Pathology/Lab Coding Alert

Focus on cytogenetic test results.

Just one code (758.0, Down’s syndrome) won’t cut it anymore to report Down’s syndrome once you’re no longer using ICD-9.

Instead, you’ll need to select one of several ICD-10 codes for the condition beginning Oct. 1, 2015.

Focus on Trisomy 21

Labs may perform chromosome analysis studies that identify various forms of Trisomy 21, often called Down syndrome, which involves abnormal cell division resulting in extra genetic material from chromosome 21.

The three primary types of Trisomy 21 account for the four ICD-10 codes that you’ll have to report the diagnosis based on chromosome analysis or other test results. The codes are as follows:

• Q90.0 — Trisomy 21, nonmosaicism (meiotic nondisjunction)
  

This accounts for the vast majority of Down syndrome cases, when the individual has three copies of chromosome 21 instead of the usual two copies.

• Q90.1 — Trisomy 21, mosaicism (mitotic nondisjunction)
  

When the individual has some cells with normal chromosome 21 and some with extra chromosome 21 material, the condition is called mosaic Down syndrome.

• Q90.2 — Trisomy 21, translocation
  

If a portion of chromosome 21 attaches (translocates) to another chromosome, the additional genetic material results in the translocation form of Down syndrome

• Q90.9 — Down syndrome, unspecified
  

Use this code if the medical record doesn’t note the specific chromosomal abnormality behind the Down syndrome diagnosis.