Stratus CS cardiac troponin I method: performance characteristics including imprecision at low concentrations.
OBJECTIVE
Define performance characteristics of the Stratus CS cardiac troponin I (cTnI) assay in routine practice.


METHODS
Imprecision at low cTnI values was assessed according to NCCLS EP5-A. Linearity was assessed by regression analysis; the reference interval was determined in 345 healthy individuals. Minimum detectable concentration (MDC) was assessed with 20 replicates of zero calibrator, and method correlation and bias (n = 77) were by Passing-Bablok regression and Bland-Altman plot.


RESULTS
cTnI of 0.06 microg/l corresponded to the 10% CV; the 99th percentile of the reference population was 0.07 microg/l. Linearity extended from 0 to 50.0 microg/l and the MDC was 0.010 microg/l. The method comparison equation was Stratus CS = 1.00 (Dimension RxL)-0.02 microg/l with no bias.


CONCLUSIONS
The Stratus CS cTnI assay in routine practice has performance characteristics appropriate for clinical use, including good correlation to a central laboratory cTnI method and imprecision of a high sensitivity troponin method with a CV of <10% at the 99th percentile of the reference population.
Department of Pathology, University of Maryland School of Medicine, Baltimore, MD 21201, USA. rchristenson@umm.edu
Robert H
RH
Christenson
Denise R
DR
Cervelli
Roger S
RS
Bauer
Marilynn
M
Gordon
D002138:Calibration; D002624:Chemistry, Clinical / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D009206:Myocardium / Q000378:metabolism*; D012016:Reference Values; D012044:Regression Analysis; D019210:Troponin I / Q000032:analysis*
D019210:Troponin I