Quantikine hs human il 6 immunoassay

High-sensitivity C-reative protein (hs-CRP) was measured by using the BNII nephelometer (Dade Behring Inc). Intra-assay and interassay analytic CVs ranged from 2.3% to 4.4% and from 2.1% to 5.7%, respectively. IL-6 was measured by using an ultrasensitive ELISA (Quantikine HS Human IL-6 Immunoassay, R&D Systems). The laboratory analytic CV for this assay was 6.3%. D-dimer was measured by using an immunoturbidimetric assay on a Sta-R analyzer (Liatest D-DI; Diagnostica Stago). The lower limit of detection was 0.01 μg/mL.

Biomarkers of inflammation under study were interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), fibrinogen, CRP, WBC count, and cystatin C (Cys C). Blood was collected during the in-home examination after an 8- to 10-h fast; sample processing and validation of the laboratory data have been previously reported [42 (link)]. CRP and Cys C were measured by particle-enhanced immunonephelometry using the BNII nephelometer (N High Sensitivity CRP, N Latex Cystatin C; Dade Behring) [43 (link)] and WBC count was measured using an automated analyzer (Beckman Coulter, Inc., Fullerton, CA, USA) [44 (link)] at the University of Vermont Laboratory for Clinical Biochemistry Research.
IL-6, IL-8, IL-10, and fibrinogen were measured in the cohort random sample in August 2012 at the University of Vermont Laboratory for Clinical Biochemistry Research. IL-6 was measured by ultra-sensitive ELISA (Quantikine HS Human IL-6 Immunoassay; R and D Systems, Minneapolis, MN, USA), IL-8 was measured by the Human Serum Adipokine Panel B LINCOplex Kit (Linco Research, Inc.; St. Charles, MO, USA), IL-10 was measured using the Milliplex MAP Human Cardiovascular Disease (CVD) Panel 3 (Millipore Corporation; Billerica, MA, USA) run as a single-plex assay, and fibrinogen was measured using the BNII nephelometer (N Antiserum to Human Fibrinogen; Siemens Healthcare Diagnostics, Deerfield, IL, USA).

Alanine amino-transferase (ALT) and glucose levels were determined using Diamond Diagnostic Kits (Diamond Diagnostics Inc., Holliston, MA). Tumor necrosis factor-α was quantified using an enxyme-linked immunosorbent assay (ELISA) kit (Endogen, Woburn, Massachusetts). Interleukin-6 levels were evaluated by ultra-sensitive ELISA kit (Quantikine HS Human IL-6 Immunoassay; R&D Systems, Minneapolis, Minnesota). Immunoglobin G levels were measured using ELISA kit (Sigma Chemical Co., St. Louis, Missouri), and CRP was measured using latex-enhanced immunonephelometry on a Behring BN II Nephelometer (Dade Behring). The VEGF level was estimated by quantitative ELISA kit (R&D Systems, United Kingdom). The assay methods used for estimation of different parameters using kits were performed in accordance with the manufacturer’s instructions. The nitrite concentration was assayed spectrophotometrically.^{16 (link)}