Free Testosterone Lab Test Range: Quest vs LabCorp Results

[S1W]

I was looking through some labs and feeling like I'm comparing apples to oranges and if so, how to interpret things.

On a pre-TRT lab from Quest, the "Free Testosterone" reading is 51.3 pg/ml (range 35.0-155.0 pg/ml)

On a post-TRT follow up lab from LabCorp, the "Free Tesosterone (Direct)" reading is 25.2 pg/ml (range 8.7-25.1 pg/ml).

How would I compare theses two results to see what kind of progress I've made?

 

[Virginian]

That's incredible. The ranges from the two labs are totally incompatible. They are clearly not measuring the same thing.

However, your free T moved from the bottom of the range before TRT to the top of the range with TRT. From what I have read, free T is really more important than total T.

So you are doing great! Are you noticing any good effects?

 

[S1W]

That's incredible. The ranges from the two labs are totally incompatible. They are clearly not measuring the same thing.

However, your free T moved from the bottom of the range before TRT to the top of the range with TRT. From what I have read, free T is really more important than total T.

So you are doing great! Are you noticing any good effects?

So far so good. I've only been on for a few months but have noticed some subtle effects, both good and bad.

Good: Slightly more energy, slightly better mood, better/more productive workouts, perhaps greater interest in hobbies.

Bad: Painful acne on back of head, what was mild ED actually got worse, lower libido, testicular atrophy.

Yes, I would agree that at a glance the two labs do appear incompatible, however I bet one of the gurus on this site will be able to explain to us what we're missing.

 

[Systemlord]

Four weeks into TRT at the end of every week (once weekly injections) I would notice insane erections that were incredibly sensitive that only happened once each week, then 2 months nothing, then they started showing up again only to disappear yet again.

It took me 7 months for significant changes in erections and my libido was high months earlier, erections are almost 100 percent and probably a couple more months for full sensitivity and an increase in total spontaneous erections.

It's going to take time for your body to heal, there will be times when you question if you are getting better at all, do fall into this trap as it will only make you miserable.

 

[S1W]

Four weeks into TRT at the end of every week (once weekly injections) I would notice insane erections that were incredibly sensitive that only happened once each week, then 2 months nothing, then they started showing up again only to disappear yet again.

It took me 7 months for significant changes in erections and my libido was high months earlier, erections are almost 100 percent and probably a couple more months for full sensitivity and an increase in total spontaneous erections.

It's going to take time for your body to heal, there will be times when you question if you are getting better at all, do fall into this trap as it will only make you miserable.

Thanks Systemlord - always good to hear the experiences of people who have been on this path longer than I have. I get that I am still in the early stages and have a while to go before I see real results (although I have to admit I am surprised by worsening ED and decreased sensitivity). Am I reading your post right that you also experienced decreased erection quality and sensitivity during the early stages, and then later had significant improvements?

For the original question - anyone understand the difference between those two labs?

 

[Systemlord]

Thanks Systemlord - always good to hear the experiences of people who have been on this path longer than I have. I get that I am still in the early stages and have a while to go before I see real results (although I have to admit I am surprised by worsening ED and decreased sensitivity). Am I reading your post right that you also experienced decreased erection quality and sensitivity during the early stages, and then later had significant improvements?


For the original question - anyone understand the difference between those two labs?

What's happened is your pituitary gland detects T circulating in the blood and assumes your testes are producing T again and throttles back LH which tells the testes to produce T, the longer you are injecting T the pituitary gland with shut down the feedback loop that is the HPTA will stop until such time you stop TRT. My erection quality was poor before I started TRT, but after starting TRT it became worse which has to do with your pituitary gland shutting down.

You have seized control of your HPTA system and you're waiting for TRT to work which can take many months, individual cases can take up to 1 year for erections to return, most have it happen sooner. There are some who's doctors aren't monitoring properly and waste valuable time with their E2 out of range, for erections to occur your E2 levels can't be to low or too high. I would estimate between 20-40 pg/mL, everyone's different though.

You can't compare between different labs, their ranges aren't compatible. If you were to take the same blood sample and give it to 2 different labs technicians you would get different results, there are so many variables, skill and errors create more of a best guess than actual result.

 

[madman]

Thanks Systemlord - always good to hear the experiences of people who have been on this path longer than I have. I get that I am still in the early stages and have a while to go before I see real results (although I have to admit I am surprised by worsening ED and decreased sensitivity). Am I reading your post right that you also experienced decreased erection quality and sensitivity during the early stages, and then later had significant improvements?

For the original question - anyone understand the difference between those two labs?

Many other factors aside from healthy testosterone levels can effect erection function/quality/sensitivity.

What is your protocol- (testosterone dosage/injection frequency) any use of hcg/a.i. (aromatose inhibitor)?

Higher weekly doses of testosterone cause a quicker shutdown of your hpta which is basically shutdown within 5-6 weeks on 100mg/week and within 2 weeks on a dose of 250-500mg/week. https://www.ncbi.nlm.nih.gov/pubmed/9394096

 

[madman]

It is common for many to start trt at 100mg/week and many notice what one would call the honeymoon period at the beginning of therapy as you are still producing endogenous testosterone to a certain degree and are also injecting exogenous testosterone.

Once hpga shutdown occurs most will experience a crash which they will rebound from once testosterone levels stabilize(usually 6 weeks) due to the weekly injections of exogenous testosterone.

Regarding overall improvements in low t symptoms it takes time and everyone responds differently. Testosterone is critical to erectile tissue health/function and libido but is only one piece of the puzzle as many other factors can effect ones libido (neurotransmitters/estradiol levels/stress/quality of sleep/underlying health issues).

Many factors can also effect erectile health/function (vascular/endothelial health/estradiol levels/stress/quality sleep/thyroid function/underlying health issues).

Testosterone will improve NO (nitric oxide) along with improvements in the function/health of erectile tissue (which contains AR receptors).

Improvements may take longer in some than others but even than there is no guarantee that it will cure every ones issues regarding erectile function/health as I stated earlier many other factors can contribute to ones overall outcome.

One could have healthy total t/free t levels along with other hormones in balance and still suffer from issues regarding erectile function as vascular/endothelial health of the individual plays a critical role in the overall health/function of erections and hence why there are many on trt using PDE5 inhibitors (viagara/cialis/levitra).




Effects of Chronic Testosterone Administration in Normal Men: Safety and Efficacy of High Dosage Testosterone and Parallel Dose-Dependent Suppression of Luteinizing Hormone, Follicle-Stimulating Hormone, and Sperm Production *

 

[S1W]

What is your protocol- (testosterone dosage/injection frequency) any use of hcg/a.i. (aromatose inhibitor)?

For several months now, I have been using 200mg/g compounded cream, 1/2 gram daily - so 100mg/week. Some key numbers from my labs 2 months in:

Total T: 795 ng/dl (range 264-916)
Free T: 25.2 ng/dl (range 8.7-25.1)
Estradiol, Sensitive: 38.4pg/ml (range 8-35)
SHBG: 26.9 nmol/l (range 16.5-55.9)

Really I was somewhat happy with the results I was getting from the cream, and liked the simplicity of the once daily application and no HCG or AI.

Regardless, I switched doctors and was recently given a protocol change to T. Cyp 64mg E3.5D (128mg/week) with HCG 350IU E3.5D (700IU/week). My biggest unanswered question with this new protocol would be if it is more or less likely to effect aromitization compared to my previous protocol of compounded cream once daily. I am someone who may be particularly sensitive to E2 - I had gyno issues/surgery as a teenager, and since adopting this new protocol, the nipples have been tingly. Also noticed poorer erectile function on the new protocol...but it has only been a week so perhaps too soon to say.

 

[madman]

For several months now, I have been using 200mg/g compounded cream, 1/2 gram daily - so 100mg/week. Some key numbers from my labs 2 months in:

Total T: 795 ng/dl (range 264-916)
Free T: 25.2 ng/dl (range 8.7-25.1)
Estradiol, Sensitive: 38.4pg/ml (range 8-35)
SHBG: 26.9 nmol/l (range 16.5-55.9)

Really I was somewhat happy with the results I was getting from the cream, and liked the simplicity of the once daily application and no HCG or AI.

Regardless, I switched doctors and was recently given a protocol change to T. Cyp 64mg E3.5D (128mg/week) with HCG 350IU E3.5D (700IU/week). My biggest unanswered question with this new protocol would be if it is more or less likely to effect aromitization compared to my previous protocol of compounded cream once daily. I am someone who may be particularly sensitive to E2 - I had gyno issues/surgery as a teenager, and since adopting this new protocol, the nipples have been tingly. Also noticed poorer erectile function on the new protocol...but it has only been a week so perhaps too soon to say.

Estradiol will increase in both treatment methods (transdermal/injectable) and ones testosterone levels will have a bigger effect on increasing e2 as the higher the testosterone levels the higher the aromatization into estradiol.

You may very well hit a higher total t/free t with the injectable as oppose to your transdermal protocol which could push your e2 higher.

If anything your hematocrit/hemoglobin may increase more on injectable but even than testosterone dose plays a role.

Comparison of the Effects of Testosterone Gels, Injections, and Pellets on Serum Hormones, Erythrocytosis, Lipids, and Prostate-Specific Antigen

 

[madman]

Onset of effects of testosterone treatment and time span until maximum effects are achieved

 

[madman]

Thanks Systemlord - always good to hear the experiences of people who have been on this path longer than I have. I get that I am still in the early stages and have a while to go before I see real results (although I have to admit I am surprised by worsening ED and decreased sensitivity). Am I reading your post right that you also experienced decreased erection quality and sensitivity during the early stages, and then later had significant improvements?

For the original question - anyone understand the difference between those two labs?

PubMed Central, Figure 4: Eur J Endocrinol. 2011 Nov; 165(5): 675–685. doi: 10.1530/EJE-11-0221

 

[Vince Carter]

You cannot compare numbers across labs, can't be done. If you want to compare things, use one lab.

 

[Nelson Vergel]

Differences Between LabCorp and Quest Sensitive Estradiol and Testosterone Lab Test Ranges

The Labcorp results are from January and the Quest results are from this week. The ranges they use are different so I’m not sure how to compare them. Do these seem pretty much in line? Especially the “Free Test” difference. Quest is the one in color, FYI Also, how do you guys feel about the E2...

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