RAPID HBA(1C) TESTING IN A COMMUNITY SETTING

OBJECTIVE - To determine whether the DCA 2000 analyzer provides valid and reliable HbA(1c) results when used under field conditions and oper ated by nonmedical personnel. This study was part of a community diabe tes education program, the Native American Diabetes Project, in which HbA(1c) was measured as an indicator of average glycemic control. RESE ARCH DESIGN AND METHODS - Two study samples were taken, the first in t he spring of 1994 and the second in the spring of 1995. Seven communit y members in 1994 and six new community members in 1995 were trained o ver 2 days, using standard protocol, to operate the DCA 2000 HbA(1c) a nalyzer and to collect two capillary blood samples from participants i n the Native American Diabetes Project. Duplicate DCA 2000 HbA(1c) mea surements performed by the community workers were compared with measur ements from a highperformance liquid chromatography (HPLC) system. Val idity and reliability measures were calculated. RESULTS - Of the parti cipants, 43 were studied in 1994 and 14 in 1995. Comparison of the mea n DCA 2000 results with those of HPLC showed high validity, with the a bsolute relative difference between the mean DCA 2000 and the external reference of HPLC (\ mean DCA 2000 - HPLC \ /HPLC) as 4.0 and 2.0% fo r 1994 and 1995, respectively. The Pearson correlation coefficients (r ) between these two measures were 0.968 and 0.996 for 1994 and 1995, r espectively. While the 1994 data appeared to have less validity for va lues >10%, they included only one value with a 60-min warm-up of the D CA analyzer. The 1995 data, all collected after a 60-min warm-up, had good correlation throughout the range of values. The within-run reliab ility was excellent, with an intraclass correlation coefficient of rel iability of 0.959 and 0.975 for paired samples, for 1994 and 1995 resp ectively. 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 significa nt (P < 0.0001). CONCLUSIONS - The DCA 2000 gave valid and reliable Hb A(1c) results when operated in a community setting by nonmedical perso nnel. Extending the warm-up period of the device to 60 min slightly im proved the validity and reliability of the test.