Biochemia Medica, Vol. 20 No. 3, 2010.
Izvorni znanstveni članak
Short-term increases of plasma cardiac troponin I are better evaluated by comparison with the reference change value
Giovanni Introcaso
orcid.org/0000-0001-5765-8696
; Unit of Laboratory Medicine, Cardiological Center Monzino, IRCCS, Milan, Italy
Monica Raggi
; Unit of Laboratory Medicine, Cardiological Center Monzino, IRCCS, Milan, Italy
Tiziana D’Errico
; Unit of Laboratory Medicine, Cardiological Center Monzino, IRCCS, Milan, Italy
Annalisa Cavallero
; Unit of Laboratory Medicine, Cardiological Center Monzino, IRCCS, Milan, Italy
Sažetak
Introduction: We have investigated consecutive troponin I measurements using the Reference Change Value (RCV) at low concentrations, in patients admitted in Emergency Department (ED).
Materials and methods: Patients admitted for chest pain (N = 103) were evaluated retrospectively on the basis of two consecutive cardiac tro-ponin-I (cTn-I) tests. The second test levels exceeding the "Critical Reference Change Value" (CrRCV), a quantity calculated on the basis of the first result and the RCV of cTn-I, were considered particularly relevant. Clinical cases were analysed matching the concentration change (significative or not) with acute coronary syndrome (clinically confirmed or not). Healthy individuals (N = 70) results and internal quality control results were evaluated for the calculation of, respectively, the biological and the analytical variation of plasma cTn-I.
Results: The cTn-I RCV was very high because of the high analytical variation of cTn-I in proximity of its decision limit, as shown by its imprecision profile study. Analysing data with the first result < 0.1 µg/L we have obtained an cTn-I RCV negative predictive value - NPV = 88% (95% CI = 82-92%). The 4 groups of patients have demonstrated a clinically significant difference (Chi square test; P < 0.001).
Conclusions: The RCV allows to statistically evaluating the cTn-I increased levels in presence of the high imprecision of commercial cTn-I assay at low concentrations. This parameter could be applied in medical practice only for low cTn-I concentrations around the decision limit for the myocardial necrosis.
Ključne riječi
cardiac troponin-I; reference change value; analytical imprecision; acute coronary syndrome
Hrčak ID:
59296
URI
Datum izdavanja:
5.10.2010.
Posjeta: 1.493 *