Scoring human sperm morphology using Testsimplets and Diff-Quik slides

OBJECTIVE: To compare two staining methods to assess sperm morphology: Diff-Quik (DQ), which is the fastest of the recommended techniques, and Testsimplets (TS), a technique that uses prestained slides and is quite popular in in vitro fertilization (IVF) centers. DESIGN: Prospective study. SETTING: Patients at the Sterility Center of the Obstetrics and Gynecology Unit of the Hospital of S.S. Cosma and Damiano (Azienda USL 3 of Pistoia, Italy). PATIENT(S): 104 randomly enrolled male patients evaluated by the seminology laboratory. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Statistical comparison of sperm morphology results obtained after staining of semen samples both with DQ and TS. RESULT(S): Our data show that TS gives a statistically significantly lower number of normal forms than DQ (median: 6% [range: 0-29%] vs. 12% [range: 0-40%], respectively) as well as an overestimation of sperm head defects (median: 92.0% [range: 67%-100%] vs. 82.3% [range: 55%-100%], respectively). CONCLUSION(S): The two staining methods should not be considered equivalent. Specifically, the lower reference limit established by the World Health Organization is not appropriate when sperm morphology is assessed by TS. The routine application of TS in the evaluation of sperm morphology is therefore not recommended because it leads to an overestimation of patients with sperm morphology values below the lower reference limit (4%), thus potentially influencing clinical decisions.