Althea Davis is a nurse who has worked in several medical jobs that have brought her into contact with Sheldon, Leonard, Howard, and Bernadette.
In the "Pilot" episode, Althea worked as a receptionist at the High IQ Sperm Bank, where Sheldon and Leonard went to donate sperm in order to earn money for fractional T1 bandwidth. Althea was attempting to complete a crossword at her desk, but Leonard intervened and solved the puzzle for her.
In "The Peanut Reaction," Althea worked as a nurse in a hospital emergency room when Howard initially faked an allergic reaction to keep Leonard out of the apartment for a few hours. When Althea refused to play along with his plan, Howard ate a peanut granola bar and suffered an anaphylactic shock.
In "The Robotic Manipulation", Althea was also in the emergency room when Howard arrived with a robot hand stuck on an intimate part of his anatomy. Althea solved his problem by turning the computer off and on again, although Howard was apprehensive about this solution.
In "The Werewolf Transformation", Sheldon attempted to visit his barber in the hospital for a haircut. However, Althea caught him and mistook him for a patient who had escaped from the psych ward.
Althea was a nurse in the maternity ward when Bernadette arrived early in "The Birthday Synchronicity". As Bernadette was accompanied by Howard, Raj and Stuart, Althea wondered if Bernadette knew who the father was or whether this was some “Mamma Mia nonsense”.
- Althea's last name, Davis, was revealed on her name tag in "The Birthday Synchronicity".
- Vernee Watson also appeared as Althea Davis in the unaired pilot of The Big Bang Theory made for the 2006/07 season.