06.02 Hemoglobin A1c (HbA1C)
- Hemoglobin a1C
- Normal Value Range
- Special considerations
- Elevated values
- Decreased values
- Normal value
- After a prolonged exposure to glucose molecules, HGB binds to glucose
- RBC life is 90-120 days
- Blood test measures average amount of HGB bound to glucose
- Measured as a percentage
- Goals –
- <5% for non-diabetics
- 5.6-7.5% for diabetic patients
- Special considerations
- Lavender top tube
- Elevated A1C
- Poor controlled Diabetes
- Non-diabetic hyperglycemia
- Cushing’s disease
- Decreased A1C
- Renal failure
- Blood loss
- Hemolytic anemia
- Sickle Cell anemia
- Lab Values
- Glucose Metabolism
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In this lesson, we’re going to talk about something called the hemoglobin A1c
So the normal value of the hemoglobin A1c is going to be 5.6 to 7.5 percent. Now it’s a percentage and there’s a crazy calculation, but what the hemoglobin A1c is is basically it’s a snapshot of glucose control over about three months. So let’s get into the ins and outs of what it actually is.
So we have lots and lots of red blood cells, and they’re in our blood and they’re in our veins, and so is glucose. So what happens is, is that overtime glucose gets exposed to the hemoglobin molecules on the red blood cells, and they go to this process called glycation, where the glucose molecule attaches itself to the hemoglobin molecule. That because the red blood cells life span is about 90 to 120 days, what we do is the hemoglobin A1c and it measures the percentage of red blood cells that have the hemoglobin molecules attached.
So you can imagine, the more glucose that you actually have in your blood, the higher percentage of hemoglobin that’s going to become attached to it. So for someone who has poorly controlled glucose in diabetic control, they’re going to have higher percentages of hemoglobin A1c. Now we measure Hemoglobin A1c as a percentage, so it’s not uncommon to see that. For patients that have diabetes, we want them to be under the upper end of this range, so we want them to have less than a 7.6% hemoglobin A1c, or we commonly call in A1c. For normal patients, we expect them to be on the low end or lower.
When you’re submitting these blood samples to the lab, just remember that we’re going to use the purple top or the labrador talked to, and it’s got the EDTA in it, which is the anti clotting additive to keep blood clots from forming. We want those red blood cells to flow freely, so that we can get accurate measurements which is why we use this particular too. The hemoglobin A1c is also used for pre-diabetics, so that we can predict if they may potentially have glucose control issues in the future. Also remember that it’s a three-month average because the red blood cell was for 90 to 120 days.
When we have abnormal values when do we expect are patients that have elevated hemoglobin A1c levels? Well the first condition is going to be poorly controlled diabetic patients. Because their glucose levels are particularly high for longer periods of time, you can expect your hemoglobin A1c to be high. The other time you’re going to have it is with non diabetic hypoglycemic patient. The reason you’re going to have it is because there’s some sort of problem with the patients insulin. So look at causes for insulin resistance, IE steroids. So stress increases system and cortisol levels, Cushing’s Disease increases overall cortisol levels, increase steroid use, so your corticosteroids. That’s going to cause an insulin resistance. There’s another condition called pheochromocytoma where you have a tumor on the adrenal gland and that over produces the amount of cortisol patient has.
You’re not typically going to have decreased hemoglobin A1c levels, but you will in a couple of certain instances. And if you see low values, anticipate some sort of problem with the red blood cells. Remember the hemoglobin is attached to the red blood cells, and we’re looking at the amount of glucose attached to this hemoglobin molecules. So if you don’t have red blood cells, you’re not going to be able to measure the hemoglobin, and you’re not going to be able to measure that glycated or attached glucose molecules that are attached to those hemoglobin. So look for things like renal failure, because you’re going to have a decrease of erythropoietin, and things like blood loss or anemia.
In this lesson, we really focus on the nursing concept of lab values and glucose monitoring, because we want to pay attention to our patients overall glucose control.
Okay, so let’s recap.
The normal value for hemoglobin A1c is 5.6 to 7.5%.
Remember that it’s a three-month average looking for glucose control in those patients that are going to have elevated glucose levels. So this is going to be your diabetics or your non-diabetic patients that have high blood glucose.
Ideal A1c is going to be under the 7.5% for those diabetic patients.
Your elevated hemoglobin A1c are going to be an indication of poor glucose control, and your decreased hemoglobin A1c are going to be indicative of some sort of loss of those red blood cells.
That’s it for our lesson on hemoglobin a1c. .Make sure you check out all the resources attached to this lesson. Now, go out and be your best selves today. And, as always, happy nursing!!