In this section
Reports show reference values from the WHO guidelines (2021).
Lower reference limits (5th centiles and their 95% confidence intervals) for semen characteristics :
| Parameter | Lower reference limit |
| Semen volume (ml) | 1.4 (1.3-1.5) |
| Total sperm number (106 per ejaculate) | 39 (35-40) |
| Sperm concentration (106 per ml) | 16 (15-18) |
| Progressive motility (PR, %) | 30 (29-31) |
| Sperm morphology (normal forms, %) | 4 (3.9-4.0) |
| Vitality (live spermatozoa, %) | 54 (50-56) |
| pH | ≥ 7.2 |
Measurement uncertainty values for semen analysis
Every measurement is subject to some uncertainty. Measurement uncertainty can come from the measuring instrument, from the item being measured, from the environment, from the operator, and from other sources. Measurement uncertainties can be estimated using statistical analysis of a set of measurements. The use of good practice such as traceable calibration, careful calculation, good record keeping, and checking can reduce measurement uncertainties.
In order to provide a measure of confidence in results produced by a laboratory, it is necessary to identify all factors which may contribute to variation of measurement in a process and assess the potential to influence uncertainty. Once identified these factors must be reduced or controlled to an acceptable level and a value for the range of acceptable uncertainty assigned where possible.
Andrology has determined the measurement uncertainty values for semen analysis. They are reviewed regularly and reassessed whenever a significant change in the procedure occurs, e.g. new equipment or modification of the assay. These uncertainty measurement values are available upon request.