I've been working this out in my head and thinking of these things and here are the primary concerns I have:
ester identification: it would be easy to just underdose cyp or E if we are measuring too far out from the last pin
lack of a pharmaceutical control or a study to compare doses to. ISO, PP, TIPP just aren't used in studies that I can see
the protocol we all use is based on a study. The deviations from mean are just what was published. The groups are actually just 12 subjects. 61 people divided into 5 dosage groups.
so what we really need is mass spec, and since we all know how difficult that is we need to take steps to address the above concerns. Follow me here:
Here's my theory... All esters are going to peak in the first 24-36 hours. The faster ester will be a bigger peak so in 48 hours you are falling off peak. You measure an equal dose of each at 48 hours. You compare those numbers.
You repeat at 7 days because the faster ester should be significantly reduced. This gives a reasonable basis for deciding if the ester is what it's supposed to be.
The best you can do is assume the test is close if the two tests seem reasonable in their comparisons
pharmacy cyp is readily available to many of us since we are scripted cyp from our doctors. From here then we can establish a protocol of timing schedules, 48,72,96 hours after last pin. I have heard mention that OD has something of a recommendation here but I have not actually seen it.
The above is basically for pure esters. Several of us have been using 24hr after last pin to compare prop and tpa and although no true protocol exists, results from several vendors across the board seem to fall a little +/- a 7x multiplier.
For a blend like tipp, my best idea for a starting point is that we turn to those guys that we know are diligent about their own lab work that have been running tipp for quite awhile. The ones I've seen tend to be very consistent. Hopefully we can avoid the politics of source vs source when results come back higher or lower.
Obviously none of this is perfect, but in trying to think of all angles this is what I have come up with. Now I would like you guys to pick it apart.