Abi Lerner was a medical officer aboard the S.S. Pentallian.
Abi conducted tests on Hal Korwin to see why he would not open his eyes and why he was unconscious. The Tenth Doctor liked Abi because she already had done what he was about to say. She was the first victim of Korwin, who was then possessed by the sentient star Torajii. (TV: 42)