Analysis of Cytogenetic Detection Findings in National Radiation Worker Medical Examinations: Cytogenetic Testing Should Be Standardized (A Multicenter Data Analysis)

Objective: To report cytogenetic test results from the 2025 national occupational health examinations of radiation workers in China and to examine variation in abnormality rates across institutions and regions. Methods: Data were obtained from 46 institutions for chromosomal aberration (CA) analysis, 40 for conventional lymphocyte micronucleus (MN) assays, and 6 for cytokinesis-block (CB) MN assays. Weighted abnormality rates were calculated using institution-level sample sizes as weights. The Shapiro-Wilk test assessed distribution normality. K-means clustering stratified institutions by sample size and detection rate. Regional effects were examined by comparing national data with and without Henan province. Results: The weighted abnormality rate was 4.40% for CA (100,684 tests), 1.28% for conventional MN (183,910 tests), and 0.18% for CB-MN (12,096 tests). Excluding Henan reduced the CA rate to 3.20%. All three indicators deviated from normality (all P < 0.001). K-means clustering identified three institutional groups: low-abnormality (n = 32, mean 1.85%), medium-abnormality large-sample (n = 8, mean 3.76%), and high-abnormality (n = 6, mean 12.32%; maximum 25.99%). No linear association was found between sample size and abnormality rate (r = 0.128, P > 0.05). Conclusion: Considerable inter-institutional and regional variation was observed in cytogenetic detection rates. CA detected abnormalities more frequently than MN assays. Institutions with high rates warrant review of radiation protection practices and testing quality. Standardized procedures and region-specific surveillance may improve data reliability.