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Changing Values
• When does 6.5 = 48?
Is this a well controlled diabetic?
Date HbA1c mmol/mol
23/04/2011 45
01/11/2010 48
12/01/2010 55
15/11/2009 65
01/09/2009 70
03/07/2009 86
03/05/2005 75
Before 2009
• HbA1C results would have appeared as:
Haemoglobin A1c 7.0% total Hb (3.6-6.8)
The HbA1c is expressed as a percentage of the Total Haemoblobin relative to a calibrator aligned to the DCCT method
After June 2009
• HbA1c results have appeared as:
Haemoglobin A1c 7.0% total Hb (3.6-6.8)
HbA1c (IFCC) 53 mmol/mol
The second result has been obtained using the IFCC reference standard
From June 2011
• HbA1c results will appear as:
HbA1c (IFCC) 53 mmol/mol (<48)
Relationship between old and new units
• IFCC-HbA1c (mmol/mol) = [DCCT-HbA1c (%) – 2.5] x 10.929
International Federation of Clinical Chemistry
Diabetes Control and Complications Trial
Following agreement between the various professions a series
of leaflets were produced outlining the changes.
Standardisation of HbA1c Assays.
HbA1c measured by ion-exchange chromatography as the glucose changes the charge on the haemoglobin molecule.
Originally calculated as a percentage of the HBA peak.
After the DCCT trial and the importance of meeting a set target was established a standardised approach was used to align methods to the DCCT method.
Not a true standard, so a reference standard was produced and a method assigned by isotope dilution mass spectrometry. Enables to report values in molar terms.
• www.diabetes.org.uk/Guide-to-diabetes/Monitoring/Blood_glucose/Glycated_haemoglobin_HbA1c_and_fructosamine/
• Calculator to convert from old to new units and links to leaflets one of which is for patients.
Diagnosis of Diabetes• Based exclusively on fasting glucose and
oral Glucose Tolerance Test.
• March 2011 WHO issued a report with the following recommendation
6.5% = 48 mmol/L
“Use of Glycated Haemoglobin
(HbA1c) in the Diagnosis of Diabetes
Mellitus
Abbreviated Report of a WHO Consultation
March 2011”
Available on the WHO Diabetes website
Answer
• When does 6.5 = 48?• When they refer to HbA1c measurements• An HbA1c of 6.5% = HbA1c of 48 mmol/mol.
Is this a well controlled diabetic?
Date HbA1c mmol/mol
HbA1C
%
23/04/2011 45 6.6
01/11/2010 48 6.9
12/01/2010 55 7.5
15/11/2009 65 8.4
01/09/2009 70 8.9
03/07/2009 86 10.4
03/05/2005 75 9.4