title: A technique for standardization and quality control of subjective sperm motility assessments in semen analysis.
abstract: OBJECTIVE
  To establish a quality control method to monitor and eventually to standardize the subjective assessment of sperm motility in conventional semen analysis.
  
  
  METHODS
  Quality control study running over 2 years.
  
  
  METHODS
  University infertility clinic and andrology laboratory.
  
  
  METHODS
  Randomly chosen patients attending the clinic.
  
  
  METHODS
  Conventional semen analysis with sperm motility assessed by grading according to the World Health Organization (WHO) criteria and analysis of individual sperm tracks with a computer-aided sperm analysis (CASA) system. Formulas were established to identify, from the track data, the threshold velocity values for distinguishing between motility grades a and b and motility grades b and c for each technician.
  
  
  RESULTS
  The subjective thresholds above which technicians categorized sperm as WHO grades a and b were determined by CASA to be 61 +/- 1 and 11 +/- 1 micron/s (straight-line velocity), respectively. Agreement among three to five technicians over 2 years was reasonable (coefficient of variation < 20%), but threshold values were variable.
  
  
  CONCLUSIONS
  Agreement within and between laboratories in the assessment of sperm motility grades could be achieved by agreeing on designated values for threshold velocities for grade a and b sperm. On the basis of such values, CASA analysis could be used to provide the expected percentages of grades a, b, and c forms for quality control samples recorded and distributed on videotapes, against which technicians could adjust their subjective assessments.
authors.affiliation: Institute of Reproductive Medicine, University of Münster, Germany.
authors.forename: C H
authors.initials: CH
authors.lastname: Yeung
authors.forename: T G
authors.initials: TG
authors.lastname: Cooper
authors.forename: E
authors.initials: E
authors.lastname: Nieschlag
mesh_terms: D000704:Analysis of Variance; D003936:Diagnosis, Computer-Assisted / Q000379:methods / Q000592:standards*; D006801:Humans; D007248:Infertility, Male / Q000175:diagnosis*; D008297:Male; D011786:Quality Control; D012661:Semen; D013081:Sperm Motility; D014944:World Health Organization