Rapid HbA1c testing in a community setting.

Abstract

OBJECTIVE: To determine whether the DCA 2000 analyzer provides valid and reliable HbA1c results when used under field conditions and operated by nonmedical personnel. This study was part of a community diabetes education program, the Native American Diabetes Project, in which HbA1c was measured as an indicator of average glycemic control. RESEARCH DESIGN AND METHODS: Two study samples were taken, the first in the spring of 1994 and the second in the spring of 1995. Seven community members in 1994 and six new community members in 1995 were trained over 2 days, using standard protocol, to operate the DCA 2000 HbA1c analyzer and to collect two capillary blood samples from participants in the Native American Diabetes Project. Duplicate DCA 2000 HbA1c measurements performed by the community workers were compared with measurements from a high-performance liquid chromatography (HPLC) system. Validity and reliability measures were calculated. RESULTS: Of the participants, 43 were studied in 1994 and 14 in 1995. Comparison of the mean DCA 2000 results with those of HPLC showed high validity, with the absolute relative difference between the mean DCA 2000 and the external reference of HPLC (magnitude of mean DCA 2000-HPLC magnitude of /HPLC) as 4.0 and 2.0% for 1994 and 1995, respectively. The Pearson correlation coefficients (r) between these two measures were 0.968 and 0.996 for 1994 and 1995, respectively. While the 1994 data appeared to have less validity for values > 10%, they included only one value with a 60-min warm-up of the DCA analyzer. The 1995 data, all collected after a 60-min warm-up, had good correlation throughout the range of values. The within-run reliability was excellent, with an intraclass correlation coefficient of reliability of 0.959 and 0.975 for paired samples, for 1994 and 1995 respectively. The mean coefficient of variation for these paired measures was 3.0% in 1994 and 2.8% in 1995. Both validity and reliability were improved by changing the warm-up period of the DCA 2000 analyzer from 5 to 60 min. All correlation coefficients were statistically significant (P < 0.0001). CONCLUSIONS: The DCA 2000 gave valid and reliable HbA1c results when operated in a community setting by nonmedical personnel. Extending the warm-up period of the device to 60 min slightly improved the validity and reliability of the test.