Trucker MD
Why the A1C test for drivers?
Understanding your blood sugar level is important for your CDL and your long-term health

By John McElligott, MD
Land Line contributor


Suppose a driver goes in for a DOT exam and his/her urine specimen indicates sugar “spilling” on the routine test. What does this mean?

The normal kidney can hold up to a 300 mg percent rise in blood sugar without spilling sugar into the urine. If sugar is detected in that urine specimen, here’s what happens next.

Usually, a medical examiner will order a “finger stick” to determine the blood sugar level. If the test comes back with a reading of 160 mg percent or higher, then the driver is diagnosed with new onset diabetes mellitus or uncontrolled diabetes that needs better treatment.

Such a diagnosis can lead to loss of a professional driver’s DOT medical card or a three-month medical card.

The driver must see his doctor – if he has one – and be treated or have his medication adjusted.

Then the driver must demonstrate to the DOT examiner (soon to be “certified medical examiner”) that his blood sugar is being treated. It must also be demonstrated that the driver is compliant with follow-up and is taking medication for his disease.

Here is where the A1C test is going to be a life-changer for professional drivers.

The number that most of us DOT medical examiners look for is an average blood sugar of 160 or less. But how do we find the average blood sugar when we have only three months to demonstrate compliance?

The answer is a test called “hemoglobin A1C.” This test measures the glucose found in the red blood cells. It just so happens that the human red blood cell lives for 120 days, so we can measure the sugar in it.

DOT medical examiners now have either instant A1C in office test or, at worst, a two- to three-day send-out test.

The good news is that the A1C instant test done at the time of a DOT physical can save your ticket to the dance. It provides enough information to put your average 90-day blood sugar into play, which could counteract the test for sugar in the urine and the finger stick, both of which are a snapshot in time.

So what else do you need to know about the A1C test?

  1. Make sure your examiner uses the instant A1C test to help you stay on the road.
  2. If you are diabetic, never eat before going in for a DOT medical exam.
  3. Take your medicine on a regular schedule.
  4. Get an A1C test from your doctor at least three months before your DOT exam is due and keep a copy to show the examiner.
  5. If your test shows that your average blood sugar is well-controlled, then continue the same routine every year.

Remember: Medication alone does not treat diabetes. The cornerstone of treatment is diet and exercise. LL

Editor’s note: John McElligott is an M.D. and Fellow of the American College of Physicians.