Application of stereological methods to evaluation of aggregation of red cells in 12.5 μ m slit: A photographic and statistical study

Stereological parameters d(Heyn), Lamda, and S^*/V^*, have been applied (for the first time, we believe) to evaluation of kinetics and morphology of aggregation of human red cells obtained from healthy and ill donors. Anticoagulated blood was allowed to flow at shear rate of 230 sec⁻¹ , flow was stopped am microphotographs taken at intervals till 12 minutes elapses. Aggregates increased in size for a period of 4 to 10 minutes, depending on blood sample. Sedimentation could be noticed after 10 minutes. Morphology of aggregates differed, rouleaux formation or clumping of red cells being quite clear under high magnification. Colour slides were analyzed by the Zeiss Videomat 2 image analyzer using a Zeiss Monochromator. Aggregation of red cells can be described by plotting stereological parameters vs square root of time. Morphology of aggregates can be described by plotting d(Heyn) vs Lamda, or d(Heyn) vs S^*/V^*. Different samples can be compared by comparing slopes and elevations of linear regressions, or by comparing means and standard deviations of stereological parameters.