Abstract: Objective To investigate the changes of peripheral blood T lymphocyte subsets in healthy adults in Qijiang area, and to establish the laboratory reference range of T lymphocyte subsets in Qijiang area. Methods From April 1, 2022 to April 10, 2023, 311 cases of physical examination in various hospitals in Qijiang area were selected as the subjects of this study. The average age was ( 32.35 ± 5.83 ) years old. Venous blood was collected from healthy subjects with empty stomach in the morning, and T lymphocyte subsets in peripheral blood of 311 healthy adults were detected by flow cytometry. Results The absolute count of total lymphocytes, total T lymphocytes, percentage of CD8⁺ lymphocytes and absolute count of CD8⁺ lymphocytes in males was higher than that of females, and the percentage of CD4⁺ lymphocytes was lower than that of females, and the difference was statistically significant (P<0.05), while there was no significant difference in the percentage of total T lymphocytes, absolute count of CD4⁺ lymphocytes and CD4⁺/CD8⁺ between the two groups (P>0.05). There was no significant difference in the indexes of different age groups (P>0.05). The peripheral blood T lymphocyte subsets of 311 healthy subjects were analyzed by percentile method, and the 95% confidence interval of each index was used as the reference range of healthy adults in Qijiang area. The results were as follows: total lymphocyte absolute count 1 520×10⁶/L~3 780×10⁶/ L, total T lymphocyte absolute count 950 ×10⁶/L~2 840×10⁶/L, total T lymphocyte percentage 49%~85%, CD4⁺ lymphocyte absolute count 545×10⁶/L~1 420×10⁶/L, CD4⁺ lymphocyte percentage 26%~50%, CD8⁺ lymphocyte absolute count 318×10⁶/L~1 255×10⁶/ L, CD8⁺ lymphocyte percentage 12%~42%, CD4⁺/CD8⁺ ratio 0.70~2.90. Conclusion Gender will affect some indicators of peripheral blood T lymphocyte subsets in healthy adults. It is of great significance to establish a reference range of peripheral blood T lymphocyte subsets suitable for healthy adults in the region for the diagnosis of diseases.

Key words: T lymphocyte subsets, healthy adults, flow cytometry, reference range, Qijiang area