Chromogranin-A levels measured with automated immunoassay.

Measurement of chromogranin-A (CgA) levels is relevant for the diagnosis of neuroendocrine neoplasms. The use of CgA testing for risk stratification of cardiovascular diseases is also increasing. The objective of our study was to determine the performances and reference values of a novel automated assay for CgA testing. The new method was compared with an enzyme-linked immunosorbent assay. Our results showed that the performances of the automated assay were satisfactory and that the agreement between the two methods was excellent. The automation of CgA testing also reduced the turnaround time of analysis and, therefore, might contribute to a faster delivery of the results to physicians.

Aldosterone testing: evaluation of a novel automated immunoassay.

Aldosterone levels are increased in primary aldosteronism (PA) and might be triggered in several cardiovascular disorders. The aim of our study was to assess the analytical validity of a novel automated aldosterone immunoassay. Method comparison was also performed with a reference radioimmunoassay. We report for the first time the analytical validity of the LIAISON® aldosterone automated immunoassay. Such automated assay might therefore facilitate the screening of PA and risk stratification of cardiovascular diseases.

Measurement Nt-proBNP circulating concentrations in heart failure patients with a new point-of-care assay.

BACKGROUND: BNP (Brain Natriuretic Peptide) and Nt-proBNP (N-terminal-pro-Brain Natriuretic Peptide) are valuable markers for the diagnosis and prognosis of heart failure (HF). The AQT90 FLEX is a newly released random access analyzer for point-of-care (POCT) measurement. The aim of our study was to determine Nt-pro-BNP concentrations in HF patients with the POCT assay. METHODS: Nt-proBNP levels were measured in seventy seven HF patients and in thirty seven healthy volunteers. The results were compared with a central laboratory assay. RESULTS: Nt-proBNP levels measured with the AQT90 FLEX were significantly correlated with the comparison Nt-proBNP assay and were related to HF severity. CONCLUSIONS: Nt-proBNP testing with the AQT 90 FLEX analyzer is comparable to the central lab assay and may offer the advantages of POCT testing for the diagnosis and prognosis of heart failure.

Value of proBNP1-108 testing for the risk stratification of patients with systolic heart failure.

The study objectives were to determine the circulating levels of proBNP1-108, the precursor of B-type natriuretic peptide (BNP) and amino-terminal pro-BNP (NT-proBNP), in patients with systolic heart failure (HF) and to assess their prognosis value for cardiovascular (CV) death over a long-term follow-up. Seventy-three patients with systolic HF and 68 healthy volunteers were included. ProBNP1-108, BNP and NT-proBNP levels were measured with automated immunoassays and their predictive value for long-term survival was assessed through an 8 years follow-up. ProBNP1-108 levels were markedly increased in patients with systolic HF in comparison to healthy volunteers. In univariate proportional hazard model, survival was related to proBNP1-108, BNP, NT-proBNP, age, EF and glomerular filtration rate (eGFR). Kaplan-Meier survival curves according to proBNP tertiles diverged significantly, and the highest proBNP levels were related to patients with the highest risk of CV death. In a multivariate analysis including age, EF, proBNP1-108, BNP, NT-proBNP, and eGFR levels, NT-proBNP was the strongest predictor of long term CV death. Our study therefore demonstrated that high levels of proBNP1-108, measured with an assay with enhanced analytical specificity, are related to the long-term risk of cardiovascular death in systolic heart failure.

Significant, quantifiable differences exist between IgG subclass standards WHO67/97 and ERM-DA470k and can result in different interpretation of results.

OBJECTIVES: Accurate measurement of IgG subclass (IgGSc) levels are essential to aid in the diagnosis of disease states such as primary immunodeficiencies. However, there is no single standardisation of nephelometric and turbidimetric assays for these analytes and two reference materials have been utilised. We expand on previous reports and present data from a multi-site analysis that both identifies and quantitatively defines the differences in calibration resulting from the use of different reference materials. DESIGN AND METHODS: IgGSc antibodies in the serum specimens and reference materials were measured according to the manufacturers' instructions using commercially available IgGSc assays or components. RESULTS: Data from four independent sites showed that in spite of the different commercial suppliers of IgGSc assays calibrating to different reference materials, ERM-DA470k and WHO67 /97, the resulting calibrations were comparable for IgG1 and IgG2. However, for IgG3 and IgG4 the calibrations were significantly different. The use of assay specific normal ranges should compensate for these calibration differences, however, the two manufacturers' assays can give differing clinical classifications. The agreement between the different manufacturers' IgGSc assays was between 85.1% and 95.8% for all IgGSc assays, the discordance of sample classification for IgG1 and IgG2 assays was approximately 12% and 15% respectively, whilst that for IgG3 and IgG4 was 4% and 13% respectively. CONCLUSION: We discuss the similarities and differences between assays that utilise the different reference materials.

