Validation of sORP, a Measure of Oxidative Stress, in Australian Population

Abstract

Background: Excessive reactive oxygen species are normally eliminated by seminal plasma free radical antioxidant scavengers and enzymes. Assessing the oxidation reduction potential of seminal fluid (mV/million sperm/mL) enables the detection of an imbalance in this biological mechanism, and identifies patients exhibiting oxidative stress (OS). A novel technology, MiOX[Formula: see text], detects static Oxidation-Reduction Potential (sORP), providing a comprehensive measure of oxidants and reductants in semen, with the advantages of rapid, simple and less sample volume compared to the conventional chemiluminescence assay. Aim: This study aims to validate the MiOX[Formula: see text] analyser for the detection of OS in seminal fluid, in the Australian population. Method: Samples were collected from consenting patients attending the Royal Women’s Hospital Andrology Unit for semen analysis (n=144); those with [Formula: see text]1 million/ml were excluded. Semen analysis was carried out as per WHO 2010 guidelines, and replicate sORP measurements taken within 60 minutes of ejaculation. Results: Replicate sORP measurements from semen samples (n=20) demonstrated no significant differences between and within operators, and across days. sORP did not vary between samples incubated at 4[Formula: see text]C, room temperature, and 37[Formula: see text]C, or samples subjected to mechanical agitation. Freeze-thaw resulted in a significant increase in sORP (p=0.031). The stability of sORP measurements was demonstrated up to 4 hours after ejaculation, however, significant increases were observed after 24 and 48 hours (p[Formula: see text]0.05). Patients grouped according to normal and abnormal total motile sperm count (TMSC) demonstrated significantly different sORP (0.75 ± 0.86, 5.02 ± 5.32, p[Formula: see text]0.001). A preliminary ROC analysis, using TMSC, revealed a cut-off value of 1.07 mV/106 sperm/mL (AUC=0.904) with 81.1% sensitivity and 81.3% specificity. Conclusion: Results from the technical validation are consistent with other studies. The clinical reference range validation requires further patient samples to better reflect the distribution of results observed in the low TMSC group.