Its principal physiological perform is to fabricate the fluid that nurtures spermatozoa. What occurs to certainly one of its precept prostate-specific proteins in serum upon ejaculation might sound a wise first step in finding out using a serum take a look at.
Given that PSA is usually measured, that 1000’s of papers are revealed on PSA every year, and tens of millions of assessments accomplished, one may assume that the results of primary physiological modifications can be effectively sorted out. Not so.
When an assay is only a guess
To reply the query concerning the impact on PSA of ejaculation, it’s essential to enter the arcane world of immunoassays and their properties.
Any assay is designed to measure one thing inside sure focus limits. For commonest PSA assays, this implies values between about 1 to 100 µg/L. Samples with increased concentrations could be diluted to be inside this vary.
But concentrations of lower than 1 µg/L are in part of the assay the place important inaccuracies could be anticipated, and beneath about 0.5 µg/L any worth obtained is little higher than a guess (although there are some `super-sensitive’ assays which might measure very low values). Many of the articles look at populations with very low PSA ranges.
What is the query?
PSA shall be measured in lots of medical conditions (like after operation for prostate most cancers) the place ejaculation is unlikely to be a difficulty. But the place prostate most cancers is only a suspicion a serum PSA may effectively be a part of the diagnostic routine in a person who’s sexually energetic.
Knowing whether or not and the way ejaculation impacts serum PSA shall be essential. We are most involved with results in older males (over 50) whjo have, and who would not have, prostate most cancers or benign hyperplasia, as a result of these are the individuals almost certainly to be examined. How lengthy after ejaculation do any results final? That will have an effect on the interpretation and usefulness of the take a look at.
Many articles look solely at younger males, and at instances early after ejaculation. Those that take a look at older males usually exclude these with prostatic illness.
Where’s the proof?
Bandolier carried out a MEDLINE seek for papers which examined ejaculation and serum PSA. We discovered 9. The particulars are proven within the Table. None of the articles commented on the power of the assays used to measure low values of PSA.