HbA1c is used for diagnosis of diabetes and monitoring of glycaemic control in diagnosed patients. It should not be used for diagnosis of T1DM, diabetes in pregnancy.
Reference range: 

See Chemistry Reference Ranges Document at Automated Chemistry Laboratory at Guy's and St Thomas'          

mmol/mol Hb
Sample type and Volume required: 
EDTA purple top tube (a separate tube is required)
Call in advance: 
Turnaround time: 
2 days
Time limit for extra tests: 
HbA1c cannot be added in retrospect
Blood Sciences Department-Guy's And St Thomas' Hospital
St Thomas' Hospital
North Wing - 5th Floor
Westminster Bridge Road
London SE1 7EH
Contact: 020 7188 9247

Guy's Hospital
Southwark Wing - 4th Floor
Great Maze Pond
London SE1 9RT
Contact: 020 7188 4781
Automated Chemistry Laboratory at Guy's and St Thomas' Clinical Advisory Service
Monday – Friday, 09:00-17:00 h: 07738897061
Out of hours, weekends & bank holidays: find details on Rotawatch on Trust intranet GTi, or contact via GSTT switchboard.
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 29/12/2022