Fasting Glucose test, variations possible?

Factual Questions
1

Last Saturday morning, kaylasauntie and I took Michaela to a lab for a blood draw for a fasting glucose test to rule out diabetes. The experience was not a happy one for my (almost) nine-year old. The phlebotomists had a difficult time getting the needle into her vein. In fact they never succeeded, and after trying for over fifteen minutes in both arms, it was decided to send for a technician from Respiratory Therapy (we took her to the hospital to get this done) to perform an arterial blood draw.

We waited about thirty more minutes before the RT tech arrived, which gave Michaela some time to calm down, and she was in fairly good spirits when the tech arrived and introduced himself. He got her back into the chair and stuck the needle deep into her right arm. He probed for her artery, a painful process that put Michaela back into panicky pain mode. It took him three tentative plunger retractions on the syringe before he began drawing blood. On the plus side, he never once gave up on finding the artery, so she didn’t have to go through any more needle sticks.

Today, we got the results back from the doctor’s office. 100ug/dl. The normal range is given as 70-110ug/dl. So it would appear that everything is fine and hunky-dory, right? I’m still a bit concerned, to tell you the truth, and I’d kind of like some more reassurance.

See, back when kaylasmom was first diagnosed with diabetes, I read a lot of magazine articles. One of the articles, as I recall, suggested that the accuracy of glucometer readings can be thrown off by stressful situations. Or possibly that the accuracy of a blood pressure reading could be compromised if a patient had just had a needle stick to test for glucose. This is the kind of confusion I face because I don’t clip magazine articles and adequately archive them.

Anyway, when Michaela’s sample was obtained, she had just undergone one high-adrenaline episode, and was in the process of undergoing another one. Is there any reason to be concerned that the lab result might be artificially lower than her actual fasting glucose was?

2

If there would be any variation from the stress you describe, it would elevate the result. Catecholamines, such as epinephrine and cortisol are released into the blood stream in stressful situations. They prepare the body for action, that “fight or flight” feeling. They do so by sending more blood to the muscles of the exrtemities as well as stimulating the liver to produce increased levels of glycogen. That causes a slight increase in blood sugar. In an individual with normal pancreatic function, the rise would usually remain within the normal range.
A fasting value of 100 is in the high range of normal.
Was the testing done in a pediatric facility? If not, you may want to see if any further draws could be done by a peds specialist, whether phlebotomist, nurse or RT, depending upon the local standard of care. We often have tricks that an adult phlebotomist might not.
Good luck to you both.
M

3

Thanks for the response, picnurse. The blood draw was performed at one of the local hospitals here in Anaheim, CA, not specifically pediatric at all. I would have preferred the result be closer to 90 than 100 (middle of the target range, natch), but it’s good to know that any inaccuracies are likely to mitigate in her favor, when corrected for.