Objective: The study aim is to determine which type of material - pipette tips or culture medium - is more appropriate for use in a cytotoxicity external quality control programme (CT-EQC).
Study design: The results of the participating laboratories in Spanish CT-EQC programme for human reproduction laboratories during the period 2013-2016 were analyzed. Per year, laboratories receiving three pipette tips and three aliquots of culture medium. All laboratories used the human sperm survival test to perform the bioassay. On average 48 laboratories took part in the programme each year. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy were calculated, with the corresponding 95% confidence intervals.
Results: Overall, for both products, sensitivity was higher than specificity, and NPV was higher than PPV. For laboratories participating for the first time in the CT-EQC, lower results were obtained in sensitivity and specificity in culture media than in pipette tips. However, in subsequent years, these differences disappeared. The PPV obtained for pipette tips was higher than that obtained for culture media (0.82 (0.77-0.87) vs 0.71 (0.66-0.76)). No relationship was recorded between the laboratories' accuracy in culture media and pipette tips (r = 0.026).
Conclusions: From a logistical standpoint, pipette tips are more appropriate than culture medium for use in a CT-EQC programme.
Keywords: Andrology; Bioassay; External quality control; Human sperm survival test; Reprotoxicity.
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