The performance of 10 different methods for the estimation of sperm concentration.

OBJECTIVE To evaluate the performance of different methods of sperm counting using latex beads and sperm suspension. DESIGN A quality-control study. SETTING University-based andrology laboratory. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Counting latex beads six times in two standard suspensions using 10 methods and counting spermatozoa with 4 methods. RESULT(S) When air-displacement pipettes were used, the disposable chambers Standard Count (Leja, Amsterdam, Holland), Cellvision (Anthos-ec, Heerhugowaard, The Netherlands), and Cell Vu (Fertility Technologies, Inc. Natick, MA) showed small variation and correct estimation of bead concentration. All the reusable chambers gave relatively large variability, with tendency to underestimate (improved Neubauer; Hawksley, Lancing, United Kingdom) or to overestimate the bead concentration. The use of plunger-displacement pipettes resulted in an overestimation of bead concentration in medium but not in seminal plasma. Counting the sperm suspension using plunger-displacement pipettes indicated that the Bürker hemocytometer overestimated concentration relative to that obtained by Cellvision and Makler Counting Chambers (Sefi Medical Instruments, Haifa, Israel) and that the improved Neubauer presented the lowest variability (7.1%). CONCLUSION(S) The improved Neubauer hemocytometer is the standard for sperm counting, though disposable chambers give reliable results as well. If beads are used to evaluate the accuracy of counting chambers, it is recommended to dilute them with seminal plasma.