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Glycated haemoglobin assays. Approaches to standardization of results
Author(s) -
Stott A.,
Casson I. F.,
Higgins G. J.
Publication year - 2001
Publication title -
diabetic medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.474
H-Index - 145
eISSN - 1464-5491
pISSN - 0742-3071
DOI - 10.1046/j.1464-5491.2001.00462.x
Subject(s) - medicine , glycated haemoglobin , standardization , quality assurance , glycated hemoglobin , surgery , diabetes mellitus , external quality assessment , endocrinology , type 2 diabetes , pathology , political science , law
SUMMARYAims To compare different approaches to DCCT standardization of glycated haemoglobin (HbA 1c ) results. Methods In the first part of the study seven laboratories in the Mersey area participated, using a variety of methods of measurement. The approaches used were the Standardization Initiative for Glycated Haemoglobin Scheme (SIGH) using fresh blood samples and the Wales External Quality Assurance Scheme (WEQAS) using both fresh and lyophilized blood samples. Additional studies performed in the Royal Liverpool University Hospital (RLUH) laboratory involved: (i) re‐calibration of the HPLC analyser using lyophilized blood samples supplied by the manufacturer and (ii) the use of fresh blood samples from the UK National External Quality Assurance Scheme (UKNEQAS). Results Inter‐laboratory analytical coefficients of variation following DCCT alignment showed little change. The effect on percentage bias was more marked and was independent of the level of HbA 1c . Comparing DCCT‐aligned HbA 1c results from 3902 diabetic patients attending the RLUH, indicated that there was a statistically significant difference ( P < 0.0001) between the corrected results produced by the five schemes. The effect of DCCT alignment on reported HbA 1c values using the different approaches was variable resulting in an apparent increase in the number of diabetic patients with poor glycaemic control (HbA 1c values > 7.0%) in all cases. Conclusion The method of HbA 1c standardization used determines the degree of correction required and a consensus approach is recommended. Implementation will assist extrapolation from research‐based evidence to local practice. Associated changes to patient management must come under the jurisdiction of the physicians responsible for the diabetic service.