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Test Code HbA1c Hemoglobin A1c

Additional Codes

Cerner

NextGen

Hemoglobin A1C

Hemoglobin A1C

A1c

 

HgbA1C

 

Alternate Name(s)

HgbA1C

HbA1c

A1c

Glycated Hemoglobin

Methodology

Immunoturbidometric, endpoint

Patient Preparation

None

Collection Instructions

Standard phlebotomy practices.

Specimen Requirements

Container
  • 12 x 75 mm tube EDTA-2K or EDTA-3K Lavender

 or 

  • Microtube EDTA-2K or EDTA-3K Lavender

Stability

Storage

Temperature

Stability

Room Temperature

18-28°C

≤ 3 days

Refrigerated

2-8°C

≤ 3 days

Rejection Criteria

Clotted Specimens

Specimens with a hemoglobin <6 gm/dL

Result Reporting and Reference Values

  • A1C%.

                Reported in %A1c

A1C%

Interpretation

<5.7%

Decreased risk of diabetes

5.7%- 6.4%

Increased risk for diabetes “Prediabetes”

>6.5%

Diagnostic of diabetes

<7.0 %

Glycemic recommendation of nonpregnant adults with diabetes
  • Estimated average glucose (eAG) is calculated and reported in mg/dL along with the A1C%.

Reflex Testing

None

Limitations

  • There is significant negative interference with fetal hemoglobin (HbF). HbA1c results are invalid for patients with abnormal amounts of HbF including those with known Hereditary Persistence of Fetal Hemoglobin.
  • Any cause of shortened red cell survival (hemolytic diseases, pregnancy, and significant red cell loss) will reduce exposure of red cells to glucose with a consequent decrease in %A1c values.

Useful For

HbA1c is the major species of glycohemoglobin found in human blood and is formed by the non-enzymatic glycation of the free amino group at the N-terminal of the hemoglobin A0 β-chain. The percentage of HbA1c (% A1c) is widely used as a retrospective index of glycemic control in diabetic patients. Studies have shown that glycemic control results in reduction in diabetic complications. The glycation of hemoglobin depends on both the lifespan of the red blood cell and the blood glucose concentration. Since the rate of glycated hemoglobin formation is directly proportional to the concentration of glucose in the blood, the level of glycated hemoglobin is an index of the blood glucose concentrations over an extended period of time (~6 to 8 weeks).