ACVIM consensus statement on the treatment of immune thrombocytopenia in dogs and cats

Management of immune thrombocytopenia (ITP) in dogs and cats is evolving, but there are no evidence-based guidelines to assist clinicians with treatment decisions. Likewise, the overall goals for treatment of ITP have not been established. Immunosuppressive doses of glucocorticoids are the first line treatment, but optimal treatment regimens beyond glucocorticoids remain uncertain. Additional options include secondary immunosuppressive drugs such as azathioprine, modified cyclosporine, and mycophenolate mofetil, usually selected based on clinician preference. Vincristine, human IV immunoglobulin (hIVIg), and transfusion of platelet or red blood cell-containing products are often used in more severe cases. Splenectomy and thrombopoietin receptor agonists are usually reserved for refractory cases, but when and in which patient these modalities should be employed is under debate. To develop evidence-based guidelines for individualized treatment of ITP patients, we asked 20 Population Intervention Comparison Outcome (PICO) format questions. These were addressed by 17 evidence evaluators using a literature pool of 288 articles identified by a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations. These were integrated by treatment domain chairs and then refined by iterative Delphi survey review to reach consensus on the final guidelines. In addition, 19 non-PICO questions covering scenarios in which evidence was lacking or of low quality were answered by expert opinion using iterative Delphi surveys with panelist integration and refinement. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The rigorous consensus process identified few comparative treatment studies, highlighting many areas of ITP treatment requiring additional studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Diagnosis of Immune Thrombocytopenia in Dogs and Cats.

Evaluation of post-transfusion RBC alloimmunization in dogs using a gel-column crossmatch with and without anti-canine globulin enhancement

A blood crossmatch is essential to ensure RBC compatibility for previously transfused dogs. There is no gold standard crossmatch method for dogs, although the standards used most commonly by academic institutions and reference laboratories are the tube and gel-column crossmatches. Addition of anti-canine globulin (ACG) has been suggested to increase detection of RBC incompatibilities. Our objective was to determine if there is a correlation between results of a standard and an ACG-enhanced gel-column crossmatch in detecting post-transfusion RBC alloimmunization. Pre- and post-transfusion serum or plasma samples were obtained from 33 dogs for major crossmatches to 1-6 (median: 3) blood donors. Crossmatches were performed with (n = 202) and without (n = 202) ACG, with results scored by 4 observers, 3 of whom were anonymized. Ten of 33 (30%) dogs had major crossmatch incompatibilities post-transfusion. RBC incompatibilities (2-4+ agglutination) were detected only with ACG in 4 dogs, only without ACG in 3 dogs, and with both methods in 3 dogs. There was fair correlation between crossmatch methods for determination of compatibility (ρ = 0.34; p < 0.001) and incompatibility (ρ = 0.35; p < 0.001) scores. Among 4 observers, there was near-perfect agreement in determining compatibility (κ = 0.97; p < 0.001) and substantial agreement in overall scoring of incompatibility (κ = 0.77; p < 0.001). Our results suggest that detection of RBC incompatibilities in dogs can be maximized by performing a gel-column crossmatch both with and without ACG enhancement.

Effect of donor blood storage on gel column crossmatch in dogs

BACKGROUND

Compared with fresh blood, stored equine donor blood results in spurious tube crossmatch incompatibilities. Interpretation of blood crossmatch results is considered subjective.

OBJECTIVES

We aimed to determine if the duration of canine donor blood storage impacts compatibility testing using a standard gel column crossmatch and evaluate interobserver variation in the interpretation of crossmatch results.

METHODS

Observational study. Whole blood segments were obtained from 23 canine packed red blood cell (RBC) units for use in crossmatches after storage for 0, 7, 14, 21, 28, and 35 days. Major and minor crossmatches were performed using serum and RBCs, respectively, from two to three healthy "recipient" dogs per unit. All crossmatch results were interpreted by four observers, of whom three were blinded.

RESULTS

All major crossmatches (n = 61) were compatible on day 0 and remained compatible through day 35 of storage. All minor crossmatches (n = 69) were compatible at all time points, except for five donor pairs with 1 to 3+ agglutination. Repeat testing of these five donor pairs confirmed crossmatch incompatibilities on days 0 through 35, with no change in the degree of incompatibility over time. There was substantial agreement among four observers in determining compatibility (κ = 0.94) and scoring incompatibility (κ = 0.76).

