Blood: crossmatching

Overview

• Major crossmatch detects alloantibodies in recipient plasma against donor red cells.
• Minor crossmatch detects alloantibodies in donor plasma against recipient red cells.
• An incompatible major crossmatch can result in an acute hemolytic transfusion reaction when donor erythrocytes are destroyed by alloantibodies in the recipient's plasma.
• A minor crossmatch incompatibility is less likely to cause a transfusion reaction because the volume of donor plasma is small and becomes markedly diluted in the recipient.
• Transferring incompatible blood can   →   acute transfusion reaction     (which can be fatal) and certainly results in shortened lifespan of transfused cells.

Uses

Alone

• Simple test to screen against more serious blood transfusion reactions    .
• Moderate to high titered anti-A alloantibodies exist in nearly all in Type B cats. So if a Type B cat is given Type A blood, severe, acute intravascular hemolysis can occur.
• May be used to diagnose blood type incompatibilites leading to neonatal isoerythrolysis     by crossmatching the queen and kittens.

Other points

• There is one commonly recognized feline blood group system (A-B)and 3 feline blood types associated with it: Types A, B and AB    .
• Natural alloantibodies to blood type antigens exist, ie most Type A cats have anti-B alloantibodies (but usually low titered) and all Type B cats have anti-A alloantibodies (usually moderate or high titered). Type AB cats do not have naturally occurring alloantibodies in their blood.
• Reactions will occur between blood of different types.
• Geographical variations exist in the prevalence of the different blood types.
• Generally most non-pedigree cats are Type A, but a significant number are of Type B, with smaller numbers of Type AB. The prevalence of Type B cats amongst non-pedigrees in the UK, Australia, France and Italy appears to be greater than originally thought.
• In both the UK and USA, as well as other countries, certain breeds have been identified which appear to have a particularly high prevalence of Type B cats, especially the Devon Rex     and British shorthairs    , but also the Ragdoll     and Birman    . Type B cats are also commonly seen amongst Persians    , Somalis    and Abyssinians    .
• Type B cats do not seem to be a feature of the Siamese    , Burmese    , Russian Blue    , Ocicat     or Oriental Shorthair     cats.
• Although cross-matching techniques are well described in the literature (slide and microwell ag-glutination tests) and are feasible to do in a clinic situation, they are quite laborious and time consuming.
• The introduction of simple in-house tests for typing feline blood (eg cards by Rapid Vet-H Feline     or strip tests - Quick Test A +B by Alvedia    ) makes blood typing simpler than crossmatching.
  However blood typing does not replace crossmatching. Ma jor and minor cross-matching of blood may still have to be performed in blood-typed cats: firstly if they have already received a transfusion (>5 days previously), as the first transfusion, of even matched blood, may induce production of antibodies against red cell antigens other than those involved in the A-B blood group system. Secondly, if a non-A-B blood group system incompatibility is suspected, and one of these has recently been reported (Mik antigen) as mediating blood transfusion reactions.
• Some advise performing blood typing and crossmatching before all transfusions although this may not be practical.

Result data

Normal (reference) values

• Control should be performed with recipient red cells and serum, no agglutination or hemolysis should be seen.

Abnormal values

• Agglutination or hemolysis in major cross match implies recipient has antibody against donor red cells   →   major crossmatch incompatibility.

Errors and Artifacts

• If autoagglutination occurs in recipient control, cross match results cannot be interpreted (immune-mediated hemolysis with auto-agglutination interfering with cross match).

• Fresh blood must be used or results are very unreliable.
• Blood type of recipient cat can be inferred if donor cat blood type is known.
• If no incompatibility in major and minor cross match - donor and recipient have same blood type.

Sources

Publications

Refereed papers

• Recent references from PubMed.
• Forcada Y, Guitian J & Gibson G (2007) Frequencies of feline blood types at a referral hospital in the south east of England. JSAP 48, 570-573 PubMed.
• Weinstein N M, Blais M C, Harris K, Oakley D A, Aronson L R & Giger U (2007) A newly recognized blood group in domestic shorthair cats; the Mik red cell antigen. JVIM 21, 287-292 PubMed.
• Grot-Went & Giger U (1995) Vet Clinics N America 25 (6), 1305-1322.
• Giger U & Bucheler J (1991) Transfusion of Type-A and Type-B blood to cats. JAVMA 198, 411-418.
• Knottenbelt C M, Addie D D, Day M J & Mackin A J (199) Determination of the prevalence of feline blood types in the UK. JSAP 40, 115-118.