Increased blood levels of alanine amino transferase (ALT, also known as SGPT; serum glutamic pyruvic transaminase) serve as a marker of liver injury by various mechanisms. Less is known about the clinical implications associated with low-normal ALT levels. Previous studies showed low ALT levels to be associated with poor long-term outcomes among elderlies, serving as a biomarker for increased incidence of frailty and subsequent risk of mortality. However, it has not been determined yet whether low-normal ALT values might be predictive of frailty and mortality in younger, middle-aged adults.