CONCLUSIONS

The current practice of performing canine crossmatches with whole blood segments stored for up to 35 days is acceptable, with no spurious changes in compatibility expected over time. The substantial interobserver agreement suggests that the gel column is suitable for performing canine crossmatches in a laboratory setting with multiple personnel.

Validation of a cage-side agglutination card for Dal blood typing in dogs

BACKGROUND

Although 98% of the canine population is Dal-positive, Dal-negative dogs are more common in some breeds such as Doberman Pinschers (42.4%) and Dalmatians (11.7%), and finding compatible blood for these breeds may be challenging, given limited access to Dal blood typing.

OBJECTIVES

To validate a cage-side agglutination card for Dal blood typing and determine the lowest packed cell volume (PCV threshold) at which interpretation remains accurate.

ANIMALS

One-hundred fifty dogs, including 38 blood donors, 52 Doberman Pinschers, 23 Dalmatians and 37 anemic dogs. Three additional Dal-positive canine blood donors were included to establish the PCV threshold.

METHODS

Dal blood typing was performed on blood samples preserved in ethylenediaminetetraacetic acid (EDTA) <48 hours using the cage-side agglutination card and a gel column technique (gold standard). The PCV threshold was determined using plasma-diluted blood samples. All results were read by 2 observers, blinded to each other's interpretation and to the sample's origin.

RESULTS

Interobserver agreement was 98% and 100% using the card and gel column assays, respectively. Overall, the sensitivity and specificity of the cards were 86%-87.6% and 96.6%-100%, respectively, depending on the observer. However, 18 samples were mistyped using the agglutination cards (15/18 by both observers): 1 false-positive (Doberman Pinscher), and 17 false-negative samples including 13 anemic dogs (PCV range, 5%-24%; median, 13%). The PCV threshold allowing reliable interpretation was determined to be >20%.

CONCLUSIONS AND CLINICAL IMPORTANCE

Dal agglutination cards are reliable as a cage-side test, but results should be interpreted cautiously in severely anemic patients.

Production and characterization of a murine anti-dal monoclonal antibody for blood typing in dogs

Considering the strong immunogenicity of the Dal antigen, and that > 98% of dogs, including blood donors, are Dal-positive, finding compatible blood for a previously transfused Dal-negative patient may be challenging. This is exacerbated by limited access to typing reagents, which currently rely on polyclonal antibodies (PAb) produced following sensitization of dogs. Therefore, the objective of this study was to produce and characterize an anti-Dal murine monoclonal antibody (MAb). Conventional hybridoma technology was used to produce MAb directed against canine red blood cells (cRBC). Briefly, female BALB/c mice were immunized via repeated intraperitoneal injections of washed Dal-positive cRBC (DEA 1,3,7 negative; DEA 4,5 positive) until serologic titers were sufficient (>1:1000). Following fusion with myeloma cells, 573 hybridoma cell culture supernatants were obtained and screened for MAb of interest using a gel column agglutination technique and known Dal-negative and Dal-positive cRBC. Fifteen supernatants led to cRBC agglutination, but only one had the desired pattern (i.e. anti-Dal). To assess its specificity and sensitivity, Dal blood typing of 62 canine EDTA-blood samples was performed using the anti-Dal MAb and two canine PAb: 45 Dal-positive and 17 Dal-negative were identified with 100% agreement between reagents (kappa =1). The anti-Dal MAb produced was further determined to be an IgG1. Conventional hybridoma technology, aided by a gel column technique, has enabled the production of a murine MAb specific against the canine Dal antigen. This will ensure long-term perennity of Dal blood typing, facilitate clinical management and research, as well as avoid resorting to repeat dog sensitization.

Alloimmunization in dogs after transfusion: A serial cross-match study

BACKGROUND

Cross-matching is performed to determine the serological compatibility of donor and recipient blood. Current guidelines recommend that cross-matching should be performed in dogs when an initial transfusion was performed more than 4 days ago or when the transfusion history is unknown.

HYPOTHESIS

Determination at what time point alloantibodies are detected in dogs after transfusion. The hypothesis was that dogs would form alloantibodies within 4 days after a transfusion.

