Diagnosis Coding When Presenting for Colonoscopy-Screening

Primary Diagnosis for Colonoscopy Records

Coding colonoscopy records has always been a challenge when it comes to reporting the primary diagnosis for the account. All colonoscopy procedures are performed to look for potential malignancy and some coders think that all of these should be coded as screenings, code Z12.11. The coding advice for reporting screening vs. follow-up did not change with the implementation of ICD-10-CM.

Screening Colonoscopy

If the patient presents for a screening colonoscopy and a polyp or any other lesion/diagnosis is found, the primary diagnosis is still going to be Z12.11, Encounter for screening for malignant neoplasm of colon. The coder should also report the polyp or findings as additional diagnosis codes. When a screening colonoscopy is performed, the screening code would be reported regardless of the findings during the exam or other procedures performed due to the findings.

Surveillance Colonoscopy

Surveillance is often used to describe the visit for the colonoscopy. If a patient has had previous removal of colon polyps a few years ago and is now presenting for surveillance colonoscopy to look for any additional polyps or recurrence of the polyp this is coded with Z12.11, Encounter for screening for malignant neoplasm of colon as the first listed code. Surveillance colonoscopies are still screenings. However, the coder must be cautious as sometimes the physician will document “surveillance” colonoscopy when in fact what he is performing is a follow-up colonoscopy. Read and be guided by all the information within the medical record.

Follow-up Examination

Follow-up examination is typically performed when a patient has been found on previous exam to have a potentially malignant neoplasm or lesion that is suspicious for malignant transformation. A patient that had colonoscopy a few months ago with polypectomy, for adenomatous polyp, returns for follow-up examination to look for recurrence would be coded as a follow-up examination with Z09, Encounter for follow-up examination after completed treatment for conditions other than malignant neoplasm. If the follow-up is being performed after removal of malignancy, then Z08, Encounter for follow-up examination after completed treatment for malignant neoplasm would be reported as the first listed code.

Outpatient Colonoscopy

When a patient presents for outpatient colonoscopy due to symptoms that they are having, then the symptom or finding would be the primary diagnosis. If a cause is found/identified by the physician to be the culprit of the symptoms, then this would be the primary diagnosis. If the patient presents with changes in bowel habits and during the colonoscopy the patient is found to have severe sigmoid diverticulosis, the primary diagnosis would be the symptom unless the physician specifies that the symptom is due to the finding of diverticulosis. If the physician does state that the diverticulosis is the postoperative diagnosis or the etiology of the symptoms, then the diverticulosis is the primary diagnosis.

As always, be sure to reference any facility specific coding guidelines to determine if there is any specific guidance to follow.


AHA Coding Clinic® for ICD-10-CM and ICD-10-PCS, First Quarter 2018 Pages: 6-7
AHA Coding Clinic® for ICD-10-CM and ICD-10-PCS, First Quarter 2017 Pages: 8-9, 14
AHA Coding Clinic® for ICD-10-CM and ICD-10-PCS, Fourth Quarter 2015 Pages: 8-9
AHA Coding Clinic® for ICD-9-CM, Fourth Quarter 2013 Page: 105
AHA Coding Clinic® for ICD-9-CM, First Quarter 1995 Page 4
AHA Coding Clinic® for ICD-9-CM, Third Quarter 1992 Page: 11
AHA Coding Clinic® ICD-9-CM, May-June 1984 Page 10
AHA Coding Clinic® for ICD-9-CM, July-August 1985 Page: 16
AHA Coding Clinic® for ICD-9-CM, Second Quarter 1995 Page: 8
Official Guidelines for Coding and Reporting FY 2017, Pages: 104-108
AHA Coding Clinic for ICD-10-CM/PCS, First Quarter 2018 Page: 6-7

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The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.

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