Shares of Genomic Health ( GHDX) jumped 15% after the company said insurer UnitedHealth ( UNH) will cover the use its Oncotype DX tests to detect the risk of recurrence in breast cancer patients.

The tests are used to measure the likelihood of breast cancer recurrence in patients who've already been diagnosed, and to predict the possible benefit a patient might have from chemotherapy, Genomic Health said.

The stock was gaining $3.19 to $23.87.