Abstract

Objective: To determine if fingerstick blood samples yield accurate troponin measurements compared to conventional venipuncture blood samples using the i-STAT POC device. Methods: This experimental study was performed in the ED of a quaternary care suburban medical center between June-August 2011. Fingerstick blood samples were obtained from consenting adult patients already receiving standard (venipuncture) POC troponin testing. The time between fingerstick and standard draws was minimized. cTnI assays were performed at the bedside using the i-STAT 1 (Abbott Point of Care). The results of the fingerstick test were then compared to the results of the conventional test. Results: 94 samples from 87 patients were analyzed by both fingerstick and standard ED POCT methods (see Table 1). Four resulted in cartridge error. Compared to “gold standard” ED POCT, fingerstick testing has a positive predictive value of 100%, negative predictive value of 96%, sensitivity of 79%, and specificity of 100%. No significant difference in cTnI level was found between the two methods, with a nonparametric intraclass correlation coefficient of 0.994 (95% CI 0.992-0.996, p-value < 0.001). Conclusions: Whole blood fingerstick cTnI testing using the i-STAT device is suitable for rapid evaluation of cTnI level in pre-hospital and ED settings. Still, results must be interpreted with caution if they are within a narrow territory of the cutoff for normal vs. elevated levels. Additional testing on a larger sample would be beneficial. The practicality and clinical benefit of using fingerstick cTnI testing in the EMS setting must still be assessed.