Pathology/Lab Coding Alert

Question: Our lab performs a full gene sequence analysis for MLH1 and finds mutations positive for Lynch syndrome. How should we code the case?

Texas Subscriber

Answer: The correct procedure code is 81292 (MLH1 [mutL homolog 1, colon cancer, nonpolyposis type 2] [e.g., hereditary non-polyposis colorectal cancer, Lynch syndrome] gene analysis; full sequence analysis).

Regarding the diagnosis, you should report the genetic test findings with a code such as Z15.09 (Genetic susceptibility to other malignant neoplasm).

Avoid: Don’t report Z84.81 (Family history of carrier of genetic disease) to report genetic test results that confirm an abnormal gene. You might report Z84.81 as the reason for the test if the patient undergoes the 81292 test based on a relative who is confirmed to carry the genetic mutation you’re testing for. Then you should also report the test findings.

Sequence: If the patient has a current malignant neoplasm, you’ll need to code that first, using the appropriate code, such as C18.- (Malignant neoplasm of colon…).

Similarly, if the patient had a past cancer diagnosis that is no longer current, you should use an additional code such as Z85.- (Personal history of malignant neoplasm…).

Lynch Syndrome, also called hereditary nonpolyposis colorectal cancer (HNPCC), is an inherited condition that increases a patient’s chance of getting cancer of the digestive tract, particularly the colon and rectum. People with Lynch syndrome also have an increased risk of cancers of the stomach, small intestine, liver, gallbladder ducts, upper urinary tract, brain, skin, and prostate.