Risk factors for mismatches in the ART laboratory: an analysis of 73,719 electronic witnessing points

What are the risk factors for mismatches (involving or not involving biological material) and critical mismatches (CMM; involving biological material) in an assisted reproductive technology laboratory equipped with an electronic witnessing system (EWS)?

In total, 73,719 witnessing points were extracted retrospectively from an EWS database, representing 11,210 consecutive treatment cycles performed at Fertility North between January 2016 and July 2023.

Overall, 138 (0.19%) mismatches and 16 (0.02%) CMM were identified during the study period. Significant differences were detected in both mismatch (P = 0.003) and CMM (P = 0.038) rates between different time periods of the day. The mismatch rate was highest between 12 pm and 2 pm (0.28%), whilst the CMM rate was highest after 4 pm (0.13%). Neither mismatches nor CMM were associated with a specific weekday or weekend day/public holiday (P = 0.886 and 0.183, respectively). Both mismatch (P < 0.001) and CMM (P < 0.001) rates differed significantly between eight laboratory processes. The mismatch rate was highest during embryo transfer (0.36%), and the CMM rate was highest during oocyte denudation (0.13%). Furthermore, the mismatch rate differed significantly between 20 operators (P < 0.001), whereas the CMM rate did not (P = 0.216). Multivariate logistic regression found that six laboratory processes [in the order from higher to lower risk, oocyte denudation (P < 0.001), embryo transfer (P < 0.001), cryopreservation (P = 0.002), sperm preparation (P = 0.003), oocyte collection (P = 0.007) and insemination (P = 0.006)] and four individual operators (P = 0.005, 0.037, 0.010 and 0.048, respectively) were associated with mismatches. On univariate regression analysis, time after 4 pm (P = 0.020) and oocyte denudation (P < 0.001) were the only risk factors associated with CMM.

Mismatches are associated with specific laboratory processes and individual operators, while CMM are associated with time after 4 pm and oocyte denudation.