Hemoglobin (Hb) A1c
Also known as: Glycated Hemoglobin, Hgb A1c
Use
This test is useful for evaluating the long-term control of blood glucose concentrations in patients with diabetes, diagnosing diabetes and identifying patients at increased risk for diabetes (prediabetes).
Special Instructions
Use a lavender-top (EDTA), green-top (lithium heparin), or gray-top (sodium fluoride) tube for specimen collection. Ensure the collected specimen is free of clots and label it correctly before shipment. Additional confirmatory or reflex tests may require more time, so it's essential to allow for potential delays in testing schedules.
Limitations
For diagnostic purposes, HbA1c values should be used with information from other diagnostic procedures and clinical evaluations. Shortened erythrocyte survival, as in cases of hemolytic anemia or other hemolytic diseases, can result in decreased HbA1c. Conditions like hemoglobin variants, assay interferences, ethnicity, age, and altered red blood cell turnover may require alternative glucose testing. Abnormal hemoglobins affecting red cell half-life or in vivo glycation rates may result in unexpected glycemic control levels. HbF does not contain the glycated β‑chain characterizing HbA1c, leading to potentially lower HbA1c values in specimens with high HbF content.
Methodology
Other
Biomarkers
LOINC Codes
- 4548-4
- 4548-4
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
4 mL
Minimum Volume
0.5 mL
Container
Lavender-top (EDTA) tube, green-top (lithium heparin) tube, or gray-top (sodium fluoride) tube
Collection Instructions
Usual precautions for venipuncture samples should be observed. Samples must be free of clots.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Clotted specimen
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |