title: 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).
  
  
  METHODS
  Systematic alteration of the time taken to apply the cover glass.
  
  
  METHODS
  Comprehensive infertility service.
  
  
  METHODS
  Fresh semen from a patient or washed sperm from a donor.
  
  
  METHODS
  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.
  
  
  METHODS
  The concentration of beads or sperm counted using an Improved Neubauer Hemocytometer or a Makler Counting Chamber.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Delay in the application of the cover glass is a potential source of error with the Makler Counting Chamber and should be avoided.
authors.affiliation: Concept Fertility Centre, King Edward Memorial Hospital, Subiaco, Western Australia, Australia. concept@conceptfert.com.au
authors.forename: P
authors.initials: P
authors.lastname: Matson
authors.forename: J
authors.initials: J
authors.lastname: Irving
authors.forename: E
authors.initials: E
authors.lastname: Zuvela
authors.forename: R
authors.initials: R
authors.lastname: Hughes
mesh_terms: D005260:Female; D005898:Glass; D006801:Humans; D008297:Male; D008863:Microspheres; D012680:Sensitivity and Specificity; D013076:Sperm Count / Q000295:instrumentation*; D013997:Time Factors