June 20, 2016
View Full PaperIncidence of Undetectable, Measurable, and Increased Cardiac Troponin I Concentrations Above the 99th Percentile Using a High-Sensitivity vs a Contemporary Assay in Patients Presenting to the Emergency Department
Key Result
The Abbott high-sensitivity cTnI assay yielded a similar proportion of patients with cTnI concentrations above the 99th percentile compared to a contemporary assay (26% vs 31%, P=0.09).
Study Design
Type
Observational (n=2,100)
Structured PICO
Does the use of a high-sensitivity cTnI assay compared to a contemporary assay change the proportion of undetectable, measurable, and increased cTnI concentrations in patients presenting to the emergency department?
P
Population
2,100 patients presenting to a US emergency department who had serial cardiac troponin I measurements ordered on clinical indication.
E
Exposure
Abbott high-sensitivity cTnI (hs-cTnI) assay (sex-specific 99th percentiles: female 16 ng/L, male 34 ng/L)
C
Comparator
Contemporary cTnI assay (Abbott Architect; 99th percentile: 0.030 μg/L [30 ng/L])
O
Outcome
Incidence of undetectable (below limit of detection), measurable (LoD to 99th percentile), and increased cardiac troponin I concentrations above the 99th percentilesurrogate
The use of a high-sensitivity cTnI assay in the emergency department provides more numeric (measurable) concentrations without significantly increasing the number of results above the 99th percentile compared to a contemporary assay.
Main Result
Absolute Event Rate: 26% vs 31%
p-value: p=0.09
Abstract
INTRODUCTION: We compared the incidence of undetectable below the limit of detection (LoD), measurable (LoD to 99th percentile), and increased cardiac troponin I (cTnI) concentrations above the 99th percentile between Abbott high-sensitivity cTnI (hs-cTnI) and contemporary cTnI assays in a US emergency department population. METHODS: Patients (n = 2100) presenting to the emergency department who had serial cTnI (0, 3, 6, 9 h) measurements ordered on clinical indication were enrolled. Contemporary cTnI Abbott Architect used clinically; 99th percentile: 0.030 μg/L (30 ng/L) and hs-cTnI Abbott investigational; sex-specific 99th percentiles: female (F) 16 ng/L, male (M) 34 ng/L assays simultaneously measured fresh EDTA plasma. RESULTS: The hs-cTnI assay measured fewer undetectable cTnI concentrations compared to the contemporary cTnI assay across baseline (F: 31% vs 47%, M: 22% vs 40%) and serial (F: 21% vs 46%; M: 19% vs 54%) measurements. Conversely, the proportion of measurable cTnI concentrations was higher using hs-cTnI compared to contemporary cTnI assay across both baseline (F: 46% vs 31%; M: 60% vs 33%) and serial (F: 48% vs 28%; M: 83% vs 40%) measurements. The overall proportion of patients with increased cTnI concentrations above the 99th percentile was not significantly different between the contemporary (31%) and hs-cTnI (26%) assays (P = 0.09). CONCLUSIONS: In patients presenting to the emergency department, the use of the Abbott hs-cTnI assay provides clinicians with more numeric cTnI concentrations. This occurs via a shift from results below the LoD to those between the LoD and the 99th percentile and does not increase in the number of cTnI concentrations above the 99th percentile.