Establishment of gender- and age-specific reference intervals for serum liver function tests among the elderly population in northeast China: a retrospective study

Introduction: Reference intervals (RIs) for younger population may not apply to the elderly population. The aim of this study was to establish gen- der-and age-specific RIs for serum liver function tests among the elderly population and to compare with younger population RIs currently used in China and other countries. Materials and methods: This was a retrospective study, and subjects (>= 18 year-old) were recruited from the laboratory information system (LIS) at the First Hospital of Jilin University between April 2020 and April 2021. The following parameters were collected: aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), alkaline phosphatase (ALP), total protein (TP), albumin (ALB), total bilirubin (TBIL), and direct bilirubin (DBIL). The Tukey method was used to eliminate outliers. Reference intervals were established by the nonparametric method. Results: A total of 23,597 healthy individuals were enrolled in the study. From all parameters AST, ALT, TP and ALB required no gender partition, while ALT, GGT, TP, ALB and DBIL required different partitions for age. Activities and concentrations of ALT, ALB, and TP showed a downward trend in the elderly aged 60-89. In contrast, DBIL showed a gradual upward trend. Conclusion: The RIs for liver function tests among healthy elderly population were different from those among young population in China. There were apparent gender and age differences in the RIs of liver function for elderly and significant differences compared with national standards and RIs in other countries. Therefore, it is necessary to establish gender-and age-specific RIs for serum liver function tests among the elderly population.