Patients erythrocytes are added in columns 1 and 2, while the serum is added to 3, 5 and 6. The sample is then incubated and the centrifuged.
Following centrifugation, a positive reaction results in a complex that does not pass through the gel, while a negative reaction passes easily to end up as the preciptate.
Analysis of a blood sample to ascertain the blood group, followed by storage of the sample for up to a week, to allow cross-match of compatible blood should it be required for transfusion.
The group and save sample is usually contains citrate as an anti-coagulant. It is important to ask the patient to give their name and date of birth. Samples should be labelled immediately. It is common for laboratories to require the forms to be hand-written. This has been asserted to avoid labelling errors, one mode of failure in which is to pick up a preprinted label for a different patient.