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
HEMATOLOGY (SHRL, SHKL)
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
Methodology
High-performance Liquid Chromatography BioRad-D-100
SHRCH: Turbidimetric immunoinhibition
SHGM and SHPH: Turbidimetric inhibition IA
CPT
83036
CDM Code
Update in Process
Epic Test ID
1230100749
Interface Order Alias
10153
LOINC
Hgb A1c: 4548-4
Additional Information
Policy Tech Reference #6953, #6864, #8967
Reviewed Date
2/20/2020