Automatic analyzer 7600 020

The blood samples for laboratory tests were collected on the morning (between 6:00 and 7:00) of the second day after admission with an overnight fast. All samples were sent for testing immediately after collection. Serum β2M was measured with a particle-enhanced turbidimetric immunoassay method. The intra-assay coefficient of variation ranged from 2.4% to 3.8%, and the interassay coefficient of variation ranged from 1.7% to 2.2%. CRP was measured with an immune transmission turbidity method; other biochemical parameters, such as Cr, urea, and TG, were measured with an enzymatic method. All serum biochemical parameters were assayed using an automatic biochemical analyzer (HITACHI Automatic Analyzer 7600-020, Japan).
We collected baseline demographic and clinical information for all participants, including age, sex, and the presence of cerebral vascular risk factors such as hypertension and diabetes. Hypertension was determined by the previous use of an antihypertensive medication, SBP ≥ 140 mmHg or DBP ≥ 90 mmHg. Blood pressure was measured on the admission day using a mercury sphygmomanometer with a supine position of inpatients. Diabetes was determined by the previous use of an antidiabetic medication, fasting blood glucose ≥ 7.0 mmol/l or postprandial blood glucose after 2 h ≥ 11.1 mmol/l.

Serum creatinine level was measured using an enzymatic method by the Hitachi Automatic Analyzer 7600–020 (Hitachi, Tokyo, Japan). We estimated GFR using the Modification of Diet in Renal Disease (MDRD) Study equation for standardized serum creatinine [25 (link)]: estimated GFR (eGFR) = 175× (standardized serum creatinine in mg/dl)^-1.154 × age^-0.203 × 0.742 (if female). Estimated GFR is reported in ml/minute per 1.73 m² of body surface area [3 (link)].

Blood samples were collected after a 12-h fast using separation gel vacuum tube. Serum was obtained by centrifugation at 3000 g for 15 min in a microcentrifuge at room temperature and stored in aliquots at −80°C until biochemical assays. The biochemical variables, including alanine transaminase (ALT), aspartate aminotransferase (AST), triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), lipoprotein(a) (Lpa), homocysteine, fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (SCr), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and N-terminal-pro brain natriuretic peptide (NT-proBNP) were tested by standard methods using the Hitachi automatic analyzer 7600-020 (Hitachi) in the routine clinical laboratory. Serum FGF21 concentration was measured by quantitative human ELISA kits (DF2100, R&D Systems, Minneapolis, MN), following the manufacturer’s instructions. The sensitivity of detection was 8.69 pg/ml. The variation coefficients of intra- and inter-assays were <3 and <6%, respectively. All samples were detected in duplicate in a blinded manner.