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Rouleaux formation on patient vaginal swab wet smear. Conditions that cause rouleaux formation include infections, multiple myeloma, Waldenström's macroglobulinemia, inflammatory and connective tissue disorders, and cancers. It also occurs in diabetes mellitus and is one of the causative factors for microvascular occlusion in diabetic retinopathy.
Erythrocyte aggregation is the main determinant of blood viscosity at low shear rate. Rouleaux formation also determines Erythrocyte sedimentation rate which is a non-specific indicator of the presence of disease. [6] Influence of erythrocyte aggregation on in vivo blood flow is still a controversial issue. [7]
Rouleaux formation; Sedimentation or settling stage; Packing stage - 10 minutes (sedimentation slows and cells start to pack at the bottom of the tube) In normal conditions, the red blood cells are negatively charged and therefore repel each other rather than stacking. ESR is also reduced by high blood viscosity, which slows the rate of fall. [7]
This is known as rouleaux formation, and it occurs more often if the levels of certain serum proteins are elevated, as for instance during inflammation. Separation and blood doping Red blood cells can be obtained from whole blood by centrifugation , which separates the cells from the blood plasma in a process known as blood fractionation .
Red cell agglutination can also occur in paroxysmal nocturnal hemoglobinuria [2]: 13 [3] and warm autoimmune hemolytic anemia. [ 4 ] : 88 In cases of red cell agglutination, the direct antiglobulin test can be used to demonstrate the presence of antibodies bound to the red cells.
Rouleaux causes red blood cells to stack together, which can mimic agglutination, causing a false positive result in the reverse grouping. This can be avoided by removing the plasma, replacing it with saline, and re-centrifuging the tube. Rouleaux will disappear once the plasma is replaced with saline, but true agglutination will persist.
Rouleaux of red blood cells under the microscope is an artifact which occurs when the blood sample at the edge of the coverslip [15] starts to dry out; where a large number of red blood cells clump together; or when the blood starts to clot when contacted with the glass. These artifacts are observed in only small, selected areas on the slide ...
Elevations in target cells are the result of a shift in the exchange equilibrium between the red blood cells and the cholesterol. Also, the surface membrane to volume ratio is increased.