Testosterone assay experts... puzzling results

[Blackhawk]

I am following up on my most recent protocol: Daily T cyp/prop results

I am taking T cyp/prop blend at 4:3 ratio, 56mg daily, and HCG 400iu E4D. I wanted to see peak and trough, so got two blood draws. One was covered by insurance through labcorp, the other I bought on discounted labs since it is cheaper.

The higher levels are from the theoretical trough before injection on the morning of both T and HCG injection, so even if there's any LH stimulation, it should be true trough.

The lower (ironically: peak) levels were taken roughly 4 hours after T injection and 28 hours after HCG injection, which by Dr Saya's small HCG blood level study would put me about peak for HCG too.

What is going on here? Is there that much difference in Labcorp vs Quest, or lab error or what?

Peak:




Trough:

 

[Cataceous]

I'm not sure what to make of it. The Labcorp total testosterone assay is definitely standardized. I'm not sure about the Quest assay. Quest is now listed as having a certified assay, but it's unclear to me if Quest and Med Fusion are interchangeable. Of course having your assay standardized doesn't preclude screwing up individual tests. Do you have an idea of what your SHBG level is? Calculated free testosterone would be an interesting point of comparison.

 

[Blackhawk]

I'm not sure what to make of it. The Labcorp total testosterone assay is definitely standardized. I'm not sure about the Quest assay. Quest is now listed as having a certified assay, but it's unclear to me if Quest and Med Fusion are interchangeable. Of course having your assay standardized doesn't preclude screwing up individual tests. Do you have an idea of what your SHBG level is? Calculated free testosterone would be an interesting point of comparison.

Thanks, I should be getting SHBG and E2 results back soon, taken at the same time, and get ongoing regular CBCs, so know where albumin runs. I have sent a request to my PCP with explanation asking for another test to redo trough.

 

[Blackhawk]

Followup,

I retested trough with Quest LC/MS, equilibrium dialysis. Seems more in line. I still don;t know how to interpret vermuelen in context with Quest and Tru-T (below):

Vermuelen:

Tru-T:

Free Testosterone:
0.95 nMol/L
27.27 ng/dL

 

[tareload]

I am following up on my most recent protocol: Daily T cyp/prop results

I am taking T cyp/prop blend at 4:3 ratio, 56mg daily, and HCG 400iu E4D. I wanted to see peak and trough, so got two blood draws. One was covered by insurance through labcorp, the other I bought on discounted labs since it is cheaper.

The higher levels are from the theoretical trough before injection on the morning of both T and HCG injection, so even if there's any LH stimulation, it should be true trough.

The lower (ironically: peak) levels were taken roughly 4 hours after T injection and 28 hours after HCG injection, which by Dr Saya's small HCG blood level study would put me about peak for HCG too.

What is going on here? Is there that much difference in Labcorp vs Quest, or lab error or what?

Peak:




Trough:

View attachment 31939

You have to consider the Tmax (time to reach peak) for the respective components. Tmax may be 4 to 6 hrs (longer?) for TP but could be 18 to 36 hours for TC based on your apparent clearance and volume of distribution. Then there's the same for hCG.

For example, old Testaviron graph but the peaks are way off according to my results:

So I don't think your measurement time points are quite reflective of true peak and trough. But that's right you are doing ED injections so with your 4/3 ratio it should be not too far off. Thanks for sharing.

 

[tareload]

Followup,

I retested trough with Quest LC/MS, equilibrium dialysis. Seems more in line. I still don;t know how to interpret vermuelen in context with Quest and Tru-T (below):

View attachment 32861



Vermuelen:
View attachment 32862


Tru-T:

Free Testosterone:
0.95 nMol/L
27.27 ng/dL

Yes this makes sense and of course Vermeulen owning TruT and within 20% of equilibrium dialysis as usual.

 

[Blackhawk]

You have to consider the Tmax (time to reach peak) for the respective components. Tmax may be 4 to 6 hrs (longer?) for TP but could be 18 to 36 hours for TC based on your apparent clearance and volume of distribution. Then there's the same for hCG.

For example, old Testaviron graph but the peaks are way off according to my results:

View attachment 32863

So I don't think your measurement time points are quite reflective of true peak and trough. But that's right you are doing ED injections so with your 4/3 ratio it should be not too far off. Thanks for sharing.

I know that the timing may be off, but first round of tests at 8 weeks after starting looked pretty good
as representative at least of a daily swing. The Quest labs here are at least in agreement on the higher level mid day compared to morning before injection. I still don't know what to make of the Labcorp results.

I found the Vermuelen reference range, looks more consistent with this info:

 

[tareload]

I know that the timing may be off, but first round of tests at 8 weeks after starting looked pretty good
as representative at least of a daily swing. The Quest labs here are at least in agreement on the higher level mid day compared to morning before injection. I still don't know what to make of the Labcorp results.

I found the Vermuelen reference range, looks more consistent with this info:

View attachment 32864

I ran Labcorp and Quest head to head and good agreement...

Gory details:

See both Parts I and II
Calculate free testosterone with TruT by FPT

go Team Vermeulen!