Pathology/Lab Coding Alert

Lab test method, purpose, drive code choice.

With a growing number of lab tests that physicians might order to assess a patient for colorectal cancer (CRC), we’ve had lots of questions from readers on this subject.

Study the following questions and answers to master your understanding of this complicated topic.

Understand Screening Criteria

Question 1: What distinguishes a screening CRC test from a diagnostic test?

Answer 1: The simple answer is that labs perform a screening test in the absence of signs or symptoms of disease, and all other tests are diagnostic.

The more complicated answer is that Medicare and many other payers outline patient eligibility for a screening CRC test for average risk/asymptomatic patients beginning at age 50 years, as follows:

• Screening fecal occult blood test (FOBT) or fecal immunochemical test (FIT) — Once every 12 months.
• Screening flexible sigmoidoscopy — Once every 48 months, or 120 months after a previous screening colonoscopy.
• Screening colonoscopy — Once every 120 months, or 48 months after a previous flexible sigmoidoscopy.
• Screening barium enema — Once every 48 months when used instead of sigmoidoscopy or colonoscopy.​
• Multi-target stool DNA test (like Cologuard^®) — Once every three years for people who meet all these conditions:

                    o Between 50 and 85 years of age.
                    o They show no signs or symptoms of colorectal disease including, but not limited to, lower gastrointestinal pain, blood in stool, positive guaiac fecal occult blood test, or fecal immunochemical test
                    o They’re at average risk for developing colorectal cancer, meaning they have no personal history of adenomatous polyps, colorectal cancer, or inflammatory bowel disease, including Crohn’s Disease and ulcerative colitis.
                    o They have no family history of colorectal cancers or adenomatous polyps, familial adenomatous polyposis, or hereditary nonpolyposis colorectal cancer.

Medicare also defines appropriate diagnosis coding for these average-risk screenings as Z12.11 (Encounter for screening for malignant neoplasm of colon) or Z12.12 (Encounter for screening for malignant neoplasm of rectum).

High risk: Screening for high-risk patients is different, according to Medicare, and is not subject to age restrictions. The following ICD-10 codes are some examples of diagnoses that meet the high-risk criteria for colorectal cancer:

• Z80.0 (Family history of malignant neoplasm of digestive organs)
• Z83.71 (Family history of colonic polyps)
• Z85.00 (Personal history of malignant neoplasm of unspecified digestive organ)
• Z85.810 (Personal history of malignant neoplasm of tongue).

Other than the preceding primary diagnoses, some secondary diagnoses from among the following family of diagnostic codes may also apply:

• K50. -- (Crohn’s disease (regional enteritis))
• K51. -- (Ulcerative colitis)
• K52. -- (Other and unspecified noninfective gastroenteritis and colitis).

The final determination of an appropriate diagnosis for being at high risk has been left with the local Medicare contractors, and the codes that each one will accept can vary significantly, says Glenn D. Littenberg, MD, MACP, FASGE, AGAF, a former CPT^® Editorial Panel member in Pasadena, California.

Distinguish Stool Tests

Question 2: How should we code a screening test for occult blood in a fecal specimen?

Answer 2: The tried and true FOBT has long been the bread and butter of laboratory testing to screen for colorectal cancer.

Tip: You might see this test ordered as a “guaiac” or “peroxidase activity” test, according to William Dettwyler, MT AMT, president of Codus Medicus, a laboratory coding consulting firm in Salem, Ore.

Procedure: The assay involves applying fecal smears on cards containing a substance originally extracted from a guaiacum tree, which will turn blue in the presence of a test reagent containing hydrogen peroxide only if blood is present in the stool.

Coding: CPT^® provides one code for this screening test: 82270 (Blood, occult, by peroxidase activity (e.g., guaiac), qualitative; feces, consecutive collected specimens with single determination, for colorectal neoplasm screening (i.e., patient was provided 3 cards or single triple card for consecutive collection)). Notice that the specimen is three consecutively-collected feces samples.

Diagnosis: Because this is a screening test, the appropriate diagnosis code would be Z12.11 (Encounter for screening for malignant neoplasm of colon) or Z12.12 (Encounter for screening for malignant neoplasm of rectum).

Caution: Don’t report the following related codes for the fecal screening test:

• 82271 (… other sources). Use this code for other-source specimens, such as vomit.
• 82272 (Blood, occult, by peroxidase activity (eg, guaiac), qualitative, feces, 1-3 simultaneous determinations, performed for other than colorectal neoplasm screening).

Although the lab test and specimen source are the same for codes 82270 and 82272, you should use 82272 only for a diagnostic test, says Melanie Witt, RN, CPC, MA, an independent coding expert based in Guadalupita, N.M.

That means you should reserve 82272 for fecal specimens taken when the patient has signs or symptoms, including a single fecal specimen taken during a digital rectal exam (DRE).

Immunoassay is different: Although all FOBTs used to be guaiac-based, newer tests identify occult blood in a fecal specimen using immunoassay techniques. You might see this test called Immunochemical FOBT, Immunoassay FOBT, iFOBT, or FIT (fecal immunochemical test).

The FIT procedure involves mixing a reagent containing antihuman hemoglobin antibody with a fecal specimen. The antibody joins with any hemoglobin in the fecal specimen, if present, creating a clumping, or agglutination reaction, which the lab analyst measures as an optical change in the test mixture.

Clinicians may prefer this test over FOBT, both for accuracy and to avoid possible complicating factors, such as meat consumption or rectal bleeding that can interfere with guaiac test results.

You have the following two codes to choose from for the FIT test:

• 82274 (Blood, occult, by fecal hemoglobin determi­nation by immunoassay, qualitative, feces, 1-3 simultaneous determinations)
• G0328 (Colorectal cancer screening; fecal occult blood test, immunoassay, 1-3 simultaneous).

Caution: For Medicare and many other payers, you should report G0328 for the screening test, and reserve 82274 for a diagnostic FIT test ordered based on signs or symptoms.

Read more about CRC lab tests, including details on Cologuard^®, in the following article.