In 1910, Moss made the following classification:
Group 1, the serum of which does not agglutinate any corpuscles, while the corpuscles are agglutinated by the serum of Groups 2, 3 and 4.
Group 2, the serum of which agglutinates the corpuscles of Groups 1 and 3, while the corpuscles are agglutinated by the serum of Groups 3 and 4.
Group 3, the serum of which agglutinates the corpuscles of Groups 1 and 2, while the corpuscles are agglutinated by the serum of Groups 2 and 4.
Group 4, the serum of which agglutinates the corpuscles of Groups 1, 2 and 3 while the corpuscles are not agglutinated by any serum.
At the present time it is accepted that the four groups considered include all adult persons; i.e., that the classification is complete.
Before transfusing carry out the following tests:
From a vein take about 1 cc. of blood in a centrifuge tube containing 1% of sod. citrate salt solution; then shift the stopper of the blood system to a dry centrifuge tube and draw into it about 3 or 4 cc. of blood. Throw down the citrated blood, pipette off the supernatant fluid and wash the sediment with normal saline.
Again pipette off the saline after centrifuging and make a 10% emulsion of the red-cell sediment in normal saline.
Centrifuge the coagulated blood in the other tube and collect the serum which separates from the clot.