Assay

Glycated Haemoglobin

Key Words

HbA1c

Specimen Collection

Blood (red EDTA)

Turnaround time

72hrs

Test indications

HbA1c is a measurement of the glycation of haemoglobin which occurs proportionally to both the average glucose concentration and the life span of the red blood cells in the circulation. The measurement of HbA1c has therefore been accepted as a monitoring tool for assessing blood glucose levels over the previous 120 days and is a vital tool in the clinical management for diabetes

Interferences

HbA1c result are not reported in the presence of a number of haemoglobin variants. Results can be  reported on patients with heterozygous HbS, HbC, HbD and HbE genotypes, however results on patients with haemoglobin variants are for monitoring only, and should not be used for diagnosis.  

If a haemoglobin variant is detected during testing, further investigations can be performed. An EDTA sample will need to be sent to the Haematology department for a Haemoglobinopathy screen (RTS).

HbA1c is dependent on both the mean blood glucose concentration and turnover of red blood cells. An increased RBC turnover affects HbA1c, and should be considered when interpreting results.

**Please note, this information pertains to the analysis performed by the laboratory only**

Reference Range

Non-diabetics: 20-42mmol/mol

HbA1c of >48mmol/mol is used as a cut-off for the diagnosis of Type II Diabetes Mellitus

Analytical error

1.6%

Reference change value

5.5%

Minimum retesting interval

Requests made within 7 days of a previous result on a patient are intervened