Objective: To provide a simple, universally applicable method of quality assurance for sperm counting, thereby reducing intercounting chamber variation.
Design: By using a known concentration of latex beads, the sperm:bead ratio can be used to calculate the actual sperm count.
Main outcome measures: The mean sperm and bead counts were determined in both a Spot-lite hemocytometer (Baxter Diagnostics, McGaw Park, IL) and a Makler chamber (Polymedco Inc., Yorktown, NY) from 21 different ejaculates mixed with a known concentration of beads. The hemocytometer chamber was used as the standard counting chamber because it consistently yielded a low variation in sperm count. The adjusted sperm concentration of the Makler chamber was calculated using the following formula [hemocytometer beads]/[Makler beads] x [Makler sperm].
Results: Observed mean +/- SD sperm counts were significantly different between the hemocytometer chamber (110.6 +/- 66.2 x 10(6)/mL) and Makler chamber (173.3 +/- 103.5 x 10(6)/mL). However, calculated Makler chamber sperm counts (118.1 +/- 76.1 x 10(6)/mL) was not statistically different from observed hemocytometer sperm counts.
Conclusion: This novel approach to sperm counting using a known concentration of latex beads as a reference material can be used to reduce variation in sperm counting between observers, counting chambers, and possibly computerized sperm analyzers.