Why Fasting Glucose and HbA1C Are Not The Best Tests

Fasting Glucose and HbA1c Are Not The Best Tests

Your yearly trip to see the MD for 7 min and have him take a look at your blood work, may not be enough to determine your risks for diabetes, blood sugar abnormalities, and cardiovascular disease. 

I recently got asked about the health questionnaire from last week's Q & A. “My MD told me that my fasting blood sugar and HbA1C are completely normal, but I answered over 20 of the questions on your health questionnaire yes. How can I have all the symptoms of blood sugar imbalance but not have the blood work to prove it?”

In today's churn and burn medical offices most doctors are looking for a diagnostic test that they can get the most information the quickest and least invasive. It isn’t the MD’s fault that they have to see a patient ever 5-7 minutes. They have a huge liability, overhead, and let us be real, insurance reimbursement just won't pay for extended office visits that would allow your doctor an in-depth history and examination.

Yes, more than 7 minutes is considered extended. This is the reason that the medical profession uses mainly two tests when they are diagnosing diabetes or blood sugar irregularity.

These tests usually are fasting blood sugar and your hemoglobin A1C. Fasting blood sugar is just the amount of glucose circulating in your blood when you haven’t eaten for 8 or so hours. Hemoglobin A1C is slightly more complicated but still easy to understand.

Hemoglobin is an iron containing metalloprotein in your Red Blood Cells (RBC’s) that transports oxygen in our blood. We all understand that sugar is a pretty sticky substance when it is in a liquid form. Think syrup or honey, right?

So, what the HbA1C test is measuring is the amount of sugar that is bound or stuck to the hemoglobin. There are primarily two ways to increase the amount of sugar that is stuck to your hemoglobin, either have a lot of sugar in your blood, increasing the changes for it to bind together. Or if you RBC’s live a long time this will increase the overall exposure to sugar in your blood over time.

One of the significant problems with the HbA1C test is that it is set on the average lifespan of an RBC, which is 90 days. So, in theory this sounds great, it’s a way to measure the amount of sugar that has been in the blood over the last 90 days. Well, the problem comes when you actually look at how long RBC’s live in people with normal blood sugar levels vs. the ones with excess sugar in their blood.

A person with relatively normal blood sugar levels RBC can live up to around 140-150 days, while a person with higher blood sugar levels it can be as short as 81 days. This is a big deal because the longer the hemoglobin is exposed to sugar the more chances it has of becoming bound to sugar. Thus increasing the HbA1C test results. While this is an extremely useful test to determine how well managed a diabetic patient is it may not be the best marker for overall blood sugar balance and health.

So, then we have fasting blood sugar, all that tells you is whether or not the patient has hyper or hypo (high or low) blood sugar.

While, this is an essential test but not that diagnostic overall and probably the least predictive of your overall health and risk for diabetes and CVD. So the question is how do you determine if someone can regulate their blood sugar? And why did my patient have all the symptoms but none of the standard medical markers? Once upon a seminar that I was in the lecturer made an offhand comment about blood sugar that has stuck with me clinically for years.

“It’s not the relative amount of sugar, either high or low, that gives the patient symptoms. It is the rapid changes either do to their food choices or stress.”

And this is what we found with this patient. The best way to determine if a patient is regulating their blood sugar is to get a baseline of their blood sugar. This is done at home using a regular store bought glucose meter.

The testing is simple, take your blood sugar before a meal then every hour after a meal for at least three hours. In a well-balanced blood sugar patient, you will find that the total sugar goes up the first hour but not above 140 and not more than 40-50 points difference in any one hour of the test. If you have a fasting blood sugar in the 90’s to low 100’s and are eating a low carb diet, this may be considered normal, but on average your fasting blood sugar should be around 85-90.

So this is what we found with the patient that “failed” the questionnaire but had normal numbers. While his fasting blood sugar was “excellent” at 82  after he had eaten his blood sugar went relatively through the roof in the first hour, to 147 for an increase of 45 points.

Now granted this would also have been a red flag to the medical profession if they had done this test, which they didn’t. It makes him pre-diabetic because the first hour of the post meal glucose goes above 140.

This was a wake-up call for this patient who is relatively fit and takes care of himself by most standards but almost always rolls his eyes when I tell him to cut out the bread and simple carbs. I think I finally got through to him on this one. Wrapping this up we all need to do a better job of digging through our blood work, history, symptoms to figure out what is going on and not just trust that one blood test done at one static moment in time and a 7 min visit a year will keep you healthy. 

In today's medical environment you have to take responsibility for your health and dig deeper, to find the answers you are looking.  Hopefully, this article helps you find more was to determine how healthy you truly are.