The commonly recognized system of feline blood designates cats as A, B, or AB. The vast majority of cats in the United States are Type A, but the percentage of Type B cats increases in other countries, such as Australia.[7][8] In a study conducted in England, 87.1% of non-pedigree cats were type A, while only 54.6% of pedigree cats were type A.[9] Type A and B cats have naturally occurring alloantibodies to the opposite blood type, although the reaction of Type B cats to Type A blood is more severe than vice versa. Based on this, all cats should have a simple blood typing test done to determine their blood type prior to a transfusion or breeding to avoid the haemolytic disease (or neonatal isoerythrolysis).