ANIMALS

Twenty-one anemic dogs were transfused and monitored for at least 4 subsequent days. Exclusion criteria were persistent red blood cell (RBC) agglutination and a previous transfusion.

METHODS

Prospective observational study. Cross-matching was performed before the initial DEA 1-compatible transfusion and on days 1, 2, 3, and 4 and if possible, between day 5 and 28, using the tube method without enhancement (major cross-match, recipient controls); recipients were monitored for transfusion reactions.

RESULTS

In 12/21 dogs a positive cross-match (microscopic degree of agglutination [AD] 1+ to 2+) was observed within 4 days after the transfusion. In a nonlinear regression model, no significant association was detected between type of anemia (P = .41), RBC storage time (P = .44), immunosuppressive treatment (P = .75) nor transfusion volume (P = .70) and the occurrence of positive cross-matches within 4 days after transfusion. Another 4 dogs developed a positive cross-match (microscopic AD 1+ to 2+) after 6 to 13 days.

CONCLUSIONS AND CLINICAL IMPORTANCE

Because production of alloantibodies was detected as early as 1 day after transfusion, cross-matching should be performed before every subsequent transfusion.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) Transfusion Reaction Small Animal Consensus Statement (TRACS). Part 1: Definitions and clinical signs

OBJECTIVE

To use a systematic, evidence-based consensus process to develop definitions for transfusion reactions in dogs and cats.

DESIGN

Evidence evaluation of the literature was carried out for identified transfusion reaction types in dogs and cats. Reaction definitions were generated based on synthesis of human and veterinary literature. Consensus on the definitions was achieved through Delphi-style surveys. Draft recommendations were made available through industry specialty listservs and comments were incorporated.

RESULTS

Definitions with imputability criteria were developed for 14 types of transfusion reactions.

CONCLUSIONS

The evidence review and consensus process resulted in definitions that can be used to facilitate future veterinary transfusion reaction research.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) Transfusion Reaction Small Animal Consensus Statement (TRACS) Part 2: Prevention and monitoring

OBJECTIVE

To systematically review available evidence to develop guidelines for the prevention of transfusion reactions and monitoring of transfusion administration in dogs and cats.

DESIGN

Evidence evaluation of the literature (identified through Medline searches through Pubmed and Google Scholar searches) was carried out for identified transfusion reaction types in dogs and cats. Evidence was evaluated using PICO (Population, Intervention, Comparison, Outcome) questions generated for each reaction type. Evidence was categorized by level of evidence (LOE) and quality (Good, Fair, or Poor). Guidelines for prevention and monitoring were generated based on the synthesis of the evidence. Consensus on the final recommendations and a proposed transfusion administration monitoring form was achieved through Delphi-style surveys. Draft recommendations and the monitoring form were made available through veterinary specialty listservs and comments were incorporated.

RESULTS

Twenty-nine guidelines and a transfusion administration monitoring form were formulated from the evidence review with a high degree of consensus CONCLUSIONS: This systematic evidence evaluation process yielded recommended prevention and monitoring guidelines and a proposed transfusion administration form. However, significant knowledge gaps were identified, demonstrating the need for additional research in veterinary transfusion medicine.

Canine Blood Group Prevalence and Geographical Distribution around the World: An Updated Systematic Review

In recent years, blood transfusions have been more commonly given to pets. The importance of determining blood groups in dogs and cats is, therefore, well-known for reducing the risk of adverse reactions in the recipient blood caused by a "non-compatible" donor. This systematic review summarizes data from previously published reports and follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for systematic reviews. After applying the inclusion and exclusion criteria, we identified 41 eligible studies using different states and blood-typing methods to determine blood groups in dogs. The dog blood groups that were identified between 1999 and 2020 in 17 different countries were combined to yield the DEA (Dog Erythrocyte Antigen), Kai, and Dal groups. These studies were conducted in Europe, America, Africa, and Asia but not in all the countries of these continents. The methods used to determine blood types have also changed over the years. This systematic review highlights gaps in the literature and should advance future studies synthesizing data with methodological rigor.

Identification of 5 novel feline erythrocyte antigens based on the presence of naturally occurring alloantibodies

Background

Since the discovery of the Mik antigen, several studies have described blood incompatibilities unrelated to the AB system in cats.

Objective

To estimate the prevalence of cats with non‐AB incompatibilities associated with naturally occurring alloantibodies (NOAb), and to begin mapping the corresponding feline erythrocyte antigens (FEA).

