ADHESION AND INTERFERENCE IMAGES OF UNFIX ED ERYTHROCYTES

For the analysis of deformability in microcirculatory investigations a n exact understanding of red blood cell (RBC) geometry is required. To extend knowledge we introduce a new morphological feature of resting unfixed erythrocytes by means of an inverted reflection contrast micro scope (RBC). By assessing the interference patterns caused by RCM eryt hrocytes can be classified according to the depth of their central con cavity which depends on the flexibility of the RBC. Moreover, the RBC adhesion can be di directly observed. We found out that: 1. Five types of normocytes can be distinguished in RCM. 2. In phase contrast the s ize distribution of RBC without central concavity (type 5, 11.53% of a ll normocytes) shows peaks at 48 mu m(2) and 52 mu m(2). 3. Image anal ysis reveals two size categories of relative adhesion areas. One categ ory consists of type 1 and 2 (relative adhesion area 25.63%), the othe r of the types 3 to 5 (relative adhesion area 39.91%). Besides, RCM al lows the reliable identification of pathologic erythrocytes in unstain ed specimens.