Age- and sex-specific reference intervals for ALT with 95% CIs among sub-Saharan adults

Introduction Liver diseases, especially chronic hepatitis B and C, are common and are associated with a high mortality rate in Africa. Elevated serum Alanine Aminotransferase (ALT) levels are the most specific biomarker of hepatocyte necrosis. However, reference intervals (RIs) for ALT remain undetermined in Cameroon. This study aimed to establish 95% CI reference intervals for serum ALT among Cameroonian adults. Methods From November 2019 to June 2020, we conducted a cross-sectional study of 274 healthy volunteers aged 18-65 years. The assays were performed on a Cobas 6000®. We used the percentile method with 95% CI to assess the RI and examined the influence of age, sex, place of residence, food cultural habits, and education level on ALT levels owing multivariate analysis via Stata 15. The Results Among the 274 participants, the mean age was 31.68 years, and the sex ratio was 0.68. The median ALT levels was 13.5 [IQR, 9.9-18.7] IU/L. These levels were influenced by age ( P = 0.003) and sex ( P < 0.0001). The reference intervals were 6.4 [95% CI, 4.9-7.4] to 39.1 (33.8-58.2) IU/L overall, 7.4 [95% CI, 5.6-8.3] to 39.1 [95% CI, 34.1-46.1] IU/L for men, and 5.9 [95% CI, 1.2-7.3] to 28.9 [95% CI, 27.4-36.1] IU/L for women. In terms of age group, the reference intervals were 5.9 [95% CI, 2.7-7.3] to 33.8 [95% CI, 29.8-42.8] IU/L for those under 35 years and 6.9 [95% CI, 6.1-8.6] to 36.2 [95% CI, 32.4-39.0] IU/L for those 35 years and older. Conclusion This study pioneered the establishment of ALT reference intervals with 95% CIs in Africa and the exploration of RIs based on age group among 18-65 years people.