Hemoglobin A1c

Hgb A1c, glycated hemoglobin, HA1C , Antrim #17141, EPIC: LAB5858, SOFT: A1C

Specimen Collection Criteria

Collect: One Lavender-top EDTA tube or one Lavender-top EDTA Microtainer®. (Minimum Whole Blood: 1.0 mL)

Physician Office/Drawsite Specimen Preparation

Do not centrifuge. Store whole blood refrigerated (2-8°C or 36-46°F) prior to transport. (Minimum Whole Blood: 1.0 mL)

Preparation for Courier Transport

Transport: Whole blood, refrigerated (2-8°C or 36-46°F). (Minimum Whole Blood: 1.0 mL)

Rejection Criteria

  • Frozen specimens.
  • Moderate to grossly hemolyzed specimens.
  • Specimens not collected and processed as indicated.


Whole blood may be stored refrigerated (2o-8oC) for up to seven days.


Monday – Friday, 24 hours a day; Saturday and Sunday (day shift only).
Results are available in 3-5 business days.

Reference Range

4.0 - 5.6 % Hb A1c.

4.0-5.6% HbA1c


5.7-6.4% HbA1c


Greater than or equal to 6.5% HbA1c


Test Methodology

Royal Oak: High Performance Liquid Chromatography (HPLC).


Hemoglobin A1c values of 5.7-6.4 percent indicate an increased risk for developing diabetes mellitus. Hemoglobin A1c values greater than or equal to 6.5 percent are diagnostic of diabetes mellitus. In the absence of unequivocal hyperglycemia, results should be confirmed by repeat testing or fasting glucose measurement. Fasting blood glucose rather than hemoglobin A1c should be used to diagnose acute onset of type I diabetes mellitus.

Limitations and Interfering Substances:

Samples from patients with hemolytic anemias will exhibit decreased A1C values due to the shortened RBC life span.

Samples from patients known to have high alcohol consumption will interfere with the accurate analysis of Hb A1c.

Samples from patients with polycythemia iron deficiency or post-splenectomy may exhibit increased A1c values due to somewhat longer RBC life span.

In the unusual variant forms (SS, CC, SC), no HbA is present, and therefore no Hb A1c will be detected.

Clinical Utility

Hemoglobin A1c provides an index of the mean blood glucose concentration over the preceding 100-120 days. The level of Hb A1c is proportional to both the average glucose concentration and life span of the protein (hemoglobin) in the circulation or tissue. If a patient is known to have no hemoglobin A or acute or chronic hemolysis, Fructosamine (glycated plasma proteins) is useful to assess glycemic control.

CPT Code


Test Codes

Antrim #17141, EPIC: LAB5858, SOFT: A1C

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