Thursday, November 10, 2011

Measuring Testosterone Levels in Men

While comparing with female menopause, in men, the fall in sex hormone production is much more gradual, developing over decades rather than months or years. Mental and physical changes can occur, but they are much more subtle in onset and can easily be missed.  Therefore, some experts claim that the term “male menopause”, or andropause, is not strictly accurate and does not reflect changes in men as a process. Instead, they prefer to talk about “partial androgen deficiency of the ageing male” (PADAM).

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How is androgen deficiency (PADAM) diagnosed?

No definitive tests for PADAM exist yet. Low blood levels of testosterone alone are insufficient to make the diagnosis, however they may lead to the raise awareness on the potential health problems source. The combination of several different suggestive symptoms and physical signs, together with low blood levels of testosterone, should raise suspicion that PADAM is present.

There are a few methods employed to determine if a man has indeed a low amount of testosterone in his body. The first method is for the physician to take a complete medical history of the patient. The doctor will be looking for signs and symptoms of androgen deficiency. The patient will be asked questions about their sex life, poor erections, less volume of semen, orgasmic quality, decreased energy, loss of muscle strength, self-esteem problems, depression, tiredness, irritability, insomnia, sweating, hair loss and abdominal weight gain. Other important symptoms include a high LDL cholesterol number, osteoporosis, an increase in total body fat and a reduction of red blood cells in the plasma. For many men, premature aging is a form of hypogonadism. Although there are more symptoms than listed here, the line of questioning will be the same in the doctor's office. From the information provided here, it shows how important it is to verify the diagnosis since so many of these symptoms can relate to other diseases.

After determining that the symptoms seem to suggest low testosterone, you will be required to have your testosterone measured using a Testosterone blood test. The two relevant blood tests are the Total Testosterone and the Free Testosterone tests. Most anti-aging doctors recommend taking the blood draw in the morning, usually before 10:00 a.m. This is when the male's testosterone level is at its highest point. Several blood tests should be performed over a period of a week to determine the actual number when trying to diagnose andropause. The levels of testosterone tend to fluctuate throughout the day. Once results are confirmed, there are several options the person can consider and discuss with their doctor regarding the testosterone delivery system will work best for them.

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The problem with measuring testosterone levels

It would be comforting to think that a simple blood test could identify androgen deficiency. Unfortunately, this is not the case. Widespread disagreement exists over what is the normal range of testosterone levels and what, exactly, should be measured in the blood to assess androgen deficiency.

The existing “normal” range for total testosterone is based upon statistical analysis of pooled samples from all men, including those who might have PADAM. So, the “normal” testosterone levels are not necessarily the same, as the healthy levels.

Testosterone is released into the bloodstream in pulses, and levels vary through the day (diurnal variation). In general, the testicles release more testosterone in the morning than later in the day. Blood samples should therefore be taken between 8am and 10am, as we mentioned earlier. Therefore, multiple separate, consistent results are recommended to establish that there is a problem with testosterone levels.

About 60-70 per cent of the total testosterone is tightly bound to a protein, present in the blood, called sex hormone binding globulin (SHBG). This protein-binding is a common way in which hormones are transported in the bloodstream and it is effectively a circulating store of testosterone. The testosterone only becomes active when the link to SHBG is broken, and this is a process which occurs at a certain rate all the time. Older men produce relatively more SHBG, as do heavy drinkers and men with thyroid disorders, thus reducing the amount of “free” testosterone.

Another 30-40 per cent of the total testosterone is more loosely bound to another protein, called albumen. Testosterone bound to albumen is also inactive, so free testosterone probably accounts for only 1 to 2 per cent of the total.

Measurement of total testosterone is therefore a poor measure of active testosterone. Free testosterone levels are expensive to measure and are not widely available.

Free Androgen Index (FAI = total testosterone/SHBG x100) is an alternative measure of androgen state that is not as reliable as free testosterone, but is better than relying solely on total testosterone.

How the Test Is Performed

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

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The normal values listed below are called a reference range and should be used for the mere guidance. These ranges vary from lab to lab, and your lab may have a different range for what’s normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Several sources for the reference range were indeed different, when I tried to compare them. There are the data from two sources:
  1. Source One:
·         Total Testosterone: 270-1070 ng/dL (9-38 nmol/L)
·         Free Testosterone: 50-210 ng/mL (174-729 pmol/L)

  1. Source Two:
·         Total Testosterone:
19-49 years old 249-836 ng/dL
50 years and older 193-740 ng/dL
·         Free Testosterone: 32-168 pg/mL
·         Free Androgen Index: 30-150

Sources and Additional Information:

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