Animals

Two hundred and fifty‐eight type A cats.

Methods

Prospectively, cats were evaluated for the presence of NOAb by crossmatching in groups of 4‐6 cats. When NOAb were detected in a cat, its plasma was used as reagent to assess for the presence of the corresponding FEA in all cats included thereafter, and agreement observed between results of this extensive blood typing was evaluated.

Results

The chance of detecting incompatibilities by randomly crossmatching 2 cats was 3.9%, which resulted in at least 7% of type A cats having NOAb. Blood typing and agreement analyses performed with 7 newly detected NOAb allowed the identification of 5 presumably distinct FEA. Feline erythrocyte antigens 1 and 5 were most frequent with prevalence of 84% and 96%, respectively. Only FEA 1‐negative status was associated with a higher risk of presenting NOAb; with 16.7% of 42 FEA 1‐negative cats having NOAb compared to 5.1% of 216 FEA 1‐positive cats.

Conclusions and Clinical Importance

This study represents a first step of FEA identification outside the AB system. Because of its prevalence and association with NOAb, FEA 1 might correspond to the Mik antigen.

Dal-induced red blood cell incompatibilities in a Doberman Pinscher with von Willebrand factor deficiency and ehrlichiosis

OBJECTIVE

To describe a complex case involving the management of a dog with von Willebrand disease (vWD), active ehrlichiosis infection, nonregenerative anemia, and blood type incompatibility related to the Dal antigen.

CASE SUMMARY

A 13-week-oldintact male Doberman Pinscher weighing 7.2 kg was presented to the emergency service for a previous hemorrhaging event and progressive nonregenerative anemia. The dog had received a fresh whole blood transfusion 8 days prior to presentation due to severe anemia. Upon presentation, the puppy was tachycardic, and his mucous membranes were pale. A CBC revealed a nonregenerative anemia with a PCV of 0.11 L/L (11%). von Willebrand factor deficiency was suspected and later confirmed. The dog's blood type was dog erythrocyte antigen (DEA) 1 positive, but cross-matching to 4 RBC units, both DEA 1 positive and negative, failed to yield any compatible units. Antibody against a possible Dal RBC antigen was suspected, and 11 blood donors (Dalmatians and Dobermans) were cross-matched to find 2 compatible donors. After an uneventful fresh whole blood transfusion, a bone marrow biopsy revealed a hypocellular bone marrow and erythroid hypoplasia. A SNAP4DxPlus test and subsequent polymerase chain reaction (PCR) testing were positive for Ehrlichia ewingii and E. canis. Treatment with doxycycline was started, and the PCV was 0.17 L/L (17%) at discharge. At the 1-week follow-up, the PCV was 0.24 L/L (24%), and the puppy was doing well.

NEW OR UNIQUE INFORMATION PROVIDED

This is a unique case of a dog presenting with several challenging disorders, including vWD resulting in hemorrhage, ehrlichiosis potentially contributing to a nonregenerative anemia, and a blood type incompatibility due to the Dal antigen. Doberman Pinschers have a high prevalence of vWD- and Dal-negative phenotype, which emphasizes the value of cross-matching and the recognition of antigen prevalence in specific breeds.

Prevalence of Dal blood type and dog erythrocyte antigens (DEA) 1, 4, and 7 in canine blood donors in Italy and Spain

BACKGROUND

The aim of this study was to determine the prevalence of Dal, and DEA 1, 4, 7 blood types, in a population of canine blood donors from Italy and Spain. Three hundred and twenty blood donor dogs receiving an annual health evaluation were included in the study. DEA 1 blood type was determined using an immunochromatographic strip technique while Dal, DEA 4 and 7 blood types were determined with polyclonal antisera using agglutination on gel columns.

RESULTS

Out of 320 dogs blood typed 7 (2 Cane Corso and 5 Doberman Pinschers) (2.2%) were Dal negative; 137 (42.8%) were positive for DEA 1; 320 (100%) were positive for DEA 4 and 43 (13.4%) were positive for DEA 7.

