Biological Variation in HbA1c Predicts Risk of Retinopathy and Nephropathy in Type 1 Diabetes
Response to McCarter et al.
- Patrick J. Twomey, MD, MRCPATH1,
- Adie Viljoen2,
- Timothy M. Reynolds3 and
- Anthony S. Wierzbicki4
- 1Department of Clinical Biochemistry, The Ipswich Hospital, Ipswich, U.K
- 2Department of Clinical Biochemistry, Addenbrookes Hospital, Cambridge, U.K
- 3Department of Clinical Chemistry, Queen’s Hospital, Burton-on-Trent, U.K
- 4Department of Chemical Pathology, Guy’s and St. Thomas’ Hospital, London, U.K
- Address correspondence to Patrick J. Twomey, MD, MRCPath, The Ipswich Hospital, Department of Clinical Biochemistry, Heath Road, Ipswich, Suffolk IP4 5PD, U.K. E-mail: pattwomey{at}doctors.org.uk
We read the article by McCarter et al. (1) with interest. Technically, all nonanalytical variation, irrespective of its source, is biological variation. Thus, mean blood glucose (MBG)-associated changes are included in biological variation. It must also be stressed that all population regression equations have confidence limits that need to be taken into account when comparing values from individuals to the population study mean.
However, such …
