Evaluation of analytical performance of immunoassay methods for cTnI and cTnT: From theory to practice.

Current guidelines worldwide recommend cardiac troponins I (cTnI) and T (cTnT) as the biomarkers of choice for the differential diagnosis of acute coronary syndrome (ACS), and the measurement of the 99th upper reference population limit (URL) value for cardiac troponins, with an imprecision of ≤10 CV%. Measuring the 99th URL of cTnI and cTnT is a challenging analytical task due to low biomarker concentrations present in healthy subjects. Therefore, since the year 2006, several manufacturers have established new generation cTnI and cTnT immunoassays with an improved analytical sensitivity in accordance with the quality specifications described in international guidelines, the more recent of which state that only immunoassays that meet the required quality specifications should be considered "high-sensitivity" methods.

Evaluation of analytical performances using standardized analytical protocols and comparison of clinical results of the new ADVIA BNP and NT-proBNP immunoassays for the Centaur XPT platform.

Background The study aim was to evaluate and compare analytical performances and clinical results of ADVIA BNP and PBNP methods using the Centaur XPT platform with those of Access BNP, using the DxI platform and the ECLIA NT-proBNP method, using the Cobas e411 platform, respectively. Methods Limits of blank (LoB), detection (LoD) and quantitation (LoQ) at 20% CV and 10% CV were evaluated according to international standardized protocols. The analytical parameters were assessed throughout a 90-working-day period using three curve calibrations.

Harmonization protocols for TSH immunoassays: a multicenter study in Italy.

Background: Systematic difference between thyroid-stimulating hormone (TSH) immunoassays may produce misleading interpretation when samples of the same patients are measured with different methods. The study aims were to evaluate whether systematic differences are present among TSH immunoassays, and whether it is possible to obtain a better harmonization among TSH methods using results obtained in external quality assessment (EQA) schemes.

Methods: Seven Italian clinical laboratories measured TSH in 745 serum samples of healthy subjects and patients with thyroid disorders.

Multicenter evaluation of the new immunoassay method for TSH measurement using the automated DxI platform.

Aim Of The Study: Recently, Beckman Coulter Diagnostics set up a new TSH immunoassay for the automated DxI platform. The aim of this study was to evaluate and compare the analytical performance and clinical results of this method with those of previous method.

Material And Methods: A multicenter study (named TSH ELAS Study) was organized using 593 serum samples, collected from healthy subjects and patients with thyroid disorders, and 13 control samples, circulated in an External Quality Assessment (EQA) scheme.

Analysis of the 2010-2012 results of the multicenter external proficiency study for 25-hydroxyvitamin D.

Background: Results collected from the 2010-2012 cycles of the 'Immunocheck' external quality assessment scheme for 25-hydroxyvitamin D, conducted by QualiMedLab CNR (Italy) and ProBioQual (France; 250 among Italian and French laboratories) are presented in this article.

Methods: Details of how QualiMedLab operates can be found in QualiMedLab website.

Results: Interlaboratory imprecision was 19 (2010), 15 (2011) and 13% (2012).

Systematic differences between BNP immunoassays: comparison of methods using standard protocols and quality control materials.

Background: Recent studies suggested that there are marked systematic differences among BNP immunoassays. In this study we compared the BNP data and clinical results obtained with different immunoassays, including a new method (ST-AIA-PACK, TOSOH Corporation).

Methods: BNP was measured on plasma-EDTA samples of healthy subjects (HS, n=126) and patients with heart failure (HF, n=31 NYHA I, II; n=46 NYHA III, IV) using the ST-AIA-PACK and the Triage Biosite (Beckman Coulter) methods.

Comparison of brain natriuretic peptide (BNP) and amino-terminal ProBNP for early diagnosis of heart failure.

Background: We compared the diagnostic accuracy of brain natriuretic peptide (BNP) and amino-terminal proBNP (NT-proBNP) for diagnosis of preclinical and mild heart failure (HF).

Methods: We assayed plasma NT-proBNP and BNP in 182 healthy controls and in a prospective cohort of 820 HF patients divided according to the American Heart Association/American College of Cardiology classification. These included 86 patients in stage A [mean (SE) ejection fraction 61% (1%); mean (SE) age 47 (2) years], 255 in stage B [65% (2%); 62 (1) years], 420 patients in stage C [35% (1%); 68 (1) years] and 59 in stage D [25% (1%); 74 (1) years].

Oxidative stress evaluated using an automated method for hydroperoxide estimation in patients with coronary artery disease.

Background: Reactive oxygen species (ROS) play a major role in the pathogenesis of different chronic and degenerative diseases, including atherosclerosis. However, the lack of feasible and reliable methods limits the spread of oxidative stress estimation for routine application in clinical chemistry laboratories. We have recently evaluated the analytical characteristics of an automated test for the measurement of hydroperoxides (HPs) and its performance in determining oxidative stress levels in a general population.

Analytical performance and clinical results of a fully automated MEIA system for brain natriuretic peptide assay: comparison with a point of care testing method.

The aim of this study was to evaluate the analytical performance of a recently available immunoassay for brain natriuretic peptide (BNP), based on microparticle enzyme immunoassay (MEIA, AxSYM System, Abbott Laboratories), whose analytical characteristics and clinical results were compared with those of a point of care testing (POCT) method (TRIAGE system, Biosite Diagnostics). The within-run and total imprecision of the MEIA system were 18.4% and 19.

Lactate production and catecholamine profile during aerobic exercise in normotensive OSAS patients.

Background And Purpose: The aim of the study was to evaluate the catecholaminergic activity and lactate concentration during exercise in normotensive patients with obstructive sleep apnoea syndrome (OSAS).

Patients And Methods: Thirteen normotensive patients affected by OSAS (mean age+/-standard error (SE), 52.6+/-2.

The relationship between anaerobic lactate threshold and plasma catecholamines during incremental exercise in hereditary spastic paraplegia.

Lower limb muscle chronic hyperactivity in hereditary spastic paraplegia (HSP) is the consequence of motor corticospinal tract involvement, which in turn has been hypothesized to be of mitochondrial origin. In order to assess skeletal muscle aerobic metabolism and sympathetic response during exercise in 10 HSP patients, we evaluated their blood lactate and catecholamine levels during an incremental workload bicycle exercise. Lactate, but not epinephrine or norepinephrine, levels were significantly higher in the HSP patients than in control subjects, in both resting conditions and during exercise.

Correlation between inflammatory response and markers of neuronal damage in coronary revascularization with and without cardiopulmonary bypass.

Off-pump coronary artery bypass graft (CABG) surgery may reduce the inflammatory response and the neuronal damage associated with conventional CABG on cardiopulmonary bypass. The purpose of this study was to explore the protective effect of off-pump surgery by assessing plasma inflammatory and neuronal injury markers. Forty-one patients with coronary artery disease undergoing elective CABG were examined: 21 on-pump (Group I) and 20 off-pump (Group II).