Blood Testing - why?
Most people don’t do any blood tests until they get ill and are forced to go through a health checkup, or are already diagnosed with metabolic syndrome, cardiovascular disease or diabetes etc. This is unfortunate, because regular blood testing is the single best strategy to stay healthy thought life. In this article I will explain why you want to get your blood tests and which ones to get.
Blood testing – What for? When?
The main reason to start doing regular blood testing at a young age when you are at your peak it to establish your individual healthy baseline. Reference ranges that are printed in lab result reports are just that – a reference. The range of values in the reference range – aka the “normal range” – only shows the distribution of values in a population, not what is optimal for a particular individual. Also, normal ranges are often very wide. For ex. for total testosterone, the male normal range spans all the way from around 300 to 1,200 ng/dL. The female range is smaller, 10-60 ng/dL , but low vs high testosterone levels within this range can still have significant implications for women. (Note that for testosterone, the normal ranges vary vastly between different laboratories and assays). Other parameters with wide normal ranges are DHEA, TSH (thyroid-stimulating hormone) and the gonadotrophins (LH and FSH).
For men, it is especially important to check their testosterone levels at a young age, because of its wide normal range. Due to differences in androgen receptor sensitivity, among men having the same testosterone level, some can be suffering hypogonadal symptoms and metabolic disturbances while others are perfectly fine.[3-6] This is the great dilemma in diagnosing testosterone deficiency (aka hypogonadism or Low-T). If you know what your testosterone level was when you were young, you can track the decline and see how much it has fallen over the years. This will provide invaluable information for you and your doctor when it comes to dosing testosterone replacement therapy, if you were to end up with testosterone deficiency.
For women, it is especially important to monitor thyroid levels, as hypothyroidism – both overt and subclinical - is more common in women than men [7, 8] and may contribute to women’s propensity to gain body fat more easily than men.[9-13] The prevalence of overt and subclinical hypothyroidism is 5% and up to 20%, respectively.[8, 14] Checking the thyroid is critical for women who desire pregnancy, as both overt and sub-clinical hypothyroidism can have an adverse impact on fetal development and cause miscarriage. Another female issue, hypoactive sexual desire disorder, can be – at least partly – caused by low testosterone levels. Low testosterone also has other detrimental effects in women (for more on that see our previous article “Testosterone in women - is it physiological and clinically important?”.  Thus, it is equally important for women to check their testosterone levels as it is for men to check their estrogen levels.
Thus, the only way to find out what is optimal for you as an individual is to do blood testing when you are young and healthy. This will be invaluable when you get 20+ years older and start to experience health issues, as it will show you what parameters are off, and give clues to what went wrong and what treatment will be best for you. A fool proof investment in your health!
If you read this and are already in your middle-age, ask yourself how long ago did you last have your blood test done? Even though you have passed your peak, it is never too late to find out your health status. And the sooner you do, the greater the likelihood you may detect and do something about it before it’s too late.
What labs to get?
What follows is a list of panels you want to get checked on a regular basis as part of your health screening.
Comprehensive metabolic panel (CMP)
- How your kidneys and liver are working
- Blood sugar (aka blood glucose) and calcium levels
- Sodium, potassium, and chloride levels (called electrolytes)
- Protein levels
Complete blood count (CBC)
FOR HEALTH PROMOTION
Hormones and Gonadotrophins
Fasting or not?
Where to get your blood test order (requisition)?
1. Bhasin, S., et al., Reference ranges for testosterone in men generated using liquid chromatography tandem mass spectrometry in a community-based sample of healthy nonobese young men in the Framingham Heart Study and applied to three geographically distinct cohorts. J Clin Endocrinol Metab, 2011. 96(8): p. 2430-9.
2. Haring, R., et al., Age-specific reference ranges for serum testosterone and androstenedione concentrations in women measured by liquid chromatography-tandem mass spectrometry. J Clin Endocrinol Metab, 2012. 97(2): p. 408-15.
3. Crabbe, P., et al., Part of the interindividual variation in serum testosterone levels in healthy men reflects differences in androgen sensitivity and feedback set point: contribution of the androgen receptor polyglutamine tract polymorphism. J Clin Endocrinol Metab, 2007. 92(9): p. 3604-10.
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