Analytical characteristics and performance of a new hs-cTnI method: a multicenter-study

Objectives: The present multicenter study was designed to evaluate the analytical performance and the 99th percentile value of the reference healthy population i.e., 99th percentile upper reference limit of the MAGLUMI^® CLIA high-sensitivity cardiac troponin I (hs-cTnI) method.

Methods: Analytical performances and the 99th percentile URL value of the chemi-luminescent-immuno-assay (CLIA) method were evaluated using validated and standardized experimental protocols. Two cohorts including healthy adult individuals were enrolled. The first one included 989 blood donor volunteers (489 women and 500 men) aged 18-70 years (mean age 43 years, interquartile range 31-54 years). The second population included 47 healthy individuals (31 women and 16 men, mean age 78 years, interquartile range 73-81 years) aged≥71 years.

Results: The distributions of hs-cTnI levels in both sexes are highly right-skewed, and men show significantly (p=0.0028) higher biomarker values than women. Moreover, in both sexes the hs-cTnI levels progressively increase after the 55 years. In the multivariate analysis (n=958), hs-cTnI was found to be significantly associated to NT-proBNP (p<0.0001), sex (p<0.0001) and BMI (p=0.0424). The 99th percentile URL values, calculated using the bootstrap method in the total reference heathy population (age≥18 years), were: Females (n=521): 5.93 ng/L (CI 95 % 5.29-8.48), Males (n=516): 9.79 ng/L (CI 95 % 6.37-17.41 ng/L), Total Population (n=1,037): 7.18 ng/L (CI 6.08-12.20 ng/L).

Conclusions: The MAGLUMI CLIA method met all the criteria for an hs-cTnI assay recommended by international guidelines. The hs-cTnI values measured with the CLIA method are higher in men compared to women at the same age, and also progressively increase after the age>55 years.