CONCLUSION

This study showed a similar prevalence of DEA 1, 7 and 4 to that reported in previous studies in the same, and in different, geographic areas, and provides new data on the prevalence of the Dal blood group in Italy and Spain. There was no significant difference (P = 0.8409) between prevalence of Dal negative blood types found in our population (2.2%) and the prevalence reported in a canine blood donor population from the USA (2.5%). Our study identified Dal negative dogs in a previously tested breed i.e. Doberman Pinschers, but also the Cane Corso breed was found to have Dal negative dogs.

Survey of Blood Groups DEA 1, DEA 4, DEA 5, Dal, and Kai 1/Kai 2 in Different Canine Breeds From a Diagnostic Laboratory in Germany

More than twelve blood group systems have been described in dogs, but little is known about their distribution frequencies within breed populations. Here, we report on an extensive typing survey carried out using available reagents and either established or new clinical kits in purebred dogs from Germany. Leftover anticoagulated blood samples were examined using an immunochromatographic strip method for DEA 1, a gel column technique for Dal and Kai 1/2, and new card agglutination tests for DEA 4 and DEA 5 (which were partially compared with the gel column technique). Monoclonal antibodies were used for DEA 1 and Kai 1/2 typing, and polyclonal antibodies were used for all other types. Among the 206 dogs, 59.2% were DEA 1+, 100% DEA 4+, 9% (Card)/11% (Gel) DEA 5+, 89.3% Dal+, 96.6% Kai 1+, and 2.9% Kai 2+. None of the dogs were Kai 1+/2+, and only one was Kai 1-/2-. Dal- dogs were found in several breeds. Erythrocytes from most DEA 1+ dogs bound strongly on the strips. The agglutination reactions for DEA 5 on the new card tests were generally less than those on the gel column. The blood group pattern DEA 4+, DEA 5-, Dal+, Kai 1+/2- and either DEA 1+ or DEA 1- was found among 80% of the dogs. In this first extensive blood typing survey of purebred dogs from Europe, the proportions of positive and negative blood types were similar to those found in the United States and, for DEA 1, were also similar to those from other European countries, with considerable breed variation in blood types. The newer typing techniques seem to work well and will likely be useful for detecting and preventing specific blood type incompatibilities in the clinic.

Comparison of cross-matching method for detection of DEA 7 blood incompatibility

We compared 3 major cross-match (XM) tests to identify dog erythrocyte antigen (DEA) 7 blood incompatibilities in dogs as a result of anti-DEA 7 antibodies: gel (GEL), standard tube (TUBE) agglutination, and immunochromatography strips (STRIP). Blood samples from 42 dogs were typed for DEA 7; 2 tested DEA 7-positive (DEA 7+). The 40 DEA 7-negative (DEA 7-) plasma samples were cross-matched against the 2 DEA 7+ and 3 DEA 7- red blood cell (RBC) samples by GEL to identify samples with anti-DEA 7 antibodies. Twenty DEA 7- plasma samples without and with anti-DEA 7 antibodies were cross-matched with samples of the 2 DEA 7+ RBCs in a double-blind fashion using the TUBE and STRIP XM methods. GEL results were used as the reference method for comparison. To determine relationships between results, 2 × 2 tables were used. Cohen kappa coefficient (κ) was calculated between results of GEL and the other 2 methods. With GEL, 21 of 40 XM tests were positive and 19 of 40 negative for anti-DEA 7 antibodies. The same results were obtained by TUBE, whereas only 1 of 40 XM tests was positive by STRIP. There was a statistically significant relationship between results of GEL and TUBE ( p < 0.000) with perfect agreement (κ = 1.000), but not between GEL and STRIP results ( p = 1.000) in which agreement was equivalent to chance (κ = 0.0453). The GEL and TUBE XM tests, but not STRIP, are useful methods for identification of DEA 7 incompatibilities caused by anti-DEA 7 antibodies.

Frequency of DEA 1 antigen in 1037 mongrel and PUREBREED dogs in ITALY

Background

The prevalence of dog erythrocyte antigen (DEA 1) in canine population is approximately 40–60%. Often data are limited to a small number of breeds and/or dogs. The aims of this study were to evaluate frequency of DEA 1 in a large population of purebred and mongrel dogs including Italian native breeds and to recognize a possible association between DEA 1 and breed, sex, and genetic and phenotypical/functional classifications of breeds. Frequencies of DEA 1 blood group collected from screened/enrolled blood donors and from healthy and sick dogs were retrospectively evaluated. The breed and the sex were recorded when available. DEA 1 blood typing was assessed by immunocromatographic test on K3EDTA blood samples. The prevalence of DEA 1 antigen was statistically related to breed, gender, Fédération Cynologique Internationale (FCI) and genotypic grouping.

