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YSI Blood Glucose Analyzer, Model 23A

  • ca. 1975
  • Manufactured by Yellow Springs Instrument Company
    Made in Yellow Springs, Ohio
  • 16.25 in. D x 13 in. W x 8.375 in. D
    Painted metal, aluminum, plastic, rubber
  • On display in Making Modernity
  • Gift of Dr. Leland Clark
  • 2004.018


This model was the first whole-blood glucose analyzer. The instrument directly measures the whole-blood glucose level from a 25-microliter sample within a ±2% accuracy. The sensor created for the Model 23A was the first commercial biosensor and was used in the Miles Biostator, the first artificial pancreas. The U.S. Food and Drug Administration has identified the YSI Model 23A and subsequent designs as the reference standard for measuring glucose.

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Arnold O. Beckman

CHF’s Beckman Center for the History of Chemistry was started with a generous grant from the Arnold and Mabel Beckman Foundation in 1987.



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