A hemoglobin A1c (HbA1c) test measures the amount of blood sugar (glucose) attached to hemoglobin. Hemoglobin is the part of your red blood cells that carries oxygen from your lungs to the rest of your body. An HbA1c test shows what the average amount of glucose attached to hemoglobin has been over the past three months. It’s a three-month average because that’s typically how long a red blood cell lives.

Also Known As: A1c, HbA1c, Glycohemoglobin, Glycated Hemoglobin, Glycosylated Hemoglobin
Test Panel: BSL, BSR, BSF, Blood Glucose Level, Fasting Blood Sugar, GTT, GCT
The hemoglobin A1c test tells you your average level of blood sugar over the past 2 to 3 months.
Why Get Tested?
- This test is used to monitor diabetes control.
- This test tells us the patient average glucose index over a long period of time (2 to 3 months).
- It tracks glucose in the milder form of diabetes.
- It helps to determine which type of drugs may be needed.
- Its measurement is of value in a specific group of patients like:
- Diabetic children
- Diabetic patients whose renal threshold for glucose is abnormal.
- Unstable diabetes type I, taking insulin.
- Type II diabetic women who become pregnant.
- Patients with changing dietary or other habits.
When To Get Tested?
- As part of a health checkup or when you have risk factors for or symptoms of diabetes.
- After first diagnosis with diabetes.
- Every 3-4 months or about 120 days to ensure that your glycemic goals are met and/or maintained.
- When your therapy plan has changed.
Sample Required?
- The blood sample is taken in the EDTA 3 to 4 ml.
- Washed RBC or hemolysate is prepared and this is stable for 4 to7 days at 4 °C.
- A blood sample can be drawn at any time.
Test Preparation Needed?
No Need Any Preparation for this test.
Normal Value
- HbA1 c (% of total Hb) = 4.0 to 5.2
- Hb A1 (% of total Hb) = 5.0 to 7.5
Mean Plasma Glucose:
This is mathematical calculations where Glycated Hb can be correlated with daily mean plasma glucose level (MPG).
The formula is as follows :
Mean Plasma Glucose = (35.5 X HbA1c) – 77.3
The Following table gives the recommendation for the treatment:
HbA1c level | mg/dL | mmol/L | Interpretation |
---|---|---|---|
4% | 65 | non-diabetic | |
5% | 100 | non-diabetic | |
6 % | 135 | 7.5 | non-diabetic |
7 % | 170 | 9.5 | ADA target |
8 % | 205 | 11.5 | treatment needed |
9 % | 240 | 13.5 | treatment needed |
10 % | 275 | 15.5 | treatment needed |
11 % | 269 | treatment needed | |
12 % | 298 | treatment needed | |
13 % | 326 | treatment needed | |
14 % | 355 | treatment needed |
HbA1c And Estimated Blood Glucose Level:
HbA1c level | Glucose level mg/dL |
---|---|
6% | 126 |
7% | 154 |
8% | 185 |
9% | 212 |
10% | 240 |
11% | 270 |
12% | 300 |
The HbA1c Increased Level Is Seen In:
- Newly diagnosed diabetic patient.
- Uncontrolled diabetic patient.
- Nondiabetic hyperglycemia is seen in:
- Cushing’s syndrome.
- Acromegaly.
- Corticosteroids therapy.
- Pheochromocytoma.
- Acute stress.
- Glucagonoma.
- Patient with splenectomy.
- Alcohol toxicity.
- Iron deficiency anemia.
- Lead toxicity.
The Decreased HbA1c Level Is Seen In:
- Hemolytic anemia.
- Chronic blood loss.
- Chronic renal failure.
- Pregnancy.
False Raised Level Of HbA1c May Be Seen In The Following Conditions:
- Renal failure.
- Raised level of triglycerides (hypertriglyceridemia).
- In Chronic Alcoholics.
HbA1c Can Be Controlled Or Lowered By:
- Exercise.
- Diet control.
- Medication.
- Or a combination of these.
The Significance Of HbA1c In Diabetic Patients:
- The incidence of retinopathy increases in patients with a HbA1c level between 6.0 to 7.0%
- Fewer chances for retinopathy when the HbA1c level is <6.5%.
- HbA1c level in diabetic patients recommended <7.0%.
- HbA1c should be checked at least twice a year.
- This is suggested that HbA1c level above 6.5% favor diabetes mellitus.
Diabetes type II risk can be lowered around in 58% of the cases by:
- Lowering the weight of around 7% of your body weight.
- Exercise like brisk walking for 30 minutes, 5 days a week.
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