2.3.7. Blood Collection and CRP
CLOT
Participants were instructed to avoid strenuous physical exercise for 48 hours before each blood draw and completed a 24-h diet recall prior to blood collection in visit 1 in which they were asked to repeat prior to blood collection in visit 5. Whole blood was collected into serum separator tubes (Beckton Dickinson, East Rutherford, NJ, USA) by a certified phlebotomist, allowed to clot for 30-min at room temperature, then centrifuged at 2000 RPM for 15 min. The serum was pipetted into 1.5 mL microcentrifuge tubes (Eppendorf AG, Hamburg, Germany) and immediately stored in a −80 °C freezer. Serum concentrations of CRP were determined with a commercially available enzyme-linked immunosorbent assay (ALPCO Diagnostics, Salem, NH, USA). Microplates were read with an ELx800 BioTek microplate reader (BioTek Instruments, Inc., Winooski, VT, USA) at the recommended wavelength of 450 nanometers.