Sources of variability in measurements of cardiac troponin T in a community-based sample: the atherosclerosis risk in communities study.
Author(s): Agarwal SK, Avery CL, Ballantyne CM, Catellier D, Nambi V, Saunders J, Sharrett AR, Coresh J, Heiss G, Hoogeveen RC
Publication: Clin Chem, 2011, Vol. 57, Page 891-7
PubMed ID: 21519038 PubMed Review Paper? No
Purpose of Paper
Conclusion of Paper
Studies
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Study Purpose
The purpose of this study was to determine the effects of intraindividual variability, repeated sampling, and frozen storage on plasma cTnT levels. Plasma was stored at -70 degrees C and shipped at weekly intervals, under unspecified conditions, to a central lab where it was stored at -70 degrees C for up to 8 years. In some cases multiple specimens were collected from a single venipuncture and handled individually, but in other cases the plasma was aliquoted at first analysis and then stored for less than 2 days prior to repeat analysis. Specimens from the same individual were acquired 4-8 weeks and 8 years after the initial specimen.
Summary of Findings:
Specimens taken from the same individual 4-8 weeks apart had a CV of 16.6%, but replicate specimens from the same venipuncture that were mailed and processed separately had a CV of 18.3%. In contrast, the intraindividual variability between specimens obtained (and stored) 8 years apart was 48.4%, and only a weak correlation of values was observed (r=0.36). In specimens collected and stored for 36 months, cTnT levels declined by an average of 0.36 ng/L during the first year. cTnT levels were approximately 3-fold higher in individuals with heart failure than those without. Repeated assaying of the same specimen 2 days later gave a CV of 2.1% in individuals with heart failure and 11.2% in those without.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Cardiovascular Disease
- Not specified
Platform:
Analyte Technology Platform Protein Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Storage duration 0-3 years
0 days
2 days
4-8 weeks
8 years
Biospecimen Acquisition Time of biospecimen collection Day 0
4-8 weeks later
8 years later
Preaquisition Diagnosis/ patient condition Heart failure
No heart failure