Enlarged spectrum of seminological diagnoses using the resazurin colour reaction; A spectrophotometric application

Abstract

Two sets of investigations were carried out in the present study to establish whether, in semen samples processed for the resazurin reaction (RT), the colour change and its intensity were informative for both the quality and quantity of spermatozoe. First, the results of RT were read visually single samples from 42 consecutive men from infertile couples. In the second step, the results were additionally read using a spectrophotometer. Single semen from fertile couples were analysed in this step. Visual analysis, Which involved grading against an RT colour chart, revealed a significant positive correlation between the RT result and the quantity and quality of spermatozoe. Azoospermia was diagnosed by grade number 1(dark purple, colour), while the highest grades 8-11 (colours dark red to pink) represented a homogeneous group of patients with the highest quality of spermatozoa (>60% motility) and quantity (>60% x 106/ml ejaculate). Normal parameters of spermatozoa, according to WHO, appeared with a high predominance (89-100% of cases) in this group and were present in most of the samples. Thus, the grades 8-11 might represent semen samples with optimal fertility potential. Spectrophotometric analysis of RT revealed that visual characteristics corresponded closely to the values for optical density (OD) of the samples. The OD for normo-zoospermic samples ranged between 1.6 and 1.84. RT evaluation using a spectrophotometer may therefore provide a tool for obtaining a wider spectrum of seminological diagnoses that classic microscopic examination, especially for distinguishing men with probable optimal fertility potential.