Objective: To undertake a multi-centre study to maximize the number of Makler chambers used. Methods: A total of 15 laboratories participated with 31 Makler chambers. A suspension of latex beads was prepared to a concentration of 20 millions per milliliter, and 0.5 mL aliquots distributed to each participating laboratory. They measured the concentration on their Makler chamber(s) used for routine semen analysis by adding 3, 4, 5, 7 and 10 μL volumes of bead suspension to the chamber. Results: There was no difference in within-chamber analysis of the bead concentration according to the volume of bead suspension applied within the range of 3-10 μL (F4,14=2.634, P=0.056). However, the between-chamber effects were significantly different (F30,124=4.937, P=0.000), and 24/31 (77.5%) chambers tested had an average bias>10% compared to the target bead concentration. Conclusions: A volume of 3-10 μL added to Makler counting chambers does not influence the concentration measured of latex beads, but the between-chamber variability and positive bias seen would suggest that other sources of error are present which are yet to be identified.
- Makler chamber