Dried Blood Spot Test for Glycated Hemoglobin Measurement in Pediatric Diabetes Care

Background

The dried blood spot (DBS) card is a novel collection method for measuring glycated hemoglobin (A1C) in individuals with diabetes mellitus. The potential benefits of DBS specimens compared with traditional phlebotomy include a reduction in required total blood volume, reduced procedural pain, and an ability for self-initiated collection. DBS cards for A1C measurement have been validated in the adult population, but there is a paucity of pediatric data.

Methods

The aim of this study was to validate the use of A1C measurement by DBS cards in comparison to venous A1C and to identify potential barriers to implementing this novel approach. Venous and DBS card A1C samples were collected simultaneously from 62 patients at their local laboratory and transported to the central provincial lab for analysis. Correlation analyses compared venous and DBS A1C with data rescaling performed to account for the DBS–venous interassay difference.

Results

Mean venous A1C was 7.49% and DBS A1C was 7.26%, with an interassay difference of 0.23%. Data showed a strong, positive correlation between A1C collection methods (r=0.86, p<0.001); this was further strengthened at lower A1C values (A1C <7.5%, r=0.87, p<0.0001). A stronger relationship emerged when the data were rescaled to account for the DBS–venous interassay difference (r=0.8935, p<0.0001).

Conclusions

Given the potential feasibility, practicality, accessibility, cost-effectiveness, and performance characteristics of the DBS A1C, especially at lower A1C values hovering around the diagnostic threshold for diabetes, this study provides supporting evidence for consideration of the use of DBS A1C testing in pediatric diabetes care.