Evaluation of a Portable Carbon Monoxide Breath Analyzer for Red Blood Cell Lifespan Measurement to Assess Hemolysis

Abstract

Measurement of red blood cell lifespan (RBCS) serves as a fundamental and quantitative indicator for hemolysis assessment. This study aimed to evaluate the agreement between a novel, portable carbon monoxide breath analyzer (etCOlink-300) and an established reference device (RBCS-01A) for RBCS determination. The etCOlink-300 incorporates dual alveolar gas sampling modes—gas bag and sampling tube—to accommodate varied patient conditions. In a prospective, single-center, paired-design trial, 100 subjects (80 anemic patients and 20 healthy adults) underwent RBCS measurement using both etCOlink-300 modes and the reference device. Agreement was analyzed via Pearson correlation, intraclass correlation coefficient (ICC), and Bland-Altman plots. Results demonstrated strong correlations between the etCOlink-300 gas bag mode and the reference device (r= 0.976), the sampling tube mode and the reference (r= 0.969), and between the two etCOlink modes (r= 0.970) (all P < 0.01). High agreement was further supported by ICC values (>0.96) and Bland-Altman analysis, with >95% of data points within the 95% limits of agreement. Stratified analysis in hemolytic (RBCS <70 days) and non-hemolytic (RBCS ≥70 days) subgroups consistently revealed excellent agreement (all ICC >0.89). The etCOlink shows high clinical equivalence to the reference standard. Its compact design (5.5 kg) and dual sampling modes provide a versatile, point-of-care solution for RBCS measurement, particularly suitable for bedside testing and patients unable to perform traditional breath maneuvers.