September 4, 2009Clinical Chemistry
Short- and Long-Term Cardiac Troponin I Analyte Stability in Plasma and Serum from Healthy Volunteers by Use of an Ultrasensitive, Single-Molecule Counting Assay
Why the study?
Does room temperature storage affect the stability of low concentrations of cardiac troponin I measured by an ultrasensitive assay in healthy volunteers and ED patients?
Population
Healthy volunteers and emergency department patients presenting with chest pain and low cTnI concentrations.
Comparison
Room temperature storage of EDTA-plasma and… vs Immediate centrifugation and freezing at -80 °C.
Design
Other
Follow-up
up to 48 hours (in vitro storage)
Authors
Discussion
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Member takes
Implication
Low cTnI remains stable at room temperature; leaves open whether findings generalize to routine clinical workflows or alter troponin-based decisions.
Key Points
- To evaluate the in vitro stability of cardiac troponin I at low baseline concentrations in EDTA-plasma and serum stored at room temperature across short- and long-term intervals using an ultrasensitive assay.
- Collected EDTA-plasma and serum separator tube blood samples from 15 healthy volunteers, testing short-term room-temperature stability at 0, 2, 4, and 6 hours and long-term stability at 24 and 48 hours.
- Assessed stability at 1 and 6 hours in an additional 10 healthy subjects and 12 emergency department patients presenting with chest pain.
- Measured cardiac troponin I concentrations using the Erenna single-molecule counting immunoassay with a 0.2 ng/L limit of detection.
- Mean coefficient of variation was 11% (range 4%–24%) over 6 hours and 14% (range 2%–34%) over 48 hours across sample types.
- Average hourly concentration changes were minimal, showing 0.001 (SD 0.031) ng/L per hour during the 6-hour interval and 0.015 (SD 0.033) ng/L per hour over 48 hours.
- Percent changes were <1% at 1 hour in healthy subjects and <3% at 6 hours in chest pain patients, with stability unaffected by sample type (plasma vs. serum).
Structured PICO
Does room temperature storage affect the stability of low concentrations of cardiac troponin I measured by an ultrasensitive assay in healthy volunteers and ED patients?
P
Population
Healthy volunteers and emergency department patients presenting with chest pain and low cTnI concentrations.
I
Intervention
Room temperature storage of EDTA-plasma and serum samples for short-term (up to 6 hours) and long-term (up to 48 hours) intervals before centrifugation and freezing.
C
Comparator
Immediate centrifugation and freezing at -80 °C.
O
Outcome
In vitro stability of cTnI (measured by mean CV and change in concentration per hour).surrogate
Low concentrations of cardiac troponin I are stable in whole blood and serum at room temperature for up to 48 hours, validating the use of high-sensitivity assays for samples with delayed processing.
Cite This Study
Wu et al. (2009) studied this question.