• All new members please introduce your self here and welcome to the board:
    http://www.professionalmuscle.com/forums/showthread.php?t=259
Buy Needles And Syringes With No Prescription
M4B Store Banner
intex
Riptropin Store banner
Generation X Bodybuilding Forum
Buy Needles And Syringes With No Prescription
Buy Needles And Syringes With No Prescription
Mysupps Store Banner
IP Gear Store Banner
PM-Ace-Labs
Ganabol Store Banner
Spend $100 and get bonus needles free at sterile syringes
Professional Muscle Store open now
sunrise2
PHARMAHGH1
kinglab
ganabol2
Professional Muscle Store open now
over 5000 supplements on sale at professional muscle store
azteca
granabolic1
napsgear-210x65
esquel
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store
advertise1
UGFREAK-banner-PM
tjk
yms-GIF-210x65-SB
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store
over 5000 supplements on sale at professional muscle store

Measuring TST Levels in Blood Tests

astar

Member
Registered
Joined
Apr 24, 2024
Messages
91
Measurement of TST levels in blood is most commonly done using immunoassays, which are quite inaccurate and can also be influenced by the presence of other used AAS. Why are immunoassays used to measure TST levels in blood if they are so inaccurate? Because they are cheap. These tests are based on binding to antibodies. In these tests, there is a limited amount of antibodies, so the maximum upper limit of TST concentration is around 60 nmol/l, higher levels are already immeasurable. Also, the problem with antibodies is that they also bind to other molecules that have a similar structure to TST, resulting in completely distorted results, we call it cross-reactivity. It has been found in practice that there are AAS that cause this cross-reactivity, specifically:
  • Nandrolone
  • Boldenone
  • Methyltestosterone
  • And there are certainly other AAS as well
Yes, you understood correctly, that if you were to have blood tests done to determine your TST level and were using Boldenone or Nandrolone along with TST, the TST levels would be high, but it wouldn't be an accurate reading. We can talk about cross-reactivity in tens of percentages.

In 2007, the results of one quality control study were published, which sent 3 samples to more than 1000 laboratories:
  • Sample No.1 = had the expected TST concentration for a healthy woman the average result from the laboratories was 33 ng/dl
  • Sample No.2 = had the expected TST concentration for a healthy man the average result from the laboratories was 465 ng/dl
  • Sample No.3 = had the TST concentration of a hypogonadal man the average result from the laboratories was 97 ng/dl
All samples contained artificial blood with the same amount of TST appropriate to the respective group. The average results are quite good, but let's look at the difference between the results from different laboratories. For example, one laboratory measured a result of 45 ng/dl for sample No.3, and another laboratory measured 365 ng/dl for the same sample. That's an 8-fold difference! Looking at the deviation between individual tests for sample No.3, it was 31 ng/dl, what does that mean? That roughly 1/4 of the tests for sample No.3 measured below 66 ng/dl or above 128 ng/dl. These are quite significant differences, keep in mind that all laboratories received the same samples with the same TST content, and one of them measured a value of 45 ng/dl while another measured 365 ng/dl? That level of inaccuracy is staggering.

Looking at sample No.2, the lowest measured value was 276 ng/dl and the highest was 744 ng/dl. The deviation was determined to be 81 ng/dl, which means that 1/4 of the tests for sample No.2 measured below 384 ng/dl or above 546 ng/dl. Again, very inaccurate results. The difference in results is also influenced by the calibration of the measuring machine and also by the manufacturer of the machine (Bayer X, Roche Y, DPC Z). So the truth is, if today you received a blood test result of 400 ng/dl and a month later a result of 500 ng/dl, it may not at all mean that your TST has increased. But unfortunately, that's the case. It's also interesting that even if you were to perform the same test three times in a row on the same sample using the same machine, each test result could be vastly different 🙂 what more can be said about that.

Another often overlooked factor is that TST levels in blood are not static and change over time, understandably. Blood collection is usually done in the morning on an empty stomach, as you all know, that's fine, but if you're using AAS, there's a difference whether you apply them one, two, or for example three days before the blood test. Many of you go for blood tests with the assumption that for the first blood test you applied TST one day before collection and for the second blood test a month later you applied TST four days before collection, which is of course nonsense if you want to compare these results and draw a reasonable conclusion.

Alright, so we know that immunoassay blood tests are very inaccurate, are there more accurate tests? Yes, of course. These are tests conducted using liquid chromatography with tandem mass spectrometry (LC-MS/MS).
 
Even though there are concerns about the accuracy of standard testosterone blood tests, they still have value. They can help track changes in your testosterone levels over time and identify extreme cases of high or low levels. While they may not be perfect, they are widely available and affordable. Doctors also consider other factors like your symptoms and medical history, using the blood test as one piece of the puzzle. So, they can still be useful when combined with other information and professional medical advice.
 

Forum statistics

Total page views
564,282,588
Threads
136,401
Messages
2,797,621
Members
160,720
Latest member
Bigdaddygriff77
NapsGear
HGH Power Store email banner
yourdailyvitamins
Prowrist straps store banner
infinity
FLASHING-BOTTOM-BANNER-210x131
raws
Savage Labs Store email
Syntherol Site Enhancing Oil Synthol
aqpharma
yms-GIF-210x131-Banne-B
hulabs
ezgif-com-resize-2-1
MA Research Chem store banner
MA Supps Store Banner
volartek
Keytech banner
musclechem
Godbullraw-bottom-banner
Injection Instructions for beginners
Knight Labs store email banner
3
YMS-210x131-V02
YMS-210x131-V02
Back
Top