Test prolactin at peak or trough? Time of day? Fasting?

[RickB]

What parameters for getting the most accurate reading?

 

[Cataceous]

The standard advice is to fast in the 12 hours before the test and abstain from sexual activity in the 24 hours before. This usually makes a morning draw the obvious time. Interestingly one study says that prolactin can be a lot higher at night than during the day. There are some suggestions that if you have the test too soon after waking then you will catch the taper of the nightly peak. I haven't come across any comments on whether the timing of TRT dosing is important.