A silver color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a red cross superimposed by a silver demi-sun at bottom and overall a green serpent entwined on a silver staff all between a maroon scroll at top inscribed "UT" and a maroon scroll at bottom inscribed "SANEMUS SERVIMUS" in silver letters.
Maroon and white/silver are colors traditionally associated with the Army Medical Corps. Green denotes vitality and good health. The red cross denotes medicine and healing. The staff and serpent are adapted from the staff of Aesculapius, the mythological God of Medicine, representing life-giving powers. The demi-sun adapted from the state crest, refers to California, the unit's home location. The motto translates to "We Serve To Heal."
The distinctive unit insignia was originally approved for the 921st Surgical Hospital on 2 October 1989. It was redesignated for the 921st Field Hospital effective 17 September 1993.