Turbidimetric immunoassay

Fasting blood samples were collected from each patient. Hemoglobin (Hb) level was measured using a standard cyanmethemoglobin method. Total lymphocyte count (TLC) was assayed automatically by a blood cell analyzer (Beckman Coulter LH750). Serum iron (Iron) levels were measured by performing a colorimetric endpoint assay with commercial kits from Roche China (Shanghai, China). Serum albumin (ALB), prealbumin (PAB), Retinol-binding protein (RBP), and creatinine (Cr) levels were assessed using turbidimetric immunoassay (Hitachi, Tokyo, Japan). Serum transferrin was detected by nephelometry on Behring BNⅡ automatic specific protein determination system and its supporting reagents (Siemens, Erlangen, Germany). Serum folic acid and vitamin B12 levels were measured using a chemiluminescent immunoassay. Serum C-reactive protein (CRP) was measured by particle-enhanced immunonephelometric assay (Dade Behring Inc., Newark, NJ, USA).

All participants had an overnight fast prior to blood sample collection. Hemoglobin (Hb) level was measured using a standard cyanmethemoglobin method. The serum albumin (ALB) levels were assessed using a turbidimetric immunoassay (Hitachi, Tokyo, Japan). Serum total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) were measured by the enzymatic method. Glycosylated hemoglobin A1c (HbA1c) was determined by a high-pressure liquid chromatography. The creatinine levels were measured by an enzymatic method with an automatic biochemical analyzer (Hitachi, Tokyo, Japan). Cystatin C was tested by latex-enhanced immunoprojection turbidimetry (Hitachi, Tokyo, Japan), and the test kit was provided by Bliolinks, Japan. Cr/CysC = creatinine (mg/dl)/cystatin C (mg/dl) × 100.