Comparison of Tube, Gel, and Immunochromatographic Strip Methods for Evaluation of Blood Transfusion Compatibility in Horses

Monitoring the positive conversion of anti-erythrocyte antibodies in blood transfusion donor horses

To confirm the positive conversion of antibodies against erythrocyte antigens in horses, possible blood transfusion donor horses selected from draft horse populations were periodically monitored with an indirect antiglobulin (Coombs) test for approximately 3 years. In this study, 19 horses (16 females and 3 males) were investigated, and five mares showed alloantibodies during the monitoring period. Four mares were typically pregnant when positive conversion was detected, whereas no particular cause of conversion could be observed for one mare based on its clinical records. In the analyzed horses, most positive conversions were possibly due to pregnancy, as conversion occurred more often during this period than after parturition. Pregnancy is considered a key event for positive conversion. Additionally, in cases in which unknown causative sensitization is confirmed, continuous monitoring with a test to detect antibodies should be performed, even if the possible donor is selected and maintained.

Blood types and antibody profiles of Straight Egyptian Arabian horses in Qatar: Preliminary results

The characterization of the blood groups, antibody profiles, and its distribution pattern among different horse breeds and geographic locations, can be very useful in life-threatening situations where a blood transfusion is needed, and compatibility tests are not readily available. This study estimated the distribution of blood types and antibody profiles in Straight Egyptian Arabian horses from Qatar. A total of 20 Straight Egyptian Arabian horses, from multiple origins and genetic background were included. Venous blood from each horse was typed and screened for anti-red blood cell (RBC) hemolytic and agglutinating antibodies. Descriptive statistical analysis and Fisher Exact test were applied, considering 95% confidence interval (95% CI). All included horses (100%) had Aa and Ca blood types (95% CI: 83.2%-100.0%). Other blood types found less frequently included Ua (50%), Qc (45%), Pa (40%), Qb (25%) and Qa (5%). Only horses with travel history developed anti-RBC antibodies (6 out of 9), however, no horse carried more than one type of anti-RBC antibodies, supporting the premise that environmental factors may influence the development of alloantibodies. Although pre-transfusion testing regardless the circumstances should be prioritized, even considering a small population of horses, our findings suggest that Straight Egyptian Arabian horses in Qatar could be safely used as blood donors, due to the apparent omnivalence of Aa and Ca blood types and lower incidence of alloantibodies, important in emergency situations where pre-transfusion testing is unavailable.

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.

Collection and administration of blood products in horses: Transfusion indications, materials, methods, complications, donor selection, and blood testing

BACKGROUND

Blood transfusion is a lifesaving treatment for horses with acute hemorrhage and other causes of anemia. Transfusions improve oxygen delivery to the tissues via increased blood volume and hemoglobin concentration. Certain aspects of equine blood transfusion are challenging, especially in the field situation, and practitioners may be unfamiliar or feel overwhelmed with the process. An understanding of the indications, materials, methods, and techniques as well as donor selection and possible complications will help practitioners successfully implement blood transfusion in clinical practice.

PROCEDURES

Blood transfusion involves several steps including appropriate donor selection, cross-matching, blood collection, and administration, as well as monitoring and handling of transfusion reactions. Guidance for each of these steps are detailed in this review.

SUMMARY

Blood transfusion is an effective and often lifesaving treatment for managing diseases of blood loss, hemolysis, and decreased RBC production. Equine practitioners require a thorough understanding of the indications for blood transfusion, the immunological principles behind compatibility testing and transfusion reactions, and the technical skills to aseptically collect and administer blood products KEY POINTS: Equine practitioners require a thorough understanding of the indications for blood transfusion, the immunological principles behind compatibility testing and transfusion reactions, and the technical skills to aseptically collect and administer blood products. Because there are over 400,000 possible equine RBC phenotypes, no universal donor exists, and some blood type incompatibilities are likely between any donor and recipient. Therefore, prior to any blood transfusion, donor and recipient blood should be cross-matched Inadequate delivery of oxygen (Do₂ ) to the tissues, resulting from low hemoglobin (Hb) concentration, is the most important indication for blood transfusion Neonatal isoerythrolysis most commonly occurs following an anamnestic response in late gestation; it rarely occurs following a primary exposure because the immune response is not strong enough to produce clinically significant alloantibody titers.

