Influence of three different preparation techniques on the results of human sperm morphology analysis.

Using 158 unselected semen samples the present study has analysed how the results of sperm morphology assessment were influenced by different techniques for preparing the slides for microscopic assessment. All three techniques compared, the Papanicolaou stain (PAP), the Shorr stain (SHO) and the 'wet preparations' protocol (WET) are currently recommended by the World Health Organization for use in andrology laboratories. Mean percentages of morphologically normal spermatozoa were identical on PAP and SHO slides (31.1%), but were significantly lower in wet preparations (12.3%). Wide divergence of results obtained with the three different methods was also found with respect to the percentage of sperm with head, midpiece and tail defects and two 'indices of teratozoospermia'. For the majority of parameters assessed, linear regression analysis revealed a poor correlation between evaluations of PAP, SHO and WET slides (r values ranging from 0.01 to 0.87). We conclude that only one standard method should be recommended for the preparation of morphology slides in order to ensure inter-laboratory comparability of results and to enhance the value of sperm morphology analysis for predicting fertility.