Hemoglobin A1C

Test Code

HA1C

Alias/See Also

Glycohemoglobin, Glycosylated Hemoglobin, Glycated Hemoglobin, HA1C, HbA1c,GHB, Glycohgb, HgbA1C, HGA1C

Preferred Specimen

1 mL whole blood (0.5 mL minimum)

Instructions

Deliver to the laboratory promptly.

Transport Container

EDTA (lavender/purple top).

Specimen Stability

Room temperature: 3 days, Refrigerated: 7 days, Frozen: not recommended

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Grossly hemolyzed and clotted specimens are unacceptable.

Limitations

"This method will measure any glycosylated hemoglobin variants. This includes HbS, HbG, HbH, Hb Wayne, HbC, HbE, etc. Other hemoglobinopathies may give incorrect results with this test. Individuals with elevated levels of HbF, usually found in infants and some pregnant women will not give accurate HbA1c results with this assay. These samples must be assayed by an alternate method. Various substances other than sugars can form aggregates with hemoglobin and potentially interfere with the assay causing false results. Examples include individuals with opiate addiction, lead poisoning, and alcoholism."

Reference Range

4.2 - 6.3%

Clinical Significance

"Measurements of percent hemoglobin A1c are effective in monitoring long term glucose control in individuals with diabetes mellitus. The degree of glycosylation (reported as percent HbA1c) is proportional to the average concentration of blood glucose over the circulating life span of hemoglobin in the red cell (approximately 120 days). Patients with improved glycemic control (i.e. lower HbA1c) showed significantly improved prognosis with respect to micro-vascular complications including neuropathy, retinopathy, and nephropathy. Elevated levels of HbA1c suggest the need for more aggressive treatment of glycemia. The American Diabetes Association recommends that a primary goal of therapy should be a HbA1c of < 7% and that physicians should reevaluate the treatment regimen in patients with HbA1c values consistently > 8%."

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.