CEST maps at 7T display higher APT and amine signal from the sagittal-sinus compared to elsewhere in the brain. We investigate CEST and NOE signals detected in ex-vivo blood under with varying oxygenation, haematocrit levels, pH and cell structure. Showing that human blood produces significant amounts of CEST and NOE, dominated by the cellular components of blood and independent of blood oxygenation. Clotting and lysing red-blood-cells has no impact on the observed CEST and NOE. We also observed increased APT and NOE with increasing pH. These result are important when interpreting exchange in conditions associated with blood volume change.