Evaluation of Capillary Collection System for HbA1c Specimens

  1. Broatch Haig, BS, RD, CDE
  1. Park Nicollet Medical Center and the International Diabetes Center Minneapolis, Minnesota
  1. Address correspondence and reprint requests to Ellen M. Voss, BS, MT (ASCP), Park Nicollet Medical Center, Clinical Laboratory, 5000 West 39th Street, Minneapolis, MN 55416.

Abstract

Objective We evaluated the accuracy and stability of a capillary HbA1c collection system for use with a high-performance liquid chromatography analyzer.

Research Design and Methods The collection system requires that 5 ul blood is drawn into a calibrated capillary tube, which is then placed into a vial of stabilizing solution and sent for analysis. The study was conducted on simultaneously drawn capillary and venous blood specimens from 47 pediatric diabetes patients. Accuracy was determined by comparing the capillary to the venous HbA1c values. Stability was measured by analyzing 17 capillary specimens over 3 wk.

Results There was excellent agreement between the capillary and venous HbA1c values (capillary 0.959, venous +0.494, R2 = 98.7%). The capillary HbA1c values were 0.2% higher than the venous HbA1c values and decreased gradually over time (0.1% HbA1c/week) when stored at room temperature.

Conclusions The Bio-Rad (Richmond, CA) collection system is accurate, stable, and simple to use.

  • Received March 7, 1991.
  • Revision received November 13, 1991.
  • Accepted November 13, 1991.
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