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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:
In 2007, the results of one quality control study were published, which sent 3 samples to more than 1000 laboratories:
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).
- Nandrolone
- Boldenone
- Methyltestosterone
- And there are certainly other AAS as well
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
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).
