Refinement of reference limits for alanine aminotransferase in the Korean elderly population

For the geriatric population, upper reference limits (URLs) for alanine aminotransferase (ALT) levels have not been established. The aim of the study was to determine the URLs for ALT and to describe the factors associated with elevated ALT level in an elderly population.

We set the URLs for ALT for participants aged 65 years and over (n=3646) based on the 2007-2009 Korea National Health and Nutrition Examination Survey at the 97.5th percentile of that population who were determined to be at low risk for liver disease (n=896; low risk was defined as testing negative for the HBs antigen, low alcohol intake, and the absence of metabolic syndrome, medical comorbidity, or medication use).

The URLs for ALT were 39 IU/L for men and 30 IU/L for women. The weighted prevalence for the elevated ALT level was 8.0% (95% confidence interval [CI], 7.1% to 8.9%) in the sample, 5.8% (95% CI, 4.7% to 7.1%) in men and 9.5% (95% CI, 8.3% to 10.8%) in women.

The URLs for ALT are established for the first time in the elderly, and our results may be useful for monitoring trends in the burden of liver disease, in addition to guiding the evaluation of ALT abnormalities in clinical practice.