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Test Code HBA1C Hemoglobin A1c

Specimen Type

Whole Blood


Lavender top (k2 EDTA)

Preferred Volume

4 mL



Turnaround Time

24 – 72 hrs

STAT Availability

Not Available

Test Usage

Useful in evaluating the long-term control of blood glucose concentrations in diabetic patients

Test Methodology

turbidometric inhibition immunoassay  (TINIA)

Additional Information

HbA1c levels above the established reference range are an indication of hyperglycemia during the preceding 2 to 3 months or longer.

The ADA recommends measurement of HbA1c (typically 3-4 times per year for type 1 and poorly controlled type 2 diabetic patients, and 2 times per year for well-controlled type 2 diabetic patients) to determine whether a patient’s metabolic control has remained continuously within the target range.


American Diabetes Association: Standards of medical care for patients with diabetes mellitus. Diabetes Care 2009 Jan;32:S1

CPT Code


Test Includes

quantitative determination of % hemoglobin A1c in whole blood

Critical Results


Test Limitations

The test is not intended for the diagnosis of diabetes mellitus or for judging day-to-day glucose control and should not be used to replace daily home testing of urine or blood glucose.

Any cause of shortened erythrocyte survival will reduce exposure of erythrocytes to glucose with a consequent decrease in mmol/mol HbA1c values (IFCC) and % HbA1c values (DCCT/NGSP), even though the time-averaged blood glucose level may be elevated. Causes of shortened erythrocyte lifetime might be hemolytic anemia or other hemolytic diseases, homozygous sickle cell trait, pregnancy, recent significant or chronic blood loss, etc. Caution should be used when interpreting the HbA1c results from patients with these conditions.

Reference Range

Normal: <5.7%

ADA Guidelines for Glycemic Control 
Diagnosing Prediabetes   < 5.7-6.4%  
Diagnosing Diabetes >6.5% 
Goat with Diabetes: <7.0%

*More or less stringent goals may be appropriate for individual patients

Coverage Information

CMS has established a national coverage policy (NCD) for Medicare for this test as of November 25, 2002. Please document medical necessity. For more details click this link:

Minimum Volume

2 mL

Fee Code



Glycosylated Hemoglobin, HbA1c