1. Need help with online free test calculator

I recently had tests done at Labcorp:

Total T -------- 693 ng/dL
Free T --------- 11.6 pg/mL
SHBG ---------- 50 nmol/L

So when I go to the online free testosterone calculator, and plug in Total T and SHBG, and leave albumin at the default 4.3, the calculator says I have free test of 11.8 ng/dL, which it says is 1.71% of total. At first that seemed really close, except that the units don't look right. The Labcorp free test is in pg/mL, but the calculator gives ng/dL. Making the conversion, my 11.6 pg/mL is 1.16 ng/dL, and that's 0.17% of total. So while it looks close at first, the calculator and the actual results are off by a factor of 10.

I'm having trouble making sense of this. The reason it's important is because I had total and free tests done four years ago, but did not have SHBG tested:

Total T -------- 763 ng/dL
Free T --------- 17.1 pg/mL

and I was hoping to calculate what SHBG must have been, assuming 4.3 for albumin. But it looks like everything is off by a factor of 10. What am I doing wrong here?

2. Originally Posted by peabody
I recently had tests done at Labcorp:

Total T -------- 693 ng/dL
Free T --------- 11.6 pg/mL
SHBG ---------- 50 nmol/L

So when I go to the online free testosterone calculator, and plug in Total T and SHBG, and leave albumin at the default 4.3, the calculator says I have free test of 11.8 ng/dL, which it says is 1.71% of total. At first that seemed really close, except that the units don't look right. The Labcorp free test is in pg/mL, but the calculator gives ng/dL. Making the conversion, my 11.6 pg/mL is 1.16 ng/dL, and that's 0.17% of total. So while it looks close at first, the calculator and the actual results are off by a factor of 10.
I'm having trouble making sense of this. The reason it's important is because I had total and free tests done four years ago, but did not have SHBG tested:

Total T -------- 763 ng/dL
Free T --------- 17.1 pg/mL

and I was hoping to calculate what SHBG must have been, assuming 4.3 for albumin. But it looks like everything is off by a factor of 10. What am I doing wrong here?
Screw the calculator your SHBG is too high and its bounding up your testosterone levels.
Find out why SHBG is high or if you are on HRT then increase dosage or add danazol 25 mgs a day. IF you are not on HRT then danazol will not help and will TT bring levels down. I have seen multiple cases of drs trying to do this and fail..I have a case of where a guy has TT of 1495 with shbg of 150 !! no TRT...Where is your e2 (proper reading not sensitive essay but 004515) estrogens (xeno or estrodial) can raise SHBG as can thyroid.
Basically we live in a toxic world and it is killing us slowly by altering gene expressions ....
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3. I'm not on TRT. E2 is 16.7 on the 4515 test.

What I'm trying to do is compare the numbers from 4 years ago, when I didn't have symptoms, to the current ones. But I didn't test for SHBG back then, so I was trying to calculate what SHBG was using the online calculator.

4. I calculate your SHBG at 34nmol/L four years ago.

5. That's what I got too, but then I realized that the value for free T was off by a factor of 10. The Labcorp test gives free T in pg/mL, but the issam.ch online calculator uses ng/dL. So the 17.1 free T value there is 10 times as large as my test results. And actually, the issam result matches their calculation of about 2% of test being free, which is what you read everywhere, whereas the Labcorp values would give 0.2% free.

But if you read Morgentaler's book, he talks about free T below 15 pg/mL as being low, so he's using the same test as Labcorp.

I think the calculator is just based on a different test for free T than Labcorp and Morgentaler use. I just don't know if the relationship between the two is actually 10:1.

In any case, 17.1 ng/dL per the calculator is equal to 171 pg/mL, which is ten times my test result for free T.
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