Reactive oxygen species in human semen: validation and qualification of a chemiluminescence assay

Objective: To standardize and validate an assay for reactive oxygen species (ROS) in human semen.

Design: ROS levels assayed in blanks, negative and positive control samples (30% H2O2), and human semen, with the use of a luminol-based chemiluminescence assay measured in a single tube luminometer.

Setting: Andrology laboratory.

Patient(s): Semen samples from 19 men attending for routine semen analysis.

Intervention(s): None.

Main outcome measure(s): ROS levels reported in relative light units (RLU) per second, adjusted for sperm concentration.

Result(s): The ROS assay equipment performed according to expectations, generating a chemiluminescence signal for positive control samples and semen samples that decayed rapidly and was captured within 10 minutes. Blanks and negative control samples gave negligible readings. There was no significant intra- or interassay variation. Interference from extraneous factors was negligible. The assay distinguished changes in ROS over a wide range of concentrations and provided consistent results between reagent batches. Working reagents remained stable for 3 months. Acceptable levels for negative and positive control samples were established to set criteria for the test passing or failing on any given day. The assay was sensitive to ambient temperature >25°C. ROS declined significantly with time after ejaculation. Mechanical agitation doubled ROS production in semen.

Conclusion(s): These results validate the ROS assay and demonstrate that it is a highly reliable and accurate diagnostic test.