Rouleaux will be present wherever the patient's serum is present, eg., in the reverse serum group, the autocontrol, and all phases of the antibody screen except the antiglobulin phase where the serum is washed away. Macroscopically, rouleaux usually presents as weak agglutination (e.g., 2+ or 1+ which easily disperses into weaker agglutinates). Microscopically, rouleaux can appear as coin stacks, or as a network of "coral" (if all the cells have joined together).