A1c

The A1c is a 90 day average of blood sugars. 4.9 translates to an AVERAGE blood sugar less than 90 mg/dl. This means the patient could be having hypoglycemia events, which can be fatal.

Suggestions: patient may be checking blood sugar infrequently and/or at a time when real-time BS is normal. Patient may be on medication that drops the blood sugar to a below-normal range (this can be adjusted by MD). Patient may not be eating enough or may be overdoing exercise.

Thankfully there are now many meds for DM and the physician or NP should be able to determine the best therapy for this patient. The WRONG thing to do is self-medicate and hope for the best.

I did my senior practicum in diabetes and have studied and lived with it extensively.

A1c is not really an average, because most of the blood cells are not 90 days old. On a curve, most of them would fall into the 2 or 3 week old range. That it's commonly called an average is a pet peeve of mine.

It can also be scewed by having many hypos coupled with many hyperglycemic excursions - this can result in a fairly low A1c, but have been a very dangerous way to get there. Also, recent studies show that wide swings are more dangerous than high A1c.

Agreed. But when I am consulting with patients or nurses who just want "the bottom line" I do not try to give more info then they need. That is why I called it an average. It implies there are highs and lows. The important thing for Grammyj to know is that the healthcare provider needs to be consulted and asked "what does this mean to ME?"

I should have also said that I agree that a person with a 4.9 who is being treated with meds, especially insulin, is in pretty dangerous territory.

Just because a single test at a certain point in time reads a certain way, does not mean that one is ever getting a true picture of what is going on with the patient. The patient needs to be followed over time, and as stated, various testing factors need to be examined to rule out skewing factors. That is why diabetics should be followed closely by a practitioner that is well versed in this disease. A random test here and there is not necessarily accurate, just like a random blood pressure reading here and there, may not show the true course of a person's hypertension or that the person even suffers from hypertension.

To a certain extent, the A1c test does this. It measures the percentage of red blood cells which have become glycated (glucose attached d/t hyperglycemia). It gives you a pretty good idea of average blood sugar over the previous few weeks.

Although the ADA does not consider it to be diagnostic, tt takes several weeks to develop an A1c high enough to indicate diabetes - and that one single test is pretty indicative.

The A1c is an *average*. Statistically, averages are interesting animals, because an extreme score can pull an average in one direction or another. For example, let's say Patient A had BG that was 100, 100, and 100. That would yield an average of 100. (100+100+100=300, 300/3= 100.) Let's say Patient B had BG that was 45, 55, and 200. That would yield the same average. (45+55+200=300, 300/3=100).

Of course, the average is built somewhat differently, but basically, over a period of three months, if their blood glucose followed a pattern something like this, Patients A & B would have the same A1c. Patient B might think he was doing great, but Patient B has blood glucose that is wildly out of control. He is getting lows that statistically counteract the highs, but he's not in good shape. It's not good for him to be going hypo, to have these spikes, and to have such swings. But the A1c won't reveal that.

So if you are getting 150s after eating, but dropping back to 70, you can end up with an A1c around 5, which correlates with blood sugar averaging 101.

THis is information that I gleaned from a diabetic board and the same question.

Makes sense to me now.

Although, ac, I understand why one should be concerned with an A1c of 4.9 and a patient that takes meds...

I was curious as to why the A1c COULD be so low if a person was diagnosed with diabetes through fasting blood sugars.

Thanks for all your info though everyone!

No, it's really not an average.

The blood test measures the percentage of red blood cells which have glucose attached to them at that moment. That's it.

You might be interested in this link:

http://www.diabetes.org/type-1-diabetes/a1c-test.jsp

If you read carefully, the test is explained as being "like" an average, but it is not a real average. It's a blood test. It doesn't add up numbers and divide by the quantity of tests. That you can get from a glucometer.

I had a patient who had a GTT, and it was high indicating Diabetes. About 10 years earlier, was diagnosed with hypoglemia. The patient refused to take the actos that was ordered (after DX of Diabetes) because it made the patient feel 'bad'. Dizziness, tired, hungry, etc. So patient was unmedicated. Pt came in with hypoglycemia through ED, was given D50 x2, was given breakfast, and BG was still unstable 50-60's. Pt admitted with D10 continuous IV, was in for 3 days. Various tests were done checking for tumor on pancreas etc, nothing was ever found. Was taught diet for hypoglemia. I later heard pt was again diagnosed with DM. What do you make of this? Any ideas? It sure confuses me! Could this be weight related? The patient had weight fluctuations.

I had a patient who had a GTT, and it was high indicating Diabetes. About 10 years earlier, was diagnosed with hypoglemia. The patient refused to take the actos that was ordered (after DX of Diabetes) because it made the patient feel 'bad'. Dizziness, tired, hungry, etc. So patient was unmedicated. Pt came in with hypoglycemia through ED, was given D50 x2, was given breakfast, and BG was still unstable 50-60's. Pt admitted with D10 continuous IV, was in for 3 days. Various tests were done checking for tumor on pancreas etc, nothing was ever found. Was taught diet for hypoglemia. I later heard pt was again diagnosed with DM. What do you make of this? Any ideas? It sure confuses me! Could this be weight related? The patient had weight fluctuations.

It's a strange scenario but I have heard of it before. Sometimes patients have hypoglycemia preceding true DM. It seems like sometimes the pancreas/liver go a little nuts before giving out. I think it's pretty rare, though. What is the pt's HbA1c? Has he/she EVER had a high fasting bg?

Perhaps the patient with DM with an HbA1c of 4.9% was never diagnosed by high fasting glucose levels. The OGTT is more sensitive than the fasting plasma glucose. One of the diagnostic criteria for DM is a BG >200 2 hours after a glucose tolerance test. (This is confirmed by repeating the OGTT). This patient might have failed the OGTT and started on meds and diet/exercise to improve insulin sensitivity.

If the 2 hour result is 140-199, this is called IGT (impaired glucose tolerance) and is often treated with meds before overt diabetes is diagnosed. It is possible that a person could have IGT and mistakenly believe they have been diagnosed with DM. This sometimes happens when clinicians are not very careful in explaining test results to patients. The treatment may look almost the same as DM, but in fact be prescribed to prevent or slow the progression to DM. In this case, the blood glucose levels may remain mostly in range, thus the great looking HbA1c, but the potential exists for hyperglycemia if the diet isn't carefully watched.

HbA1c of 4.9% is roughly equivalent to an average glucose of 87mg/dL. Previous posts already explained well how this test isn't technically an average, and can be very misleading if made up of wide BG swings.

Sorry this is so long. Hope it helps.