Labcorp (LH) said Thursday that it expanded its DPYD Genotyping test to help identify cancer patients at higher risk of severe side effects from fluoropyrimidine chemotherapy, including 5-fluorouracil and capecitabine.

The company said the updated test now covers all DPYD Tier 1 and Tier 2 genetic variants recommended by the Association for Molecular Pathology.

According to Labcorp, about 9% of patients carry DPYD variants that impair the body's ability to metabolize fluoropyrimidines, increasing the risk of toxic reactions such as neutropenia, diarrhea, and neurotoxicity. The company cited estimates linking 5-FU toxicity to roughly 1,300 deaths annually in the United States.