Quantikine high sensitivity human il 6 kits

To quantify levels of IL-6 and CRP, 10ml of blood were collected into EDTA tubes (Becton–Dickinson, Franklin Lakes, NJ), held on ice, and centrifuged within 2 hours of collection for 15 minutes at 1500g. Plasma was then aspirated, aliquoted, and frozen at −80 °C until assay. Plasma levels of IL-6 were quantified using Quantikine High Sensitivity human IL-6 kits (R&D Systems, Inc., Minneapolis, MN), an enzyme-linked immunosorbent assay (33 (link)) with an intra-assay coefficient of variation of 4% and inter-assay coefficient of variation of 10%. The minimal detectable level of IL-6 was 0.156 pg/ml. CRP was measured using the Dade Behring N High Sensitivity CRP turbidimetric immunoassay (Dade Behring Diagnostics, Marburg, Germany) on the BN ProSpec. We excluded data from 8 participants with both IL-6 values above 10 pg/ml and CRP values above 10mg/L, in order to rule out participants who were likely to be experiencing an acute infection at the time of data collection (34 (link)). To address non-normal distribution, IL-6 and CRP variables were transformed using a natural log function.

Participants underwent a blood draw to assess levels of IL-6 (pg/ml), CRP(mg/L) and fibrinogen (mg/dL) levels. Blood samples were collected into Vacutainer tubes (Becton–Dickinson, Franklin Lakes, NJ) containing EDTA (IL-6, CRP) or sodium citrate (fibrinogen), held on ice, and centrifuged within 2 h of collection for 15 min at 1500g. Within two hours of collection of 10 ml of blood, the samples were centrifuged for 15 minutes at 1500g. Plasma was then aspirated, aliquoted, and frozen at −80 °C until shipped for assay. All inflammatory marker values were determined by a Clinical Laboratory Improvement Amendments (CLIA) certified University of California at Los Angeles Medical Clinical Laboratory using standardized methodologies and reporting guidelines. Plasma levels of IL-6 were quantified using Quantikine High Sensitivity human IL-6 kits (R&D Systems, Inc., Minneapolis, MN), an enzyme-linked immunosorbent assay (ELISA) with an intra-assay coefficient of variation of 4% and inter-assay coefficient of variation of 10%. CRP was measured using the Dade Behring N High Sensitivity CRP turbidimetric immunoassay (Dade Behring Diagnostics, Marburg, Germany) on the BN ProSpec. Fibrinogen levels were determined by a commercial laboratory (Quest Diagnostics, Los Angeles, CA) through use of a clotting assay (Clauss, 1975) and reported in mg/dL.

To quantify levels of IL-6 and CRP, 10 ml of blood was collected into EDTA tubes (Becton-Dickinson, Franklin Lakes, NJ), held on ice, and centrifuged within 2 hours of collection for 15 minutes at 1500g. Plasma was then aspirated, aliquoted, and frozen at −80°C until assay. Plasma levels of IL-6 were quantified using Quantikine High Sensitivity human IL-6 kits (R&D Systems, Inc, Minneapolis, MN), an enzyme-linked immunosorbent assay (33) with an intra-assay coefficient of variation of 4% and interassay coefficient of variation of 10%. The minimal detectable level of IL-6 was 0.156 pg/ml. CRP was measured using the Dade Behring N High Sensitivity CRP turbidimetric immunoassay (Dade Behring Diagnostics, Marburg, Germany) on the BN ProSpec. Fibrinogen levels (mg/dL) were determined by a commercial laboratory (Quest Diagnostics, Los Angeles, CA) through use of a clotting assay. Data from 8 participants with IL-6 values greater than 10 pg/ml and CRP values greater than 10 mg/L, suggesting the presence of acute illness, were excluded (McCaffery, Marsland, Strohacker, Muldoon, & Manuck, 2012 (link)).