Analytical performance of Abbott C-16000 analyser haemolysis index and its potential use in measuring plasma cell-free haemoglobin.

Purpose: Measurement of the haemolysis index (HI) is usually performed in clinical chemistry laboratories in order to inform about whether biological analyses are influenced by in vivo or in vitro haemolysis of the specimen. Our aim was to evaluate the analytical performance of Abbott C-16000 analyser HI measurement in order to determine whether this could be used to reliably measure cell-free haemoglobin (fHB) in plasma samples. Methods: The repeatability, reproducibility, lower limit of detection (LLOD) and lower limit of quantification (LLOQ) of C-16000 HI measurement were determined as well as the potential interference of bilirubin, triglycerides and myoglobin. C-16000 HI values of biological samples with various ranges of fHB were compared to those measured using the established reference method, second-derivate spectroscopy. Results: Results: C-16000 HI determination showed excellent linear correlation with the reference method (y = 1.0043x ­ 1.248, R² = 0.998), a broad analytical measurement range (400-20,000 mg/L; y = 0.9904x + 72.972, R² = 0.999), clinically relevant LLOD (56 mg/L) and LLOQ (84 mg/L), good repeatability (coefficient of variation (CV) = 1-15%) and good reproducibility (CV = 5-7%). No interference was observed with myoglobin at concentrations as high as 35,447 mg/L, unconjugated and conjugated bilirubin (at concentrations up to 500 mg/L and 375 mg/L, respectively) or triglycerides up to 6.8 mmol/L. However, a significant underestimation of fHB concentrations was observed at higher triglyceride levels. Conclusion: This study demonstrates that Abbott C-16000 analyser HI is reliable and accurately measures plasma fHB concentrations under pathophysiological conditions except when there are high blood concentrations of triglycerides.

Multisystem inflammatory syndrome in children: Inputs of BNP, NT-proBNP and Galectin-3.

BACKGROUND: Since the COVID-19 pandemic began, a cohort of Multisystem inflammatory syndrome in children (MIS-C) patients has been described. Cardiac involvement is found in 80-85% patients, typically with cardiac dysfunction with or without cardiogenic shock. Here, three cardiac biomarkers, BNP, NT-proBNP and Galectin-3 were compared for the first time in MIS-C in a unique cohort of hospitalized French children. METHODS: Fourteen children with MIS-C hospitalized at Necker-Enfants Malades for cardiac management during the first three COVID-19 waves (March 2020-March 2021) were included. All had positive SARS-CoV-2 serology and proven cardiac involvement assessed by transthoracic echocardiography. NT-proBNP, BNP and Galectin-3 were measured at admission, discharge and first follow-up clinic. RESULTS: All admission Galectin-3 measurements were comprised within the reference interval, both in patients with and without cardiogenic shock, and did not vary between admission, discharge and first follow-up clinic. Both median admission BNP and NT-proBNP were higher in children with cardiogenic shock than without. Median admission NT-proBNP was higher than its predictive positive value in heart failure in both groups of children, while median BNP was below its negative predictive value in children without cardiogenic shock but with cardiac dysfunction. CONCLUSIONS: Galectin-3 does not seem affected by MIS-C. NT-proBNP seems to increase more precociously than BNP possibly making it a more sensitive marker for screening of heart failure in MIS-C.