Proficiency testing of Hb A1c: A 4-year experience in Taiwan and the Asian Pacific region

Shu Chu Shiesh, Hsiao Mei Wiedmeyer, Jau Tsuen Kao, Samuel D. Vasikaran, Joseph B. Lopez

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5 Citations (Scopus)


BACKGROUND: The correlation between hemoglobin A1c (Hb A 1c) and risk for complications in diabetic patients heightens the need to measure Hb A1c with accuracy. We evaluated the current performance for measuring Hb A1c in the Asian and Pacific region by examining data submitted by laboratories participating in the Taiwan proficiency-testing program. METHODS: Five fresh-pooled blood samples were sent to participating laboratories twice each year. The results were evaluated against target values assigned by the National Glycohemoglobin Standardization Program network laboratories; a passing criterion of ±7% of the target value was used. Measurement uncertainty at Hb A1c concentrations of 7.0% and 8.0% were determined. RESULTS: A total of 276 laboratories from 11 countries took part in the Hb A1c survey. At the Hb A1c concentrations tested method-specific interlaboratory imprecision (CVs) were 1.1%-13.9% in 2005, 1.3%-10.1% in 2006, 1.2%-8.2% in 2007, and 1.1%-6.1% in 2008. Differences between target values and median values from the commonly used methods ranged from -0.24% to 0.22% Hb A1c in 2008. In 2005 83% of laboratories passed the survey, and in 2008 93% passed. At 7.0% Hb A 1c,measurement uncertainty was on average 0.49% Hb A1c. CONCLUSIONS: The use of accuracy-based proficiency testing with stringent quality criteria has improved the performance of Hb A1c testing in the Asian and Pacific laboratories during the 4 years of assessment.

Original languageEnglish
Pages (from-to)1876-1880
Number of pages5
JournalClinical Chemistry
Issue number10
Publication statusPublished - 2009 Oct 1

All Science Journal Classification (ASJC) codes

  • Clinical Biochemistry
  • Biochemistry, medical


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