Hemoglobin A1C

Hemoglobin A1C

Alternate Test Name

Glycohemoglobin
Glycosolated Hemoglobin
Glycated Hemoglobin

Epic Mnemonic
Sunquest Mnemonic

LAB90
HA1CB

Category

Chemistry

Methodology

Turbidimetric inhibition immunoassay (TINIA)

Test Performance Schedule

Sunday - Saturday

Result Availability

Within 24 hours

Container

Lavender top (EDTA) tube

Volume

Pref. Vol.: 5.0 mL whole blood
Min. Vol.: 0.5 mL whole blood

Collection Instructions

• Routine venipuncture
• Immediately after collection, gently invert tube 5-10 times

Transportation Instructions

• Do not centrifuge
• Refrigerate entire Lavender top tube of whole blood

Stability

• Room Temperature: 3 days
• Refrigerated: 5 days

Causes for Rejection

• Contains clots
• Hemolysis
• Lipemia

Remarks

Medicare Medical Necessity Policy

CPT Codes

83036

Effective/Revised

03/24/2017

Hemoglobin A1c (HbA1c) is one of the glycated hemoglobins, a subfraction formed by the attachment of various sugars to the Hemoglobin molecule. In the erythrocytes, the relative amount of adult hemoglobin (HbA) converted to stable HbA1c increases with the average concentration of glucose in the blood. The conversion to stable HbA1c is limited by the erythrocyte's life span of approximately 100 to 120 days. As a result, HbA1c reflects the average blood glucose level during the preceding 2 to 3 months.

HbA1c is thus suitable to monitor long-term blood glucose control in individuals with diabetes mellitus. Glucose levels closer to the time of the assay have a greater influence on the HbA1c level. The risk of diabetic complications, such as diabetic nephropathy and retinopathy, increases with poor metabolic control. In accordance with its function as an indicator for the mean blood glucose level, HbA1c predicts the development of diabetic complications in diabetes patients.

For routine clinical use, testing every 3 to 4 months is generally sufficient. In certain clinical situations, such as gestational diabetes, or after a major change in therapy, it may be useful to measure HbA1c in 2 to 4 week intervals.