Semen has a gel-like consistency immediately following ejaculation. Liquefaction, or resolution of the gel-like consistency, is expected within 15 minutes at room temperature. If liquefaction does not occur within 60 minutes you should note this on the report sheet. Normal liquefied semen may contain gelatinous granules that do not liquefy. These are not significant and will not interfere with the semen analysis. However, mucus strands may interfere with the analysis.
WHO 5th edition recommends continuous gentle mixing or rotation of the sample container on a surface rotator, either at room temperature or in a 37°C incubator during liquefaction to help produce a homogeneous sample.
If liquifaction does not occur within 60 minutes, the specimen can be treated to aid in laboratory testing. Liquefaction and homogenizing of samples that do not normally liquefy may be accomplished using one of the following methods
- Mechanical mixing -- repeated gentle passage through an 18/19 gauge blunt needle attached to a syringe.
- Addition of equal volumes of a physiological medium (eg, saline) and repeated pipetting of the sample.
- Enzymatic digestion by bromelain, or chymotrypsin (proteolytic enzymes).
Semen samples should never be vortexed to aid in liquefaction. Vortexing will damage the sperm.
Samples that do not liquefy within 60 minutes should be recorded as having abnormal liquefaction as the accuracy of some results will be affected. For example, addition of enzymatic or physiological agents may affect semen biochemistry, sperm concentration, sperm motility, and morphology.