[The main reasons behind variability in detection of prolactin and causes of true or apparent discordance with clinical state].

Both the "hook" effect and macroprolactinaemia, are the main reasons behind the discrepancy of serum prolactin level results in various laboratories. They can cause the diagnostic dilemmas or even completely faulty diagnosis resulting with undertaking of unnecessary investigations and/or an inappropriate method of treatment. Therefore, a review article on this matters may be of some help for clinical practice.