Comparison of emergency department patient classification by point-of-care and central laboratory methods for cardiac troponin I.
For patients admitted to the emergency department (ED) with suspected acute coronary syndrome, we compared results of a rapid, point-of-care whole blood assay for cardiac troponin I (Abbott i-STAT, Abbott Point-of-Care, East Windsor, NJ) (Tn-P) with an automated central laboratory plasma assay (Siemens TnI-Ultra, Siemens Medical Solutions Diagnostics, Tarrytown, NY) (Tn-U). Clinical data were obtained during a 6-month period during which ED patients were screened by Tn-P, with retesting of elevated results by Tn-U. Of 5,909 Tn-P results, 573 (9.7%) were elevated; these and a random selection of 137 negative specimens were retested by Tn-U. Of the specimens with elevated results, 4.5% retested negative by Tn-U, even though Tn-U typically gave about 50% higher results and had a lower manufacturer-specified 99th percentile cutoff. Of the negatives, 5.8% retested as elevated by Tn-U, but with levels no higher than 0.1 ng/mL (0.1 microg/L). Rapid whole blood testing for cardiac troponin I gave generally reliable patient classifications compared with plasma testing in the central laboratory, but besides missing small elevations, produced some apparent false-positives.
Bock
Jay L
JL
Department of Pathology, Stony Brook University, Stony Brook, NY 11794-7300, USA.
Singer
Adam J
AJ
Thode
Henry C
HC
D054058:Acute Coronary Syndrome / Q000097:blood* / Q000145:classification*; D004636:Emergency Service, Hospital; D006403:Hematologic Tests / Q000379:methods; D006801:Humans; D007755:Laboratories, Hospital; D019095:Point-of-Care Systems; D011237:Predictive Value of Tests; D019210:Troponin I / Q000097:blood*
D019210:Troponin I