Results

Sixty-two per cent dogs resulted DEA 1+ and 38% DEA 1-. DEA 1- was statistically associated with Dogo Argentino, Dobermann, German Shepherd, Boxer, Corso dogs, the molossian dogs, the FCI group 1, 2 and 3 and the genetic groups “working dogs” and “mastiff”. DEA 1+ was statistically associated with Rottweiler, Briquet Griffon Vendéen, Bernese mountain dog, Golden Retriever, the hunting breeds, the FCI group 4, 6, 7 and 8 and the genetic groups “scent hounds” and “retrievers”. No gender association was observed.

Conclusions

Data obtained by this work may be clinically useful to drive blood donor enrollment and selection among different breeds.

Kai 1 and Kai 2: Characterization of these dog erythrocyte antigens by monoclonal antibodies

Dog Erythrocyte Antigens (DEA) have thus far been found by sensitizing dogs with canine allogeneic blood and are clinically important regarding blood transfusion incompatibilities, but remain poorly defined. The goals of this study were to discover and characterize two DEAs, named as Kai 1 and Kai 2. The monoclonal antibodies were produced by mouse hybridoma techniques and examined by ELISA isotyping, immunoblotting, and affinity chromatography. Canine blood samples were typed and the development of alloantibodies was examined in transfused dogs. The monoclonal Kai 1 and Kai 2 antibodies were isotyped as IgM kappa and IgG3 lamda, respectively, and identified two different erythrocyte membrane proteins of 200 kDa and 80 kDa in molecular weights, respectively. Either Kai 1 or Kai 2 can be expressed but not both in an individual dog. There were no naturally occurring anti-Kai 1 or Kai 2 alloantibodies. In addition, Kai 1- and/or Kai 2- dogs developed Kai 1 and Kai 2 alloantibodies, respectively, when transfused with mismatched blood. This is the first discovery of canine blood types by screening monoclonal antibodies. Kai 1 and Kai 2 are novel blood types which can induce anti-Kai 1 or anti-Kai 2 alloantibodies when Kai 1- and/or Kai 2- dogs are transfused with Kai 1+ or Kai 2+ blood. These canine blood types may explain some of the blood incompatibilities and transfusion reactions observed in dogs in clinical practice.

Prevalence and Mode of Inheritance of the Dal Blood Group in Dogs in North America

Background

The Dal blood group system was identified a decade ago by the accidental sensitization of a Dal− Dalmatian with a Dal+ blood transfusion. Similar Dal‐related blood incompatibilities have been suspected in other Dalmatians, Doberman Pinschers, and other breeds.

Objectives

To determine the prevalence and mode of inheritance of the Dal antigen expression in dogs.

Animals

A total of 1130 dogs including 128 Dalmatians, 432 Doberman Pinschers, 21 Shih Tzus, and 549 dogs of other breeds including 228 blood donors were recruited from North America between 2008 and 2015.

Methods

Prospectively, dogs were blood typed for Dal applying a gel column technique using polyclonal canine anti‐Dal sera. Pedigrees from 8 typed families were analyzed.

Results

The prevalence of the Dal+ blood type varied between 85.6 and 100% in Dalmatians and 43.3–78.6% in Doberman Pinschers depending on geographical area. Dal− dogs were identified mostly in Dalmatians (15/128; 11.7%), Doberman Pinschers (183/432; 42.4%), and Shih Tzus (12/21; 57.1%), and sporadically in mixed‐breed dogs (3/122; 2.5%), Lhasa Apsos (1/6) and Bichon Frises (1/3). Only 6/245 (2.4%) blood donors were found to be Dal−, including 5 Doberman Pinschers. The mode of inheritance of the Dal+ phenotype was determined to be autosomal dominant.

Conclusions and Clinical Importance

The high percentage of Dal− Doberman Pinchers, Dalmatians and Shih Tzus increases their risk of being sensitized by a blood transfusion from the common Dal+ donor. Extended Dal typing is recommended in those breeds and in dogs when blood incompatibility problems arise after initial transfusions.