EQA Scheme for hormone immunoassay: evaluation of laboratory performance through a scoring system

The External Quality Assessment (EQA) scheme Immunocheck for hormone immunoassay has been organised by our Institute since 1996 in co-operation with ProBioQual (Lyon, France); at present time more than 1000 laboratories are involved in the scheme which includes 18 analytes. Participants assay 18 control samples every year; statistics of the collected results are circulated sending back to the laboratories periodic and cumulative reports. To allow participants an easy evaluation of their own analytical performance, a new scoring system has been adopted. Each result is scored according to its deviation (from target value) expressed in SD unita (Z-score). In detail the scores are: 4(excellent) if Z <0.5, 3(good) if 0.5<Z<1, 2(sufficient) if 1 <Z<2, 1 (inadequate) if 2<Z<3, -2 (outlier) if Z >3. The sum of scores for all samples assayed in a control cycle, normalised by the maximum achievable total score, describes the analytical performance of the laboratory. Z-score is computed as the ratio of percent deviation from target and &#034;state-of-the-art&#034; imprecision. Method mean is assumed as target; state-of-the-art imprecision is computed as mean imprecision of the methods most used in the survey. To take account that imprecision depends on the analyte concentration, 3 CVs are computed corresponding to 3 concentration range. The table, in the document attached, reports for each analyte the concentration ranges and the state-of-the-art CVs (within-method, between-laboratories imprecision) computed from the Immunocheck data-base (results collected during 2001 EQA cycle).Non disponibil

Low-T3 Syndrome

Background— Clinical and experimental data have suggested a potential negative impact of low-T3 state on the prognosis of cardiac diseases. The aim of the present prospective study was to assess the role of thyroid hormones in the prognosis of patient population with heart disease. Methods and Results— A total of 573 consecutive cardiac patients underwent thyroid function profile evaluation. They were divided in two subgroups: group I, 173 patients with low T3, ie, with free T3 (fT3) <3.1 pmol/L, and group II, 400 patients with normal fT3 (≥3.1 pmol/L). We considered cumulative and cardiac death events. During the 1-year follow-up, there were 25 cumulative deaths in group I and 12 in group II (14.4% versus 3%, P <0.0001); cardiac deaths were 13 in group I and 6 in group II (7.5% versus 1.5%, P =0.0006). According to the Cox model, fT3 was the most important predictor of cumulative death (hazard ratio [HR] 3.582, P <0.0001), followed by dyslipidemia (HR 2.955, P =0.023), age (HR 1.051, P <0.005), and left ventricular ejection fraction (HR 1.037, P =0.006). At the logistic multivariate analysis, fT3 was the highest independent predictor of death (HR 0.395, P =0.003). A prevalence of low fT3 levels was found in patients with NYHA class III-IV illness compared with patients with NYHA class I-II (χ 2 5.65, P =0.019). Conclusions— Low-T3 syndrome is a strong predictor of death in cardiac patients and might be directly implicated in the poor prognosis of cardiac patients

Valutazione delle prestazioni analitiche dei metodi per la misura di Tg, AbTg e AbTPO: risultati del programma di VEQ Tg-check

Not availableIl programma di Valutazione Esterna di Qualit? Tg-check ? attivo da 5 anni; i laboratori nel ciclo 2008 sono 110 e circa il 70% di questi partecipa trasmettendo i risultati via internet collegandosi al sito web dei programmi di VEQ EQAS-CNR (http:/eqas.ifc.cnr.it). Dall\u27analisi cumulativa dei risultati dei 6 esercizi di controllo del ciclo 2007 risulta che i metodi per la misura della Tireoglobulina (Tg), nonostante l\u27uso di standard calibrati verso la stessa preparazione di riferimento (1? IRP CRM 457), continuano a produrre risultati molto diversi tra loro in particolare nei campioni contenenti anticorpi AbTg. In questi campioni, la variabilit? totale (CV tra-laboratori, tra-metodi) osservata nella VEQ ? molto elavata (74-83%) a causa dell\u27interferenza degli anticorpi endogeni nella misura della Tg; ? noto infatti che, ad oggi, tutti i metodi risultano pi? o meno interferiti dalla presenza di AbTg nel campione e questo provoca l\u27allargamento delle differenze sistematiche tra metodi. Nei campioni negativi per AbTg, invece, le differenze sistematiche tra metodi si riducono notevolmente (CV tra-laboratori, tra-metodi 20-40%)