update September 2019: LABOKLIN holds the patent for the new improved test, which:

• is validated for all cat breeds except Domestic Shorthair, and
  
• can now check for more 'b' allele variants than ever before including the b3 which was identified by researchers at Laboklin, and
  
• can check for the 'c' allele which is resposnible for the AB serotyp, and
  
• only available at Laboklin

The AB system is the major blood group system in domestic cats. The common blood types are A and B. Cats with bloodtype B have anti-A antibodies at a high titer and cats with blood type A have anti-B antibodies at a low titer. Cats with the rare AB blood type do not have anti-A or anti-B antibodies. These natural antibodies can leed to bloodgroup incompatibility that can be lethal. The condition is known as Neonatal isoerythrolysis (NI), first symptoms are dyspnea, vomiting and agitation.

A recent study at Laboklin identified a number of new variants involved in determining the different blood groups in cats. Our Genetic Blood Group DNA test has now been updated with the new variants and as a result we can now screen all cat breeds except Domestic Shorthair for genetic blood groups. The updated test can detect the 'b' mutation which is reposnible for blood group 'B' more accurately than before and in more breeds, and the 'c' mutation which is repsonsible for blood group 'AB' in Ragdoll and Bengal can now be detected.

The test is valid for all cat breeds except: Domestic Shorthair.

The new improved test is more comperhensive than any other commercially available tests.

Neonatal isoerythrolysis (NI):

Neonatal isoerythrolysis occurs when kitten with blood group A or AB (also known as C) are born to a queen with blood type B. A-type and AB-type kittens absorb the anti-A antibodies from the breast milk. The hemolytic disease that ensues can be lethal.

This incompatibility reaction, especially important for breeders, is neonatal isoerythrolysis (NI). Neonatal isoerythrolysis in cats, also called fading kitten syndrome, is a dissolution of the red blood cells.

Only new born cats with blood groups A or AB (also known as C) whose mother has blood group B are affected by NI. In pedigree catteries, neonatal isoerythrolysis may occur in first-born and multiparous queens with blood group B, if they are mated to toms having blood groups A or AB (also known as C).

The kittens, with blood group A and AB (also known as C), which were born healthy, however, take up the mother's antibodies with the colostrum. These bind to the erythrocytes, which are then destroyed. Anaemia, excretion of protein in the urine and jaundice are the consequences, so that the kittens usually die within the first week of life. In some cases, the intestinal barrier is already closed at the time of birth, so that the absorption of the immunoglobulins by the kitten is prevented. Therefore, some theoretically at-risk kittens may not develop neonatal isoerythrolysis. Thus, not all kittens with blood groups A and C whose mother is type B develop NI.

Good to know Blood type B kittens whose mothers have blood group A do not develop NI. This is due to the low anti-B antibody titre in blood group A queens.

As a rule, new born kittens with clinical symptoms cannot be treated successfully. However, neonatal isoerythrolysis can be prevented by determining the blood groups of possible breeding partners in advance and avoiding mating between queens with blood group B and toms with types groups A or AB (also known as C). However, if such mating does occur, the kittens with blood groups A or AB (also known as C) should be separated from their type B mother in the first 16-24 hours after birth to prevent antibody uptake before the intestinal barrier is closed. For the genetic blood group determination, Laboklin requires either an EDTA blood sample (0.5 - 1 ml) or 2 cheek swabs. The sample run time after sample arrival is approx. 3-5 working days.

The differences between blood types is determined by the activity of cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH). CMAH is only active in type A erythrocytes and either absent or non-functional in type B red blood cells. This inactivity is caused by different mutations in the CMAH gene.

The original mutation which is causative for blood type B was found by Leslie A. Lyons research team and allows for correctly identifying 86 % of all type B cats which still left 14 % of serological type B cats misidentified, especially Ragdolls and Turkish Angora cats.

Our own research shows that additional screening for two other novel mutations correctly identifies 99% of all type B cats. By determining just these two novel variants all type A and B Ragdolls were identified correctly. These two mutations were also found to be causative for blood type B in Turkish Angora, Neva Masquerade, Scottish Fold as well as Domestic Shorthair cats

Leslie A. Lyons research team found another variant in CMAH which is responsible for blood type C (AB) in Ragdolls. We found that this specific mutation is not exclusively found in Ragdolls even though it is rare in other breeds. Type C Bengal cats could also be correctly identified by this mutation and it was also found in British Shorthairs, Maine Coons and Scottish Fold cats.

Since 2017 we practice a genotyping scheme with four variants, three of those to identify blood type B cats correctly and one additional to include the most common variant for blood type C.

The test now detects three genetic variants for the 'b' allele (268T>A, 179G>T, 1322delT) and one variant for the 'c' allele (364C>T).

The 3 'b' variants are also known as b1, b2, and b3.