What Does a Glucose Value of 3.4 Mean?

by William Quick, M.D. Health Professional

I just saw the following question:

If my glucose test is 3.4, what does this mean? I had tested in the past several times and it came back 5.6, 6.6, and 5.4 but never so low as 3.4. I am 59 years and not a diet person.

My reply:

As you know, your blood glucose (BG) values are in mmol/L (the measurement system used throughout most of the world) rather than the measurement system used in the United States (which are in mg/dl). Don't ask me why we in the US are so stubborn about units of measurement, but we also use miles instead of kilometers and pounds instead of kilograms. To convert the BG, you can multiply the value in mmol/L by 18 to get the value in mg/dl -- or use an online BG converter such as the one at Blood Sugar Converter.

I'll assume that you don't have already have a diagnosis of diabetes.

If you were fasting at the time of the test, a blood glucose value of 3.4 mmol/L (62 mg/dl) is a bit on the low side but probably okay; normal ranges for people who haven't eaten recently are below 100 mg/dl (5.6 mmol/L). See
How to Tell if You Have Diabetes or Prediabetes
for further information about what's usually considered "normal."

If your physician was looking for the possibility of diabetes (a high sugar problem), then a value of 3.4 is certainly not a problem; on the other hand, if your physician had been looking to see if you have hypoglycemia (low sugar) then this value is suspicious, but not diagnostic.

Hypoglycemia frequently has symptoms such as shakiness, hunger, headache, or rapid heart rate. If you had such symptoms when your BG was measured, you might want to adjust your meal plan to decrease the chances of more severe hypos. The usual recommendation to avoid low sugar symptoms would be to eat small frequent high protein meals - discuss whether to try this dietary change with your physician

Also, if you had exercised strenuously before the test
had not eaten recently, the value could have dropped simply as a result of exercise.

Sometimes, people who later develop diabetes may have hypoglycemia during the years before the sugar goes high, so there's a chance your BG of 3.4 might be an early warning that someday you'll go high. You mentioned that you had previously had a BG value of 6.6, which is in the pre-diabetes range, so continuing to check your BG regularly seems like a good idea. I'd especially recommend that if you are getting blood tests for other reasons, to be sure that your physician also orders a blood glucose level to be checked at the same time.

Hope this helps!

William Quick, M.D.
Meet Our Writer
William Quick, M.D.

Bill Quick, M.D., is a physician who lives with diabetes. He is the editor of www.D-is-for-Diabetes.com and a past president of the American Association of Diabetes Educators. Dr. Quick wrote about diabetes for HealthCentral.