Comparative Study of HbA1c Measurement Using Immunoturbidity and High Performance Liquid Chromatography Techniques in Faculty of Medicine Vajira Hospital, Navamindradhiraj University.

Abstract

Objectives: To compare HbA1c measurement methods by Immunoturbidity from Cobas Integra

800 Analyzer and High Performance Liquid Chromatography (HPLC) from ADAMS A1C HA

8180V Analyzer.

Methods: This is a cross-sectional analytic study comparing two HbA1c measurement methods in

the same samples. One hundred and sixty EDTA whole blood sample were determined for

HbA1c by Immunoturbidity from Cobas Integra 800 Analyzer and High Performance Liquid

Chromatography (HPLC) from ADAMS A1C HA8180V Analyzer. The data from two methods

were separated from concentration of HbA1c: level 1 normal range HbA1c 4-6.4%, level 2

diagnose diabetes range HbA1c 6.5-8% and level 3 range HbA1c over 8 %. The data from

three levels of two methods were compared and analyzed for statistical correlation.

Results: Data from three levels of two methods were statistical calculated. The correlation studies

of three levels showed good correlation. The correlation coefficient(r) were 0.941, 0.923 and

0.989 and linear regression equation were y=1.066x-0.451, y=0.982x+0.219 and y=1.024x-

0.017, respectively. A strong correlation was also observed. The coefficient of variation (% cv)

in within run were SD=0.05, %CV=0.78 and SD=0.05, %CV=0.79 and between-run were SD=

0.08, 0.16 %CV=1.47, 1.58 and SD=0.10, 0.13 %CV=1.78, 1.58, respectively. Data from two

methods showed good correlation (coefficient of variation, %CV<2%). Bland and Altman plot

was used to calculate mean difference (bias) and agreement between two methods. The

plot showed the presence of good agreement between two methods and three levels, data

of values were lying within the mean + 1.96SD

Conclusion: Statistical analysis showed that Immunoturbidity from Cobas Integra 800 Analyzer and

High Performance Liquid Chromatography (HPLC) from ADAMS A1C HA8180V Analyzer were

strongly correlated and congruent results in three level concentrations.

Keywords: HbA1c, immunoturbidity, HPLC