Part III: Blood Lab – Reading a Blood Test

By Amy Neuzil, N.D. at People’s RX – April 1, 2015

In the quest to become a fitter, healthier, more vibrant, and more in-charge of your health individual, it is vital that you understand the basics about the labs your doctor routinely orders. We all want to be able to spot problems before they actually become problems, but it’s more the rule rather than the exception that doctors today have an average of seven minutes to spend in an office visit. Only the best ones will take the time to tell you that a particular number is creeping up toward abnormal. Typically if a number is normal, it’s normal; it has to get overtly out of range before you ever hear about it.  

In my past two articles, we’ve discussed the Complete Blood Count as well as the Comprehensive Metabolic Panel. Those are the most likely tests to be ordered routinely year after year. There are, however, a few tests that are commonly ordered that don’t fall within those two groupings. These include screening tests for thyroid, Vitamin D levels, and hemoglobin A1C. All of these tests are vital to your health, and it’s important to understand not only what normal conditions look like, but optimal.

Thyroid Stimulating Hormone

As you may deduce from the name, Thyroid Stimulating Hormone, or TSH, is not actually from the thyroid, but it stimulates the thyroid to produce hormones. Because the human body is cleverly designed to function on feedback loops, this is the most commonly used screening tool for thyroid function. If your actual thyroid hormones get too low, then TSH increases—thereby telling your thyroid to make more of the thyroid hormones. If your thyroid hormones get too high, then TSH falls. 

A high TSH indicates that your thyroid is sluggish or even under-functioning (as in hypothyroid). TSH that is too low might indicate that your thyroid is over-producing. The normal range is 0.4–4.0 milli-international Units per Liter (mIU/L). This is a reasonably broad range for many people, as symptoms start far before they fall outside of the “normal” range. Optimal levels indicate the range where most people feel best, have the most energy, and have adequate metabolism. Generally this is between 1.0–2.0 mIU/L. 

Many people will experience low thyroid symptoms when they are outside of the optimal range but within normal—important information to know if your doctor isn’t reporting it to you. 


Vitamin D

Vitamin D seems to be the golden child of modern medical research. It has been implicated in everything from fighting cancer and depression to predicting survival rates with heart disease and outcomes in Alzheimer’s. Clearly, Vitamin D is vital to our health and unfortunately overlooked within the medical system for a long time. Studies have shown that the majority of adults in North America are Vitamin D deficient and so more and more doctors are testing these levels as a part of their routine blood work. Most lab tests indicate that the normal range for Vitamin D is anywhere from 30–80 ng/mL; obviously a very broad range. The Mayo Clinic goes one step further to say that <10 ng/mL is a severe deficiency; 10–25 ng/mL is a moderate deficiency; 25–80 ng/mL is optimum levels; and >80 ng/mL runs the risk of toxicity. The difference between 25 ng/mL and 80 ng/mL is still significantly broad and many practitioners lean toward an optimal range being between 50–80 ng/mL instead.  


Hemoglobin A1C

In Part II of the March issue, I discussed glucose at length simply because it is one of the health numbers that, for most people, is entirely under their control. By working to keep it optimal, some of the most deadly diseases in the world can be prevented. Hemoglobin A1C is actually another, longer-term measure of blood sugars, or glucose. Glucose literally tests the sugars in your blood stream the moment the blood was drawn—it gives a very brief window into the whole picture. Hemoglobin A1C, or A1C for short, measures what percentage of the hemoglobin in your blood is “glycosylated,” or bound to sugar. 

A Hemoglobin A1C test actually provides a longer-term view of blood sugars and gives a good indication of how your average sugar levels have been for approximately the last six weeks. The normal range for A1C is between 4.5 and 6 percent. According to the Mayo Clinic, an A1C of 5 percent means your average blood sugar for past last six weeks was 97 mg/dL. (Normal glucose only goes up to 100 mg/sL, so that blood sugar level is beginning to creep toward the high end of the normal range.) An A1C higher than 6.5 percent on two separate occasions is diagnostic for diabetes. Results between 5.7 and 6.4 percent are considered pre-diabetes. Again, optimal is something else entirely; generally considered to be between 4.5–5.3 percent. 


It’s empowering to know your own blood test numbers so you have the capability to change them before they reach the pre-diabetes stage.

In regards to health, more knowledge means more chances to change for the better. Knowing the basics about your own blood work and striving to get into the optimal ranges can help to keep you fit, healthier, vibrant, and more in-charge of your health in the long run.



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