Principle Rouleaux formation is caused by an excess of high molecular weight protein in the serum. This is usually observed in patients with liver disease, multiple myeloma and other conditions associated with abnormal globulin levels. It does not affect the antiglobulin test because the serum is removed by washing.
Rouleaux formation can resemble or obscure agglutination.
Saline replacement technique may be required when strong rouleaux formation occurs. This manipulation should eliminate rouleaux without affecting agglutination. Procedure After the serum and the cells have been incubated, centrifuge and remove the serum without disturbing the cell button. Replace the serum with an equal volume of saline. Gently resuspend the cell button.