Elecsys probnp 2 assay

Venous blood samples of fasting patients with HOCM were collected within 2 days of echocardiography and 1 week of CMR examination. Plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) were measured with an electrochemiluminescent immunoassay (Elecsys proBNP II assay, Roche Diagnostics GmbH, Mannheim, Germany) on a Cobas 6000 analyzer (Roche Diagnostics), with a lower detection limit of 0.6 pmol/L. The inter-assay coefficient of variation was <4.6% and the intra-assay coefficient of variation was <4.2%. Serum CK-MB was determined by an immunoinhibition assay (creatine kinase-MB kit, Biosino, Beijing, China) on an Olympus AU-5400 analyzer (Olympus Diagnostics), with a lower detection limit of 3 IU/L. The inter-assay and intra-assay coefficients of variation were <6%.

Human ERFE was measured using a commercially available ELISA kit (SKU# ERF-001, Intrinsic Lifesciences) and performed following the manufacturers’ instructions. All ERFE measurements were conducted at the Christchurch Heart Institute, New Zealand. The inter-assay coefficient of variation (CV) of low (5 ng/ml, 37%) and high (35 ng/ml, 36%) quality control samples, with intra-assay CVs at 28% and 25% were derived over 16 and 29 assays, respectively. NT-proBNP measurements were assessed using the commercially available Elecsys proBNP II assay, a chemiluminescent two-site assay conducted on the Roche Cobas e411 analyser (Roche Diagnostics GmbH, Mannheim, Germany). NT-proBNP had an inter-assay CV of 5.5% and 5.7% for the low (845 pg/ml) and high (4860 pg/ml) quality control samples, respectively. Haemoglobin measurements were determined at the core biochemistry laboratories of the respective institutions.

Circulating levels of cTnI, NT‐pro BNP, and hs‐CRP were measured prior to all invasive procedures or treatment, when heart failure symptoms of patients could be controlled by regular oral medications. The time intervals between the blood tests of biomarkers and the completion of cardiac evaluations (Holter monitoring, TTE, and CMR) were usually within 7 days. Serum cTnI was determined using the immunochemiluminometric assay (Access AccuTnI, Beckman Coulter, California) on a Beckman Coulter Access 2 analyzer. The upper limit of its normal range (the 99th percentile of normal population) was 0.04 ng/mL, and the lower limit of detection was 0.01 ng/mL. Plasma NT‐pro BNP was examined by the electrochemiluminescent immunoassay (Elecsys pro‐BNP II assay, Roche Diagnostics, Mannheim, Germany) on a Cobas 6000 analyzer (Roche Diagnostics), with the lower detection limit of 0.6 PMol/L. A particle‐enhanced immunoturbidimetric assay (Ultrasensitive CRP kit, Orion Diagnostica, Espoo, Finland) was applied for the measurement of serum hs‐CRP on an Olympus AU‐5400 analyzer (Olympus Diagnostics). The lower detection limit of hs‐CRP was 0.25 mg/L.

Fasting blood samples were collected for all enrolled subjects within 2 days of TTE and 1 week of CMRI examination. Then the laboratory measurements were conducted by the clinical laboratory. All assays were performed within 4 h of blood collection by medical technologists who were unaware of any clinical information about the studied patients. Plasma FFA was measured with enzymatic assay (DiaSys Diagnostic Systems GmbH, Germany) on a Beckman-Coulter LX20. The intra-assay coefficient of variation was 1.03%, and the inter-assay coefficient of variation was 1.11%. Serum levels of triglycerides, high-density lipoprotein-cholesterol (HDL-C), and low-density lipoprotein-cholesterol (LDL-C) were measured by routine laboratory methods using an Olympus AU-5400 auto-analyzer (Olympus Corporation, Mishama, Japan). Plasma levels of N-terminal proB-type natriuretic peptide (NT-proBNP) were measured using an electrochemiluminescent immunoassay (Elecsys proBNP II assay; Roche Diagnostics, Mannheim, Germany). Hyperlipidemia was defined as those with serum LDL-C ≥3.37 mmol/L or triglycerides ≥1.70 mmol/L.

Fasting blood samples were collected from all participants and processed according to the manufacturers' instructions. Serum samples were stored at −80°C for 1–4 years. High-sensitivity cardiac troponin T (hs-cTnT) was measured on a Roche Cobas 6000 analyzer (Roche) with the Elecsys Troponin T hs assay (Roche), which has a limit of blank (LoB) of 3 ng/L and a limit of detection (LoD) of 5 ng/L, and achieves a 10% coefficient of variation (10% CV) at 13 ng/L. High-sensitivity cardiac troponin I (hs-cTnI) was measured on an Architect i2000 SR analyzer (Abbott Diagnostics) with the Architect STAT High Sensitive Troponin-I assay (Abbott), which has an LoB range of 0.7–1.3 ng/L and an LoD range of 1.1–1.9 ng/L, and achieves a 10% CV at 4.7 ng/L. N-terminal pro-B-type natriuretic peptide (NT-proBNP) was assessed on a Roche Cobas 6000 analyzer (Roche) with the Elecsys proBNP II assay (Roche), which has a LoD of 5.0 ng/L (LoB not reported), and achieves a 20% CV at 50.0 ng/L. NT-proBNP and hs-cTNT concentrations below the LoD or LoB respectively, were set at LoD/2 and LoB/2, respectively (21 (link)).

Venous blood samples were taken in the early morning after an overnight fast, within 2 days of TTE and 1 week of CMR examination. All of those samples were sent to the clinical laboratory of Fuwai hospital immediately and analyzed by medical technologists who were unaware of any clinical information about the study patients. Serum levels of creatinine, uric acid, total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting blood glucose (FBG), and high-sensitivity C-reactive protein (hs-CRP) were measured by routine laboratory methods using an Olympus AU-5400 auto-analyzer (Olympus Corporation, Mishama, Japan). SUA concentrations were determined using the uricase colorimetric assay (Uric Acid Kit, Biosino, Beijing, China). Plasma levels of N-terminal pro-B-type natriuretic peptide (NT-proBNP) were also measured, with an electrochemiluminescent immunoassay (Elecsys proBNP II assay, Roche Diagnostics GmbH, Mannheim, Germany) on a Cobas 6000 analyzer (Roche Diagnostics). The eGFR (mL/min/1.73 m²) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation [36 (link)]. Dyslipidemia was defined as those with serum LDL-C ≥3.37 mmol/L, TG ≥1.70 mmol/L, HDL-C <1.04 mmol/L, or the use of lipid-lowering drugs.