Erythrocyte aggregation is at the root of many pathological processes and directly related to the phenomenon of erythrocyte sedimentation. Here we have investigated the kinetic characteristics of the erythrocyte aggregation and erythrocyte sedimentation of swine blood samples using the ESR (Erythrocyte Sedimentation Rate) technique and the UV-Vis spectrophotometer (absorbance) at a fixed wavelength (655 nm) versus time(seconds) of swine and human blood samples. For the ESR experiments of swine blood we have used samples with different hematocrits H= 20%, 25%, 30% e 35%. For the UV-Vis experiments of swine blood samples we have used the hematocrits H= 1%. 5%, 10%, 15% and 20% at a fixed 655 nm wavelength and for the human blood the hematocrits chosen were H=5%, 10%, 15% and 20%. Blood sedimentation rate data has been measured at 300s intervals during a period of 10,000s. While the UV-Vis assays had been carried through during 1.200s with data acquisition every 1s. ESR results show that the sedimentation rate of swine blood decreases as the hematocrit increases while the reverse phenomenon occurs in the UV-Vis experiments. From the ESR it is possible to distinguish three regions: I-the red blood cell aggregation process which is a plateau; II- the sedimentation process and III- a plateau indicating the end of sedimentation. With the UV-Vis it is possible to observe the sedimentation in much more detail with at least four regions: I-the aggregation slope; II-The aggregation and growth of roleaux followed by an "avalanche" of erythrocyte sedimentation; III-the sedimentation; IV- end of sedimentation.
ESR; erythrocyte aggregation; erythrocyte sedimentation speed
