Abstract:

Objective To establish the pediatric reference interval of cardiac troponin I（cTnI） in Shanghai based on rapid immunochromatography,and to provide a reference for the clinical diagnosis of myocardial injury. Methods A total of 240 children aged from 7 months to 12 years were enrolled,and peripheral blood cTnI was determined by rapid immunochromatography. A methodology evaluation（accuracy,precision,minimum determination limit,linear range verification and method comparison） was carried out,and the reference interval of cTnI was determined by percentile method. Results The results of high-level and low-level quality control products determined by rapid immunochromatography were 4.73 and 0.49 ng/mL,respectively,which were in the expected range of quality control specification. The inter-day and intra-day precisions [coefficient of variation（CV）] for the quality control products with low level were 5.97% and 5.36%,and those with high level were 6.35% and 7.14%,respectively. They all met the requirements（CV<10%）. The minimum determination limit was 0.02 ng/mL,and the linear range was 0.028-26.400 ng/mL. There was a good correlation with chemiluminescence（r=0.988）. The 99th percentile of cTnI determination were 0.1 ng/mL,and the imprecision of the 99th percentile was 18.5%. The upper limit value of 99% reference interval（0.5 ng/mL） which was calculated by percentile method and the lower reference interval（<0.3 ng/mL） which was referred from reagent specification were used to establish the pediatric reference interval of serum cTnI based on rapid immunochromatography. The value of cTnI <0.3 ng/mL was negative,and the value of cTnI >0.5 ng/mL was positive. When the value of cTnI level was 0.3-0.5 ng/mL,further determination was required to perform and determine whether there was myocardial injury or not. Conclusions A rapid immunochromatography is preliminarily established for determining the reference interval of peripheral blood cTnI among children in Shanghai.

Key words: Cardiac troponin I, Rapid immunochromatography, Myocardial injury