Low result for a two-hour oral glucose tolerance test

August 15, 2007 10:43 PM

Low result for a two-hour oral glucose tolerance test. What does that mean?

I went in to see a doctor last week because I've been getting up to urinate several times a night. I'm 37, and I hadn't had a physical in over 2 years. He ordered a range of blood tests, and in order to rule out diabetes, he had me take a oral glucose tolerance test (OGTT). So 2 hours after I ingested a whopping dose of glucose, they drew my blood, and I got a reading of 50 mg/dl. Normal range according to the test results papers is 65-132 mg/dl. What does this mean? Am I hypoglycemic? I realize that there is a lot of debate about defining what exactly hypoglycemia is, and the only other things that showed up out of the norm on the blood tests is a slightly elevated triglycerides level 186 mg/dl.

The doctor recommended a diet higher in protein and lower in carbohydrates, but I do seem to be showing the symptoms of hypoglycemia over the past couple of years: confusion, irritability, depression, shakiness, sweating, blurred vision.

What should I do? Are there any further tests I should take? Would it be worth the money to invest in a glucose meter?

posted by AArtaud to health & fitness (9 comments total)

The Glucose page on Lab Tests Online is a start.
posted by euphorb at 12:11 AM on August 16, 2007

Apparently you want a four hour test to check for hypoglycemia, but it sounds like you have it from my non doctor perspective.
posted by BrotherCaine at 2:54 AM on August 16, 2007

You mentioned symptoms of hypoglycemia. I've had some trouble with this myself (although it never got to the point where I actually took the blood tests; my doctor, too, pointed me in the direction of diet.) For me, these symptoms came in very distinct episodes, and were very clearly linked to food: I'd have eaten something sugary, do some light exercise an hour later, and all of a sudden feel confused/shaky/sweaty and a panicked sense of Needing. Food. Now. I'd get myself to food, eat (like three bowls of cereal in a row), and a few minutes later it would all go away.

My point is that I wouldn't have not noticed these symptoms, or not connected them with food in my head. From your description, it sounds like maybe the symptoms you were having were more generalized, less acute -- if so, that has been different from my experience.

I do like your doctor's advice to eat more protein, though. I started eating Kashi "Go Lean" cereal in the mornings -- very high in protein, quite low in sugar -- and since then have had nary an episode. (Not to mention the stuff fills me up so well that I can totally forget to eat lunch if I'm not paying attention; not that skipping meals is good, but it's better than "whoops I'm getting dizzy have to eat -now-.")
posted by wyzewoman at 4:35 AM on August 16, 2007

It sounds like your doctor did not do a very good job explaining your lab results to you and skipped straight to the recommendations. Even if if they were explained, it's really easy to forget/not get it when you're immediately post test (50 mg/dl is pretty bad feeling if you're not used to it) and might be worried. You should call him/her and make an appointment specifically to discuss what the results mean and what the diagnosis is. This page discusses what are some causes for a low result on an OGTT, but really your physician has the whole bundle of information.

If you think that your physician wouldn't do a very good job of explaining even if you went back and asked, get a new one.
posted by a robot made out of meat at 4:52 AM on August 16, 2007

I think he was surprised at my blood sugar level after the 2 hour test. He asked me if I had indeed drank the glucose so I don't think he has much experience with hypoglycemia, if this is indeed what it is.

Once I go back to school, I'm to have another checkup and then I'll ask to see a dietician.

The main problem is that the medical establishment doesn't seem to really care too much about non-diabetic hypoglycemia and a lot of the literature condemns the more "popular" book-length treatments of it.

Obviously, diet is huge, although I'll miss french fries. I was wondering if it was worth buying a glucose meter for times like this, when I feel a burning hunger even though I just ate (a salad with sliced turkey).

I suppose it's all trial and error for each individual.
posted by AArtaud at 3:40 PM on August 16, 2007

If you suspect that you have a glucose disregulation severe enough to send you into the shakes and dizziness you need to take it very seriously. It is not as far as you think from dizzy and fuzzy vision to passing out while you're driving and dying. This is a major mortality issue for people at risk of severe hypoglycemia. I used to work as a researcher for a major pharmaceutical company, and repeatedly in observations of ~hundred of people with severe hypoglycemia risk several would die in car accidents; it's a much higher risk than the general population.

I wouldn't ask for a dietitian; I'd ask for an endocrinologist. To know what's really going on, they'd give you another OGTT or IVGTT and take blood for insulin, cortisol, aldosterone, glucagon, gut peptides, etc. that might be throwing your glucose regulation off.

It's true; for about $50 or less you can get an ok glucose meter and just test yourself a couple times a day to see where you really are. Fingersticks hurt, just so you know.
posted by a robot made out of meat at 6:14 PM on August 16, 2007

I've been getting up to urinate several times a night.

I'm an internist. We need more data. My guess is that during the 2hr GTT, your sugar went high causing a surge of insulin release that then made it come down again. Two hours is maybe a little fast for that, but certainly possible. If you're overweight, it's more likely.

Excessive urination is a cardinal symptom of diabetes, as is excessive thirst. (Nocturnal urination is also a symptom of obstructive sleep apnea. If you're obese, you may have both.) Early in the course of type II diabetes, reactive hypoglycemia is common.

It's worth spending $50 to get a glucometer and find out. Glucometers are cheap (sometimes even free); the test strips are very expensive but you should only need 10 or 20 strips to figure this out decisively.
posted by neuron at 9:11 PM on August 16, 2007

Hey, two great responses. I'll talk to my doctor about seeing an endocrinologist.

Let's see, more data. I have been diagnosed with obstructive sleep apnea. It's extremely perceptive of you to recognize that since waking up drenched in sweat puzzled me and my doctors for several years until I had a sleep study done. I used a CPAP machine now.

I am overweight. I'm 5'10" and weigh 200 lbs.

Neuron, do you also recommend that I see an endocrinologist?

The thing about this is that it makes a lot of sense to me since I've had more and more trouble concentrating over the past couple of years, and I have a general low energy level, even when I exercise regularly.
posted by AArtaud at 9:36 AM on August 17, 2007

Neuron,
What would be the protocol for testing myself with a glucose meter to find out? When I'm having symptoms? Specific times after meals?

Thanks again.
posted by AArtaud at 9:43 AM on August 17, 2007