title: Validation and modification of dried blood spot-based glycosylated hemoglobin assay for the longitudinal aging study in India.
abstract: OBJECTIVE
  This study aims to validate a modified dried blood spot (DBS)-based glycosylated hemoglobin (HbA1c) assay protocol, after a pretest in India showed poor correlation between the original DBS-based protocol and venous results.
  
  
  METHODS
  The original protocol was tested on different chemistry analyzers and then simplified at the University of Washington (UW). A second pretest was conducted in India to validate the modified assay protocol, using 44 quality control specimens.
  
  
  RESULTS
  Data from UW indicated that, using the original protocol, the correlation coefficients between DBS and venous results were above 0.98 on both Bio-Rad and Olympus chemistry analyzers. The protocol worked equally well on filter paper, with or without pre-treatment, and when the recommended amount of blood spot material, or less, was used. A second pretest of the modified protocol confirmed that DBS-based levels from both Olympus and Roche chemistry analyzers were well correlated with DBS results from UW (correlation coefficients were above 0.96), as well as with venous values (correlation coefficients were above 0.94).
  
  
  CONCLUSIONS
  The DBS-based HbA1c values are highly correlated with venous results. The pre-treatment of filter paper does not appear to be necessary. The poor results from the first pretest are probably due to factors unrelated to the protocol, such as problems with the chemistry analyzer or assay reagents.
authors.affiliation: Division of Geriatric Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Peifeng
authors.initials: P
authors.lastname: Hu
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle, Washington.
authors.forename: Michael
authors.initials: M
authors.lastname: Edenfield
authors.affiliation: Department of Laboratory Medicine, University of Washington, Seattle, Washington.
authors.forename: Alan
authors.initials: A
authors.lastname: Potter
authors.affiliation: National AIDS Research Institute, Pune, India.
authors.forename: Varsha
authors.initials: V
authors.lastname: Kale
authors.affiliation: National AIDS Research Institute, Pune, India.
authors.forename: Arun
authors.initials: A
authors.lastname: Risbud
authors.affiliation: Science and Technology Policy Institute, Washington, District of Columbia.
authors.forename: Sharon
authors.initials: S
authors.lastname: Williams
authors.affiliation: Andrus Gerontology Center, University of Southern California, Los Angeles, California.|RAND Corporation, Los Angeles, California.
authors.forename: Jinkook
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Global Health and Population, Harvard School of Public Health, Harvard University, Cambridge, Massachusetts.
authors.forename: David E
authors.initials: DE
authors.lastname: Bloom
authors.affiliation: Andrus Gerontology Center, University of Southern California, Los Angeles, California.
authors.forename: Eileen
authors.initials: E
authors.lastname: Crimmins
authors.affiliation: Division of Geriatric Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Teresa
authors.initials: T
authors.lastname: Seeman
mesh_terms: D000375:Aging; D059788:Dried Blood Spot Testing / Q000379:methods*; D005374:Filtration; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007194:India; D008137:Longitudinal Studies
chemical_list: D006442:Glycated Hemoglobin