Lynne Spalding, 57, was admitted to San Francisco General Hospital for treatment on September 19 and underwent treatment for infection.
Two days later, on September 21, Lynne Spalding disappeared.
San Francisco authorities and Spalding's family are seeking information on her whereabouts and appealing to the public for help in locating her.
"Lynne is an upbeat, lively person and her family's at a complete loss over her disappearance," family spokesperson David Perry said, in an interview with People.
Spalding, who had recently lost a great deal of weight, was being treated for an infection. Her condition was improving and listed as "fair" though family noted she seemed "very confused" when they last saw her.
Little information exists about Spalding's departure from the hospital and security footage cannot confirm that Spalding actually left the hospital.
They are conducting an internal investigation and cooperating with the San Francisco Police Department in hopes of finding Ms. Spalding.
She was last seen at approximately 10:15 on September 21 when a nurse stopped by to check on her. When the nurse returned 15 minutes later, Spalding was gone.
She left behind her cell phone and credit cards and is believed to have taken about $20.
Lynne Spalding is 5'6" and 105 pounds. She has long, dark hair and speaks with a heavy British accent. She is believed to be wearing dark jeans and a black sweatshirt.
Anyone with information on her whereabouts should call San Francisco Police Dispatch at (415) 553 0123 and reference case No. 130796086.