Glycosylated hemoglobin
(HBA1C)

Sample type

Whole blood (Lavender-top (EDTA) tube)

Uses

1. Monitoring compliance and long-term blood glucose level control in patients with diabetes.

2. Index of diabetic control (direct relationship between poor control and development of complications).

3. Predicting development and progression of diabetic microvascular complications.

4. Possibly for diagnosis of diabetes mellitus. Usefulness is still to be determined.

Precautions

You don’t need any special preparations for an HbA1c test

Interfering factors

The level of HbA1c is affected by factors such as the Hb content of reticulocytes, the mean age of RBCs in the blood circulation and the Hb glycation rate .

Any cause of shortened erythrocyte survival will reduce exposure of erythrocytes to glucose with a consequent decrease in Hb A1c (%). Causes of shortened erythrocyte lifetime might be hemolytic anemia or other hemolytic diseases, homozygous sickle cell trait, pregnancy, or recent significant or chronic blood loss. Glycated Hb F (fetal hemoglobin) is not detected as it does not contain the glycated β chain that characterizes Hb A1c. Specimens containing high amounts of Hb F (>10%) may result in lower than expected Hb A1

Pre-analytical errors

Clotted specimen; gross hemolysis

The corrective action

The sample must be rejected and another sample be obtained.

Post-analytical errors

1. reports were sent to the incorrect patient

2. write the wrong name in the report or the wrong results.

The corrective action

1. communication with patient, apologising for the error, and providing him with the correct report

2. If the report is not delivered to the patient and this error is discovered, the correct result or the correct name must be written, but if the report is delivered to the patient, you must communicate with him, apologise to him, and tell him that an error has occurred and replace it with the correct report.

Reference Range

Normal: 4.1 – 5.6 %

Prediabetes: 5.7% - 6.5%

Diabetes: ≥6.5%