Modified sperm stress test: a simple assay that predicts sperm-related abnormal in-vitro fertilization

Loss of sperm motility is associated with the process of sperm senescenceand occurs at different rates within a given normal or abnormal spermpopulation. Reactive oxygen species attack cell membrane phospholipids,generating fatty acid peroxides and other degradation products, that alsohave deleterious effects on sperm motility and fertilizing ability. Theobjective of this investigation was to study a modification of the originalsperm stress test (MOST), changing the culture medium to one offeringtransitional metals and shortening the total test time, to ascertainwhether it can predict fertilization under these laboratory conditions. Atotal of 41 semen samples was obtained from patients undergoing in-vitrofertilization (IVF) at our institution. Semen samples were grouped intothose producing total fertilization rates (FR) within normal limits(>50%) and those showing low total FR (<50%). The normal FR group hada significantly greater MOST mean value than the low FR group (0.71 versus0.44). Furthermore, there was a statistically significant correlationbetween the MOST score and ungrouped fertilization rates (r = 0.53, P =0.0004). Diagnostic statistics for MOST ratio values predicting <50% FRshowed an optimal threshold of 0.39. Collectively, sensitivity,specificity, positive predictive value and negative predictive value havetheir largest values at this threshold. Taking into account the abovementioned threshold figures, there is a significant association betweenMOST and FR categories (P = 0.0009). In conclusion, MOST is a simple assaythat has significant predictive value for sperm related IVF abnormalities.