The assessment of oxidative stress in human semen: chaos and confusion in pursuit of diagnostic precision.

The importance of oxidative stress in the aetiology of male infertility has occasioned numerous clinical trials designed to assess the potential of antioxidants for treating this condition. These trials have not returned definitive results, probably because they have never selected participants on the basis of oxidative stress. Clearly, if a moderate to severe state of oxidative stress does not exist in semen, antioxidants can hardly be expected to improve fertility. To resolve this issue, robust, user-friendly point-of-care assays need to be developed that will enable clinicians to quickly diagnose and monitor oxidative stress in patients' semen. Traditional assays of total antioxidant capacity do not fulfil this role, because they are time consuming, expensive and laboratory based. The introduction of an alternative electrochemical system (MiOXSYS®) was designed to address this problem. This assay records the static oxido-reductive potential of semen and then creates an index by dividing this measurement by the sperm concentration. The creation of such an index is flawed and undermines many of the data generated to date. This commentary explains the nature of this problem and emphasizes the continuing unmet need for effective diagnostic procedures capable of detecting seminal oxidative stress in the patient population.