Establishment of allowable total error for semen analysis based on the state of the art in China

To establish evidence-based analytical performance specifications (APS), specifically allowable total error (TE_a), for five fundamental semen analysis parameters (sperm concentration, progressive motility, total motility, morphology, and vitality) in China utilizing the state-of-the-art model, and to compare these specifications with existing international benchmarks.

We examined national external quality assessment (EQA) data from 2019 to 2025, encompassing 315 laboratories across 30 provinces in China. TE_a was calculated using the state-of-the-art model as half the 10th-90th percentile range of result deviations from assigned values. Given that the participant count was below 100 from 2019 to 2022, this study eventually utilized data from 2023 to 2025 for the calculation of TE_a. The pass rate of participating laboratories was evaluated against the established TE_a criteria.

The established TE_a values as follows: sperm concentration, 34.3 %; progressive motility, 26.9 % (for assigned value ≤40 %) and 13.5 % (>40 %); total motility, 26.3 % (≤50 %) and 10.5 % (>50 %); morphology, 67.7 %; vitality, 24.6 % (≤60 %) and 7.9 % (>60 %). The pass rates for all parameters in recent EQA cycles were approximately 80 %, supporting the practical achievability of the proposed specifications. Comparisons showed that the derived TE_a values are generally consistent with or more refined than previous state-of-the-art and biological variation-based standards.

This study provides the first large-scale, evidence-based TE_a for semen analysis in China. The stratified TE_a for motility and vitality based on clinical thresholds, improves diagnostic accuracy. The proposed specifications are practical, achievable, and clinically relevant, providing a consistent foundation for quality assurance in reproductive medicine laboratories.