An update on the laboratory assessment of male fertility.

Contemporary methods of assisted reproduction have undoubtedly enhanced the opportunities for conception in couples suffering from male infertility. The causes of male infertility are multiple, and current therapies do not usually address an aetiological or pathophysiological origin. Consequently, there is a fundamental need to gain knowledge for optimization of the clinical management of male infertility. The correct identification of specific sperm deficiencies is the only rational approach to develop pathophysiologically oriented therapies. Therefore, we strongly advocate a thorough andrological evaluation in all cases with the emphasis on the assessment of sperm quality and quantity. Although no single sperm feature can accurately predict fertilization or pregnancy potential (which is related to the complexity of the sperm capacitation-fertilization-embryo development processes), the examination of multiple sperm characteristics allows the clinician to direct the patient to different therapeutic interventions. This laboratory evaluation should be approached using a sequential, multi-step analysis that includes the basic semen evaluation and, where appropriate, a more advanced assessment of sperm functions, including biochemical tests and bioassays predictive of fertilization outcome. The standardization of the most relevant clinical diagnostic tests should be a major goal of all those involved in the care of the infertile couple.