Quantification of serum free light chain kappa and lambda by the SPAPLUS analyser.

OBJECTIVE: Clinical assessment of the SPAPLUS® system for the determination of the serum free light chains kappa (κ FLC) and lambda (λ FLC) compared to the BNII®. DESIGN AND METHODS: 126 serum specimens from our routine activity were analysed on two different analysers: the BNII® (immunonephelometry, Siemens) and the SPAPLUS® (turbidimetry, Binding Site). We compared the absolute values of the serum κ FLC and λ FLC, as well as the FLC κ/λ ratio on both analysers. These results were further evaluated together with the clinical history of the patients. RESULTS: Regression analysis between the BNII® and the SPAPLUS® for κ FLC and λ FLC did not display any significant differences between both methods in the normal and pathological ranges. Nevertheless, some differences have been observed for some patients in the absolute value of the involved light chain, with potential clinical implications. CONCLUSION: The results show overall good concordance between both methods. However, it is recommended that the monitoring of patients affected by monoclonal gammapathies by measuring FLC, be performed in the same laboratory and by the same method. Moreover, the FLC results should always be interpreted together with other laboratory tests taking into account the patient's diagnosis.

Reduction of miscarriages through universal screening and treatment of thyroid autoimmune diseases.

BACKGROUND/AIMS: Universal screening for thyroid diseases during pregnancy is controversial. Targeted screening does not identify all women with thyroid dysfunction. Furthermore, antithyroid peroxidase antibodies (TPOAb) are suspected to be associated with an increased risk of fetal loss, premature delivery and hypothyroidism. The aim of our study was to assess the rationale behind universal screening and propose thyroxine treatment in particular cases. METHODS: Between January 2008 and May 2009, 537 consecutive iodine-supplemented women with a singleton pregnancy [441 TPOAb- controls and 96 TPOAb+ women (47 nontreated and 49 treated)] were evaluated using thyroid and obstetric parameters. According to our algorithm for thyroid screening in pregnancy, if thyroid-stimulating hormone (TSH) exceeded 1 mU/l in TPOAb+ women, 50 µg of levothyroxine (L-T4) was prescribed. RESULTS: The miscarriage rate was significantly higher in the nontreated TPOAb+ group compared with the treated group (16 vs. 0%; p = 0.02). Compared to the control group, TSH in TPOAb+ patients was higher at the first prenatal visit prior to L-T4 treatment (p < 0.01), while free thyroxine was higher than in the control group after the 20th week (p < 0.05). CONCLUSIONS: Our study supports the potential benefit of universal screening and L-T4 treatment for autoimmune thyroid disease during pregnancy. Efforts are still needed to further decrease miscarriage rates.

C-terminal FGF23 is a strong predictor of survival in systolic heart failure.

Fibroblast growth factor 23 (FGF23) is a bone-derived hormone involved in the regulation of phosphate and calcium metabolism. We have evaluated the levels of C-terminal FGF23 (Ct-FGF23) in 73 patients presenting heart failure with reduced ejection fraction (HF-REF) and assess their potential predictive value for long-term survival through a 6 years follow-up. Ct-FGF23 levels were markedly increased in HF-REF. In univariate proportional hazard model, survival was related to glomerular filtration rate (eGFR), intact parathyroid hormone (PTH), B-type natriuretic peptides (BNP) and Ct-FGF23. In a multivariate analysis including age, EF, PTH, BNP, Ct-FGF23, calcium, phosphorus and eGFR levels, Ct-FGF23 is the strongest predictor of long term CV death.

Measurement of NT-proBNP with LOCI technology in heart failure patients.

OBJECTIVES: The aim of our study was to determine NT-proBNP concentrations in heart failure (HF) patients with a luminescent oxygen channeling immunoassay (LOCI). DESIGN AND METHODS: Seventy HF patients were enrolled. NT-proBNP levels were measured with LOCI method and compared to a reference NT-proBNP assay. RESULTS: LOCI NT-proBNP levels were significantly correlated with the reference NT-proBNP assay and were related to HF severity. CONCLUSIONS: LOCI assay demonstrates performances close to the comparative assay for NT-proBNP testing and allows a significant reduction of the time of analysis.