Key result
Specimen recentrifugation significantly reduced troponin I concentrations (P<.01), with a median reduction of 10 ng/L (95% CI -37.5 to -10.0) in specimens close to the cut-off value.
Why the study?
Does specimen recentrifugation alter troponin I levels in plasma specimens with elevated cardiac troponin I?
Observational (n=189)
Does specimen recentrifugation alter troponin I levels in plasma specimens with elevated cardiac troponin I?
Specimen recentrifugation reduces troponin I concentrations in specimens with elevated levels, potentially leading to patient misclassification.
Answers are grounded in this paper and cite their sources.
Recentrifugation may artifactually lower troponin I near cutoffs; this Level 5 observation leaves open whether preanalytical protocols require revision.
OBJECTIVE: To compare troponin I levels in plasma before and after specimen recentrifugation. METHODS: Over a period of 24 consecutive days, we recentrifuged 189 plasma specimens in which the troponin I level was higher than the positivity cut off (60 ng/L) and then remeasured the troponin I. RESULTS: Two-tailed Wilcoxon matched-pairs test results identified a statistically significant difference between troponin I concentrations before and after recentrifugation (P <.01). For 94 specimens close to the cut-off value (below the 50th percentile among the overall sample of 189 specimens), Passing-Bablok regression analysis showed a median reduction of 10 ng/L (95% confidence interval, -37.5 ng/L - -10.0 ng/L) in the concentrations of troponin I after recentrifugation. CONCLUSION: Specimen recentrifugation is followed by a reduction in troponin I concentrations in specimens with elevated cardiac troponin I, posing a risk for misclassification of patients. Moreover, this practice gives rise to unnecessary prolongation of turnaround time.
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Canovi et al. (2015) conducted an observational in Elevated troponin I (n=189). Specimen recentrifugation vs. Before recentrifugation was evaluated on Troponin I concentration (Median reduction of 10 ng/L, 95% CI -37.5 - -10.0, p=<.01). Specimen recentrifugation significantly reduced troponin I concentrations (P<.01), with a median reduction of 10 ng/L (95% CI -37.5 to -10.0) in specimens close to the cut-off value.
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