Serum Biomarkers in Surgical Patients

Blood samples were drawn after a 12-h fast, before surgery. Serum was separated and immediately frozen at –80 °C. Serum biochemical parameters were measured in duplicate. Serum glucose, cholesterol, HDL cholesterol and triglycerides were measured by standard enzymatic methods (Randox Laboratories Ltd, Antrim, UK). Insulin was measured with an immunoradiometric assay (BioSource International, Camarillo, CA, USA). The HOMA-IR was calculated from fasting insulin and glucose using the following equation: HOMA-IR=fasting insulin (μIU/ml) × fasting glucose (mol/l)/22.5. Serum survivin was measured by a sandwich ELISA (R&D Systems, Minneapolis, MN, USA). The assay sensitivity was 1.58–9.96 pg/ml and the intra- and inter-assay co-efficients of variance (CVs) were less than 5.5 and 9.5%, respectively.^{62 (link)} Serum leptin was measured by ELISA (R&D Systems). The minimum detectable concentration of human leptin is typically less than 7.8 pg/ml and the intra- and inter-assay CVs were less than 3.3 and 5.4%, respectively.