A comparison of methods used in the UK and Ireland for the extraction and detection of semen on swabs and cloth samples

The recent formation of a United Kingdom and Irish working group, the Body Fluids Forum (BFF), highlighted the need to investigate different working practices prior to any inter-laboratory comparison work and identification of best practice. Various dilutions of semen were seeded onto swabs and cloth samples for each BFF member laboratory to test using their standard techniques. The results showed that the detection of acid phosphatase on swabs is best achieved using direct testing rather than on an extract from the swab. Extraction methods for spermatozoa require a balance to be achieved between using a sufficient volume of water to ensure optimal release and minimal volume to ensure a concentrated extract. PSA tests were investigated and found to be more sensitive than Choline. DNA profiles were obtained from samples in which no spermatozoa had been detected during microscopic examination.