Tni ultra

The blood samples were obtained at baseline. Venous blood was drawn from the basilic vein. In the analysis, the peripheral blood count was marked with CELL-DYN Ruby (Abbott Diagnostics, Santa Clara, CA, USA). Fibrinogen, D-dimer, aPTT and INR were determined using STACompact Max (Diagnostica Stago, Parsippany, NJ, USA). Creatinine, total cholesterol, high-density lipoproteins, and triglycerides were analyzed using a photometric test (Roche Diagnostics GmbH, Mannheim, Germany).
The assessment of cardiac troponin involved the use of two assays: (a) a traditional immunoassay technique carried out from January 2012 to September 2014 (TnI-Ultra from Siemens, Advia Centaur, Deerfield, IL, USA), featuring a limit of detection of 6 pg/mL (0.006 ng/mL), a 99th percentile reference limit of 40 pg/mL (0.04 ng/mL), and a total imprecision of 10% at a concentration of 30 pg/mL (0.03 ng/mL) [23 (link)]; (b) the blood samples taken between October 2014 and December 2016 were analyzed by high sensitivity assays for cTnT (Roche Diagnostics, Basel, Switzerland), which have a limit of detection at 5 ng/L and a 99th percentile reference limit of 14 ng/L, with a total imprecision of 10% at a concentration of 13 ng/L.

Blood was drawn at study enrollment in both cohorts. Routine laboratory parameters were measured directly after blood withdrawal by standardized methods. Plasma and serum samples were collected, centrifuged, and frozen at −80 °C. A commercial contemporary sensitive assay (TnI-Ultra, Siemens Healthcare Diagnostics, Germany) was used to determine cTnI (cs-cTnI) on an ADVIA Centaur XP system. According to the manufacturer, this assay has a measuring range of 6–50,000 ng/L and coefficient of variation of less than 10% at 30 ng/L. The 99^th percentile reference limit based on a healthy population is 40 ng/L^{26 (link)}.

Blood was drawn directly upon admission. Routine laboratory parameters, including in-house troponin, C-reactive protein, creatinine, and creatinkinase-MB were measured immediately after blood withdrawal by standardized methods. Additionally, ethylenediaminetetraacetic acid plasma, citrate plasma, and serum samples were collected, centrifuged, and frozen at -80°C.
Investigational cTnI was determined using a commercial contemporary sensitive assay (TnI-Ultra, Siemens Healthcare Diagnostics, Germany) on an ADVIA Centaur XP system with measuring range of 6–50000 ng/L and lowest concentration with coefficient of variation of 10% or less at 30ng/L. The reference limit based on the 99^th percentile for a healthy population is 40ng/L [25 (link)].
B-type natriuretic peptide (BNP) was assayed on the ARCHITECT i System (Abbott Diagnostics, Germany) with analytical sensitivity of ≤10pg/ml and measuring range of 0–5000 pg/ml. Estimated glomerular filtration rate (eGFR) was calculated based on the abbreviated modification of diet in renal disease formula (MDRD)[27 (link)]. Based on availability of sample volume, BNP and cTnI levels were available in 417 and data on eGFR in 425 patients of 427 patients presenting with wide QRS complex.