Delay in the application of the cover glass is a potential source of error with the Makler Counting Chamber

Abstract

Objective: To determine the effect of delaying the application of the cover glass of a Makler Counting Chamber (Sefi Medical Instruments, Haifa, Israel) on the apparent concentration of sperm or Dynabeads (Dynal Pty Ltd, Carlton, Victoria, Australia).

Design: Systematic alteration of the time taken to apply the cover glass.

Setting: Comprehensive infertility service.

Patient(s): Fresh semen from a patient or washed sperm from a donor.

Intervention(s): For the Makler Counting Chamber, a 5-microL drop of the sperm or bead suspension was placed in the center of the lower platform and the cover glass was applied either immediately (0 seconds) or after a delay of 5, 10, or 30 seconds.

Main outcome measure(s): The concentration of beads or sperm counted using an Improved Neubauer Hemocytometer or a Makler Counting Chamber.

Result(s): There was a progressive increase in sperm concentration with a longer delay in applying the cover glass when sperm was suspended in either seminal plasma or culture medium. Repeating the experiments with Dynabeads resuspended in phosphate-buffered saline, serum, or seminal plasma showed the same trend, although the suspension of beads in serum seemed to settle the least over the first 10 seconds.

Conclusion(s): Delay in the application of the cover glass is a potential source of error with the Makler Counting Chamber and should be avoided.