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Background: According to quality specifications required by international guidelines, the evaluation of the 99th URL value is a very difficult task that is usually beyond the capacity of a single laboratory. The aims of this article are to report and discuss the results of a multicenter study concerning the evaluation of the 99th percentile URL and reference change (RCV) of the ADVIA Centaur High-Sensitivity Troponin I (TNIH), recently distributed to the Italian clinical laboratories. Materials and methods: The reference population evaluated with ADVIA XPT method for the calculation of cTnI reference distribution parameters consisted of 1325 healthy adults subjects (age range from 18 to 86 years), including 653 women (mean age 50.7 years, SD 14.5 years) and 672 men (mean age 50.9 years, SD 13.8 years), well matched for both age (P =.8112) and sex (F/M = 0.97). Results: cTnI distribution values of reference population was highly skewed, while log-transformed cTnI values roughly approximated a log-normal distribution. Men have higher cTnI values than women throughout all the adult lifespan. Moreover, the subjects with age ≤ 55 years had significantly lower cTnI values than those with age > 55 years (p <.0001). Of note, 62% of women and 77% of men had equal or higher than cTnI values than the LoD value of the method (i.e., 2.2 ng/L). Conclusions: The results of the present study demonstrate that the ADVIA Centaur High-Sensitivity Troponin I using the XPT automated platform fits both the criteria and quality specifications required by the most recent international guidelines for high-sensitivity methods for cTnI assay.

Background: The Italian Society of Clinical Biochemistry (SIBioC) and the Italian Section of the European Ligand Assay Society (ELAS) have recently promoted a multicenter study (Italian hs-cTnI Study) with the aim to accurately evaluate analytical performances and reference values of the most popular cTnI methods commercially available in Italy. The aim of this article is to report the results of the Italian hs-cTnI Study concerning the evaluation of the 99th percentile URL and reference change (RCV) values around the 99th URL of the Access cTnI method. Materials and methods: Heparinized plasma samples were collected from 1306 healthy adult volunteers by 8 Italian clinical centers. Every center collected from 50 to 150 plasma samples from healthy adult subjects. All volunteers denied the presence of chronic or acute diseases and had normal values of routine laboratory tests (including creatinine, electrolytes, glucose and blood counts). An older cohort of 457 adult subjects (mean age 63.0 years; SD 8.1 years, minimum 47 years, maximum 86 years) underwent also ECG and cardiac imaging analysis in order to exclude the presence of asymptomatic cardiac disease. Results and conclusions: The results of the present study confirm that the Access hsTnl method using the DxI platform satisfies the two criteria required by international guidelines for high-sensitivity methods for cTn assay. Furthermore, the results of this study confirm that the calculation of the 99th percentile URL values are greatly affected not only by age and sex of the reference population, but also by the statistical approach used for calculation of cTnI distribution parameters.

It is well known that the results of immunoassay methods can be affected by specific or non-specific interferences, ranging from 0.4% to 4.0%. The presence of interference may greatly compromise the accuracy of immunoassay analyses causing an error in the measurement, producing false-positive or false-negative results. From a clinical point of view, these analytical errors may have serious implications for patient care because they can cause misdiagnosis or inappropriate treatment. Unfortunately, it is a very difficult task to identify the irregular analytical errors related to immunoassay methods because they are not detectable by normal laboratory quality control procedures, are reproducible within the test system, may be clinically plausible and are relatively rare. The first line of defense against erroneous results is to use in laboratory practice only immunoassay systems with the highest level of robustness against interference. The second line of defense is always taking into account the possibility of interference in immunoassay results. A correct approach should be addressed on identification of samples at high risk of interference. The attainment of this goal requires a critical review of the test result in relation to patient's clinical conditions and literature data, taking into account the analytical characteristics of the immunoassay system. The experts in immunoassay systems should make every effort to find some specific and reliable quality indicators for irregular analytical errors in order to better detect and monitor erroneous immunoassay results due to specific or non-specific interferences.

Come ricordano le commedie rinascimentali, l’inganno e la beffa sono parte del teatro quanto della vita vera. Machiavelli ne sintetizza l’essenza ne Il Principe: «colui che inganna troverrà sempre chi si lascerà ingannare» perché secondo le leggi di natura gli uomini sono ‘tanto semplici’ e ‘tanto obediscono alle necessità presenti’ da essere vittime facili e vulnerabili a causa o della loro stupidità o perché i bisogni, i desideri e le necessità impellenti li portano a mostrare il lato più debole. La beffa, come una lente deformante, amplifica tali difetti e imperfezioni fino a renderli estremi, caricaturali, esagerati. Li espone agli occhi del pubblico insieme alla vergogna e all’umiliazione delle vittime. Tuttavia nella commedia il beffato, succube dell’inganno che sfrutta la sue umane debolezze, vien messo in posizione tale da suscitare il riso anche quando la crudeltà dello scherzo risulta estrema. Per quanto grave l’umiliazione, non v’è ombra di patetico o di sofferente nelle sue disavventure. Né la crudeltà né la eventuale rozzezza degli scherzi diminuisce o intacca il risultato comico quando il meccanismo metateatrale bilancia nella commedia il grado di coinvolgimento e di distacco dello spettatore. Abel non ricorda forse che i personaggi nelle commedie non devono convincerci della loro esistenza, ma che tutto quello che devono fare, è farci ridere? Tuttavia, se sul piano narrativo si esalta la comicità pura e leggera, sul piano drammatico e metateatrale, nella breve incursione dietro le quinte, si lascia margine a un sentimento che va oltre il ridicolo: la commedia rinascimentale ama sperimentare nella zona di confine tra ridere e deridere, scherzare e schernire, tra leggerezza e umiliazione passando quasi impercettibilmente dal comico al tragico.