Key Points
- Evaluate the commutability of two candidate reference materials and assess a calibration strategy to harmonize cardiac troponin I measurements across 15 commercial field methods.
- Evaluated two candidate reference materials (a human tissue-derived and a recombinant troponin complex) alongside six cardiac troponin I-positive human serum pools across 15 manufacturer field assays.
- Assessed commutability by comparing inter-assay numerical relationships between candidate reference materials and human serum pools.
- Harmonized assays by applying linear regression parameters relative to median serum pool values and calculated interassay coefficients of variation before and after adjustment.
- Commutability was confirmed in only 45% of field methods for the tissue-derived complex and 39% for the recombinant complex.
- Baseline interassay variability across the 15 field methods ranged from 82% to 97%, with a median coefficient of variation of 88%.
- Mathematical harmonization using serum pools reduced interassay variability to between 9.0% and 23%, achieving a median coefficient of variation of 15.5%.
Structured PICO
Can candidate reference materials or human serum pools improve the standardization and harmonization of cardiac troponin I assays?
PPopulation15 cTnI assays evaluated using 2 candidate reference materials (CIT complex from human heart tissue and recombinant technology) and 6 cTnI-positive human serum pools
IInterventionHarmonization of cTnI assays using regression parameters relative to the analytical system yielding values closest to the median for each serum pool
OOutcomeCommutability of candidate reference materials and interassay coefficient of variation (CV) before and after harmonizationsurrogate
While candidate reference materials showed low commutability, a simple harmonization strategy using human serum pools can reduce interassay variability of cardiac troponin I methods by more than 5-fold.