Pathology Handbook

Glycated haemoglobin (HbA1c)


Glycated haemoglobin

Clinical Indications

For the monitoring of glycaemic control in known diabetics

The test CANNOT be used to diagnose diabetes

During the life of the red cells (normally 120 days) haemoglobin undergoes a degree of non-enzymatic glycation; HbA1c levels therefore reflect glucose levels during this period

HbA1c levels are reduced in patients with increased red cell turnover (haemolytic anaemia, chronic inflammatory disease, such as RA) and do not reflect diabetic control in these patients

Some abnormal haemoglobins affect the measurement of HbA1c; in these patients the laboratory will advise using fructosamine to assess glycaemic control

Test Includes


Request Form 

Request on ICE


On request

Specific Criteria


Patient Preparation


Turnaround Time

Same day


Whole Blood in purple top (EDTA) tube


2 mL


Vacutainer purple top

Causes for Rejection 

Unlabelled or inadequately labelled sample

Repeat test sent after an inappropriately short interval

New information

The way in which HbA1c results are reported changed from June 2009, in line with international recommendations.

We will continue to dual report until 31st March 2012.

Click on the relevant links below to access further information:

HbA1C conversion table

Risk of complications chart

Leaflet for Healthcare professionals

Leaflet for patients

HbA1C information at the web site 

Reference Range 

Normal (non-diabetic) <5.5%
Excellent control 5.5 - 7.0%
Satisfactory control 7.0 - 8.0%
Sub-optimal control 8.0 - 9.0%
Poor control >9%