Performance evaluation of the high sensitive troponin I assay on the Atellica IM analyser.

Introduction: The Fourth Universal Definition of Myocardial Infarction Global Taskforce recommends the use of high sensitive troponin (hs-Tn) assays in the diagnosis of acute myocardial infarction. We evaluated the analytical performance of the Atellica IM High-sensitivity Troponin I Assay (hs-TnI) (Siemens Healthcare Diagnostics Inc., Tarrytown, USA) and compared its performance to other hs-TnI assays (Siemens Advia Centaur, Dimension Vista, Dimension EXL, and Abbott Architect (Wiesbaden, Germany)) at one or more sites across Europe. Materials and methods: Precision, detection limit, linearity, method comparison, and interference studies were performed according to Clinical and Laboratory Standards Institute protocols. Values in 40 healthy individuals were compared to the manufacturer's cut-offs. Sample turnaround time (TAT) was examined. Results: Imprecision repeatability CVs were 1.1-4.7% and within-lab imprecision were 1.8-7.6% (10.0-25,000 ng/L). The limit of blank (LoB), detection (LoD), and quantitation (LoQ) aligned with the manufacturer's values of 0.5 ng/L, 1.6 ng/L, and 2.5 ng/L, respectively. Passing-Bablok regression demonstrated good correlations between Atellica IM analyser with other systems; some minor deviations were observed. All results in healthy volunteers fell below the 99th percentile URL, and greater than 50% of each sex demonstrated values above the LoD. No interference was observed for biotin (≤ 1500 µg/L), but a slight bias at 5.0 g/L haemoglobin and 50 ng/L Tn was observed. TAT from was fast (mean time = 10.9 minutes) and reproducible (6%CV). Conclusions: Real-world analytical and TAT performance of the hs-TnI assay on the Atellica IM analyser make this assay fit for routine use in clinical laboratories.

Neuron-Specific Enolase Levels in Adults Under Venoarterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: We aimed to determine if elevations in serum neuron-specific enolase are associated with brain injury and outcomes in adults who require venoarterial extracorporeal membrane oxygenation. DESIGN: Prospective observational study. SETTING: Two ICUs of a university hospital, Paris, France. PATIENTS: Consecutive adult patients treated with venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock or in-hospital refractory cardiac arrest. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Serum sampled 1, 3, and 7 days after venoarterial extracorporeal membrane oxygenation cannulation was stored at -80°C and neuron-specific enolase concentrations were measured in batches at the end of the study. The association between neuron-specific enolase concentrations and outcomes (28-d mortality and poor outcome, defined by a score of 4-6 on the modified Rankin scale at 90 d) were explored by multivariable logistic regression, with neuron-specific enolase concentrations dichotomized according to median values. One-hundred three patients were included, of whom 26 (25%) received preextracorporeal membrane oxygenation cardiopulmonary resuscitation. Median (interquartile range) day-1, day-3, and day-7 neuron-specific enolase serum concentrations were 37 µg/L (26-51 µg/L), 25 µg/L (19-37) µg/L, and 22 µg/L (17-31 µg/L). After adjustment for Simplified Acute Physiology Score II, preextracorporeal membrane oxygenation cardiopulmonary resuscitation, and Sepsis Organ Failure Assessment score at time of cannulation, a day-3 neuron-specific enolase greater than 25 µg/L remained independently associated with 28-day mortality (adjusted odds ratio, 4.98; 95% CI, 1.86-13.32) and poor outcome at 90 days (adjusted odds ratio, 4.63; 95% CI, 1.81-11.84). A day-3 neuron-specific enolase threshold greater than 80 µg/L had a 100% specificity for prediction of both mortality (95% CI, 92-100%) and poor functional outcome (95% CI, 89-100%). In a subset of patients who underwent brain CT, neuron-specific enolase concentrations were significantly higher in patients diagnosed with stroke, as compared with those without stroke. CONCLUSIONS: In adult patients under venoarterial extracorporeal membrane oxygenation, day-3 serum neuron-specific enolase concentrations are independently associated with short-term mortality and poor functional outcomes. These findings deserve validation in a multicenter setting.

Multi-site performance evaluation and Sigma metrics of 20 assays on the Atellica chemistry and immunoassay analyzers.

Background The Atellica Solution comprises chemistry (CH) and immunoassay (IM) analyzers. Recently, six early adopter clinical laboratories across Europe evaluated the analytical performance of 20 CH and IM assays. To measure analytical performance quality, Sigma metrics were calculated for individual-site and pooled-site results. Methods Precision, detection capability, linearity, and method comparison studies were performed according to Clinical Laboratory Standards Institute protocols. Global Sigma metrics across sites were calculated from pooled data at the medical decision level using total allowable error (TEa) goals from CLIA for CH assays, and TEa goals from RiliBÄK for IM assays; and, the equation: Sigma metrics=%TEa-%bias/%CV. A pooled %CV was calculated by combining the imprecision obtained from individual sites. Bias calculations were performed against the ADVIA Chemistry system or ADVIA Centaur system using Deming regression analysis (Passing-Bablok regression for electrolytes) on the pooled-site data. The 103 individual-site Sigma metric calculations used individual-site imprecision and pooled-bias. Results The limits of blank and detection results agreed with the manufacturer's claims. Most assays were linear across the assay range tested. Pooled Sigma metrics were good or better (>4 Sigma) for 18 of 20 assays; and, acceptable for urea nitrogen (3.1) and sodium (3.9), the latter values attributable to higher imprecision at one of five sites. Conclusions Sigma metrics for data generated across multiple real-world sites evaluating the Atellica Solution demonstrated good or better performance of greater than 4 Sigma for 18 of 20 assays tested. Overall, results verified the manufacturer's claims that methods were fit for use in clinical laboratories.

Fecal calprotectin in inflammatory bowel diseases: update and perspectives.

Inflammatory bowel diseases (IBDs) are chronic diseases that result from the inflammation of the intestinal wall, suspected in any patient presenting with intestinal symptoms. Until recently, the diagnosis was mainly based on both clinical and endoscopic arguments. The use of an easy, fast, reliable, non-invasive, and inexpensive biological assay is mandatory not only in diagnosis but also in evolutionary and therapeutic monitoring. To date, the fecal calprotectin is the most documented in this perspective. This marker allows the discrimination between functional and organic bowel processes with good performance. The determination of the fecal calprotectin level contributes to the evaluation of the degree of disease activity and to monitoring of therapeutic response.