Change in CAP GH2 HbA1c Survey Grading
The College of American Pathologists began using accuracy grading based on target values set by the NGSP starting with the 2007A survey. In 2007 the acceptable limit was +/-15% of the target value; this limit was lowered to +/-12% in 2008, +/-10%in 2009, +/-8% in 2010 and +/-7% in 2011. The schedule for future reductions is:
New NGSP Certification Criteria
Beginning in September 2012 37 of 40 results need to be within +/- 7% (relative) of the SRL result (38 out of 40 for Level I laboratories) for a method to pass certification. The 40 samples are to be analyzed in singleton by the manufacturer/laboratory; the results will be compared to the mean of duplicate SRL results.
2010 Consensus Statement on the Worldwide Standardization of HbA1c
The American Diabetes Association, the European Association for the Study of Diabetes, the International Diabetes Federation, the International Federation of Clinical Chemistry and the International Society for Pediatric and Adolescent Diabetes recently published an updated consensus statement regarding HbA1c standardization (the original consensus statement was issued in 2007). The recommendations are:
- HbA1c test results should be standardised worldwide, including the reference system and results reporting.
- The IFCC reference system for HbA1c represents the only valid anchor to implement standardisation of the measurement.
- HbA1c results are to be reported by clinical laboratories worldwide in SI (Système International) units (mmol/mol – no decimals) and derived NGSP units (% - one decimal), using the IFCC-NGSP master equation (DCCT units).
- HbA1c conversion tables including both SI (IFCC) and NGSP units should be easily accessible to the diabetes community.
- Editors of journals and other printed material are strongly recommended to require that submitted manuscripts report HbA1c in both SI (IFCC) and NGSP/DCCT units.
- The reportable term for glycated hemoglobin is HbA1c, although other abbreviations may be used in guidelines and educational material (A1C).
- The above consensus recommendations apply through 2011, when they will be discussed again at the next consensus meeting at the IDF meeting in Dubai December 2011.
HbA1c Recommended for Diagnosis
An international expert committee that includes representatives from the American Diabetes Association (ADA), International Diabetes Federation (IDF), and European Association for the Study of Diabetes (EASD) has officially endorsed the use of HbA1c to diagnose diabetes. The recommended cutoff is HbA1c ≥ 6.5%. The recommendation has been officially endorsed by the American Diabetes Association and endorsed with qualifications by the American Association of Clinical Endocrinologists/American College of Endocrinologists, the Endocrine Society. the World Health Organization and the International Diabetes Federation.