Elecsys il 6

Human IL-6, tumor necrosis factor α (TNF)α, and IL-1β were examined using the Quantikine HS ELISA kits HS600C, HSTA00E, and HSLB00D from R&D Systems. IL-6Rα and CRP were measured using the Quantikine kits DR600 and DCRP00. LBP was analyzed with the Human LBP ELISA kit HK315 from Hycult Biotech. Platelet-poor plasma was diluted 100-fold for IL-6Rα, 200-fold for CRP, 500-fold for LBP, or used whole for IL-6 and TNFα measurements. ELISAs were performed according to manufacturer instructions. IL-6 measurements of six hemophilia patients with acute bleeding were performed using electrochemiluminescence immunoassay (ECLIA; Elecsys IL-6, Roche).

To examine the effects of short-term storage on IL-6 levels, venous blood was collected into a vacuum blood collection tube (4- × 5-mL tubes containing EDTA as an anticoagulant; Terumo Co., Tokyo, Japan). Prior to blood collection, 14 healthy participants and medical staff were on standby. To standardize the analysis times, venous blood samples were collected from all participants at the same time by assigning one staff member to each participant. Blood samples were stored on ice to exclude the effects of temperature differences prior to analyses. Immediately after collection, blood samples were carried to a laboratory and centrifuged using a refrigerated centrifuge (Model 6200, Kubota Co., Tokyo, Japan) at 2000 × g for 10 minutes at 4 °C to obtain plasma. The completion of this centrifugation step was defined as 0 minutes (Figure 1). The numbers of WBCs, RBCs, and PLTs were measured using a blood cell analyzer (XN-9000, Sysmex Co., Tokyo, Japan). Next, 30 µL of plasma was analyzed every 30 minutes using an ECLIA platform (Cobas 8000 [e602], Roche Diagnostics K.K., Tokyo, Japan) and 96-spot IL-6 ECLIA plates (Elecsys IL-6, Roche Diagnostics K.K.).
Clinical information and results from sample analyses were collected and entered in a structured database by research staff who had no direct contact with study participants.