The medical fellowship candidate nicknamed “Thirteen” in House M.D. was Remy Hadley.
Remy Hadley earned the nickname “Thirteen” after becoming the thirteenth candidate in House’s selection process for a new diagnostic team. The character’s private life and medical history gradually became important parts of the series, especially after she disclosed that she carried the gene for Huntington’s disease.
Olivia Wilde portrayed Hadley. Thirteen became one of House’s most recognizable fellows and eventually worked with the diagnostic department after the competition ended.
The nickname is often remembered more readily than the character’s real name, which is why the two are easy to mix up. Amber Volakis was another fellowship candidate, while Allison Cameron and Martha Masters were separate members of House’s broader medical circle.