The New York City Medical Examiner's Office is reviewing more than 800 rape cases where DNA may have been mishandled by a lab technician.

It was prompted by the discovery of 26 cases where the technician failed to detect evidence where some existed.

A spokeswoman for the medical examiner says they discovered the errors through their own in-house quality control office and immediately reported the findings to the state's DNA committee.

She says they have since improved their quality control standards, and the technician involved no longer works for them.

The director of forensic biology at the office says all the errors were in reporting false negatives, meaning nobody was wrongfully convicted.