Evaluation of the new Beckman Coulter Access hsTnI: 99th percentile upper reference limits according to age and sex in the Korean population

BACKGROUND: Defining the 99th percentile upper reference limits (URL) of cardiac troponin I (cTnI) is critical because it is clinically important in determining myocardial injury, and is variable among reagents, age, sex, or races. The analytical performance of the new, high- sensitivity reagent Beckman Coulter Access hsTnI was evaluated, and its 99th percentile URL was determined in the Korean population. METHODS: Analytical performances of Access hsTnI assay were evaluated including imprecision and limit of measurements. To define the reference limits, 600 healthy subjects were included with similar proportions of sex and age groups. RESULTS: Beckman Coulter Access hsTnI assay presented a limit of blank, detection, and quantitation at 10% CV of 0.32 ng/L, 0.63 ng/L, and 6.1 ng/L, respectively, and 98.3% of the healthy population showed cTnI above the limit of detection. The 99th percentile URLs were 9.5 ng/L (90% CI 7.4-14.9), 7.8 ng/L (90% CI 5.5-19.2 ng/L), and 11.3 ng/L (90% CI 8.0-15.7 ng/L) in 600 healthy participants, 300 women and 300 men, respectively with imprecision less than 10% CV. The median values and 99th percentile URLs of hsTnI were higher in men and the age group ≥50 years than in women and the age group <50 years, respectively. CONCLUSIONS: Access hsTnI assay met the performance criteria of the IFCC for high-sensitivity cTnI assays. Their 99th percentile URLs in the Korean population were lower than the manufacturer's claims. cTnI values were significantly different among different sex and age groups.