(s), or other lesion(s) (includes pre- and post-dilation and guide wire passage, when performed)
• 45390 – Colonoscopy, flexible; with endoscopic mucosal resection

Diagnostic

When a patient presents for a colonoscopy due to a gastrointestinal issue, then this becomes a diagnostic procedure. Even if the patient qualifies for a screening, a screening cannot be coded if they have symptoms. The coder should code the symptoms or applicable findings and any interventions performed.

Positive Cologuard

Cologuard tests are commonly used as part of the colorectal cancer screening process as a less-invasive alternative to a colonoscopy. These tests detect alterations in a patient’s DNA associated with colon cancer and precancerous polyps. If a patient has a positive Cologuard test, a colonoscopy is necessary as a next step to survey for these lesions. According to the American Hospital Association¹, the subsequent test(s) following a positive Cologuard test are considered diagnostic, not screening.

When a patient undergoes colonoscopy for a positive Cologuard test and there are no abnormal findings, the coder would report the diagnosis as R19.5 (other fecal abnormalities). Per the official ICD-10-CM guidelines, “For patients receiving diagnostic services only during an encounter/visit, sequence first the diagnosis, condition, problem or other reason for encounter/visit shown in the medical record to be chiefly responsible for the outpatient services provided during the encounter/visit.”²

If the patient undergoes a colonoscopy for a positive Cologuard and a polyp is found, the coder would select K63.5 (polyp of colon) as the first-listed diagnosis for the colonoscopy. The guidelines for outpatient services state, “For outpatient encounters for diagnostic tests that have been interpreted by a physician, and the final report is available at the time of coding, code any confirmed or definitive diagnosis(es) documented in the interpretation.”

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References:

1. AHA Coding Clinic for HCPCS, Second Quarter 2018, Volume 18, Number 2, Page 4
2. AHA Coding Clinic for ICD, First Quarter 2019, Volume 6, Number 1, Page 32