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Test Code LAB90 Hemoglobin A1c (Hgb A1c), Blood Level

Test Name Alias

A1c | Hgb A1c | 8179 | glycosylated hemoglobin

Ordering Instructions

Hemoglobin A1c (HbA1c) measurements are used for monitoring the long-term blood glucose control in diabetic patients, and as an aid in the diagnosis of diabetes, and in identifying patients who may be at risk for developing diabetes mellitus (prediabetes).

The American Diabetes Association (ADA) recommends measurement of HbA1c at least two times a year in patients who are meeting treatment goals (and who have stable glycemic control) and quarterly in patients whose therapy has changed or who are not meeting glycemic goals.

In conditions associated with increased red blood cell turnover, such as sickle cell disease, pregnancy (second and third trimesters), glucose-6-phosphate dehydrogenase deficiency, hemodialysis, recent blood loss or transfusion, or erythropoietin therapy, only plasma blood glucose criteria should be used to diagnose diabetes. A1C is less reliable than blood glucose measurement in other conditions such as the postpartum state, HIV treated with certain drugs, and iron deficient anemia.

For patients with hemoglobin variants without hemoglobin A or rare hemoglobin variants that show interference with this method suggest monitoring long term glycemic control with serum fructosamine, LAB782 (Mayo Test ID- FRUCT).

Ref: Classification and diagnosis of diabetes: Standards of medical care in diabetes-2020. Diabetes Care 2020;43:S14-S31.

Icons & Photos

Collection Instructions

Specimen Collection: Blood


Container(s): Lavender Top (EDTA) 3.0 mL

Preferred Volume to Collect: 3.0 mL

Minimum Volume to Collect: 1.0 mL

Neonate Volume to Collect: 0.5 mL

Capillary collect ok: Yes

Microtainer acceptable: Yes


Collection Instructions:

  • Gently invert 8 - 10 times after collection.


Processing Instructions (Laboratory, Outpatient or Off-site collection)

  • Processed Specimen: Whole Blood EDTA
  • Centrifuge/Spin: No
  • Aliquot: No
  • Transport Temperature: Refrigerated

Rejection Criteria

Specimens with large clot present.

Specimen Stability

Ambient: 24 hours

Refrigerate: 7 days

Laboratory Retention: 72 hours

Test Frequency

Available daily, usual TAT 1-3 days.

Reference Range

Normal: 4.1 – 5.6 %

Prediabetes: 5.7% - 6.5%

Diabetes: ≥6.5%


The reference ranges are applicable to adults. For pediatric patients please refer to published literature.

Performing Department

Chemistry (all other locations)

Performing Department Laboratory Location

Spectrum Health Regional Laboratory, Grand Rapids, MI
Spectrum Health Big Rapids Laboratory, Big Rapids, MI
Spectrum Health Reed City Laboratory, Reed City, MI
Spectrum Health Zeeland Laboratory, Zeeland, MI


High-performance Liquid Chromatography BioRad-D-100


SHRCH: Turbidimetric immunoinhibition

SHGM and SHPH: Turbidimetric inhibition IA





CDM Code

Update in Process

Epic Test ID


Interface Order Alias



Hgb A1c: 4548-4

Additional Information

Policy Tech Reference #6953, #6864, #8967

Reviewed Date