Investigation of erythrocyte antigen frequencies in draft horse populations in Japan to assess blood donor suitability

Erythrocyte alloantigen frequencies of draft horses in Japan were investigated to assess blood donor suitability for transfusion. Here, 148 Japanese draft, 69 Percheron, and 65 Breton horses were blood-typed and subjected to an indirect antiglobulin test. Regarding the major immunogenic factors, the rates of Aa- and Qa-negative horses ranged from 0.35 to 0.49 and from 0.82 to 1.00, respectively. The rate of alloantibody-positive horses ranged from 0.12 to 0.35. Although the prevalence of alloantibodies in these horses was higher than that expected naturally, the rates of Aa- and Qa-negative horses were higher than those of some breeds reported previously. The current draft horse population could provide potential candidates for donors, and the obtained information may contribute to the selection of a safe donor for transfusion.

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.

Prevalence of Ca Blood Type and Alloantibodies in a Population of Horses from Italy

Simple Summary

Indications for whole blood transfusion in equine critical care include severe anemia from surgical blood loss or acute hemorrhage, hemolysis and neonatal isoerythrolysis. In horses, as in other animals, transfusions are associated with a number of inherent risks such as transfusion reactions. Pretransfusion screening and blood typing are indicated to minimize the risk of incompatible red cell transfusions. Equine blood types include seven systems, namely A, C, D, K, P, Q, and U. The major RBC antigens that warrant identification before packed RBC or whole blood transfusions in horses are Ca and Aa. The frequencies of blood groups can vary from one population to another and from one breed to another. In some situations where testing compatibility is not possible, such as in rural practice, the knowledge of the breed blood type frequencies may help selecting the best donor candidate. The aims of this study were to: estimate the prevalence of Ca blood type in horses from northern Italy; estimate the association between Ca blood type sex and breed of horse; estimate the prevalence of anti-Ca alloantibodies in Ca− horses. The prevalence of the Ca+ blood type was 79.1%. No significant association was found between blood type Ca and sex. The total number of Ca− samples with detectable anti-Ca alloantibodies was 7/23 (30.4%).

Abstract

A knowledge of the blood groups and alloantibodies present is essential for the safe transfusion of blood products in horses. Pre-transfusion screening and blood typing minimizes the risk of incompatible RBC transfusions and prevents immunization of the recipient against incompatible RBC antigens. The frequencies of blood groups can vary among different breeds. Knowledge of a breed’s blood group prevalence can be very useful for identifying the best blood donors during transfusion in clinical practice. The aims of this study were to estimate the prevalence of the Ca blood type in horses from Italy using a monoclonal immunocromatographic method and to estimate the prevalence of anti-Ca alloantibodies in Ca− horses using agglutination on gel technique. Ca blood type was determined on 110 whole blood samples. The prevalence of the Ca+ blood type was 79.1%. This study also provides data about the prevalence of Ca+ blood group in Italian Saddle Horses (77,3%) and Dutch Warmblood (58,3%). No significant association was found between Ca blood type and sex with 79.5% and 78.8% of females and males testing Ca+, respectively. The total number of Ca− samples with detectable anti-Ca alloantibodies was 7/23 (30.4%).

Agreement of stall-side and laboratory major crossmatch tests with the reference standard method in horses

Background

Crossmatching is used to prevent life‐threatening transfusion reactions in horses. Laboratory methods are laborious and technically challenging, which is impractical during emergencies.

Hypothesis/Objectives

Evaluate agreement between a stall‐side crossmatch kit (KIT) and a laboratory method (LAB) in horses with known and unknown blood types.

Animals

Twenty‐four blood‐typed and alloantibody‐screened healthy adult horses (Aim 1) and 156 adult horses of unknown blood type (Aim 2).

Methods

Prospective, blinded study. Expected positive (n = 35) and negative (n = 36) crossmatches among 24 antibody and blood‐typed horses were used to determine sensitivity and specificity of KIT and LAB against the reference method. Agreement in 156 untyped horses was evaluated by reciprocal crossmatch (n = 156).

Results

Sensitivity (95% confidence interval [CI]) for LAB and KIT compared with expected reactions was 77.1% (59.9%‐90.0%) and 91.4% (77.0%‐98.2%), and specificity 77.8% (60.9%‐89.9%) and 73.5% (55.6%‐87.1%), respectively. The KIT was 100% sensitive for Aa reactions; LAB was 100% sensitive for Qab; and both were 100% sensitive for Ca. Cohen's κ agreement for LAB and KIT with expected positive and negative reactions (n = 71) was moderate (0.55 [0.36‐0.74]) and substantial (0.65 [0.47‐0.82]), respectively. Agreement was fair comparing LAB with KIT in Aim 1 (0.30 [0.08‐0.52]) and in untyped horses in Aim 2 (0.26 [0.11‐0.41]).

Conclusions and Clinical Importance

Agreement between KIT and LAB with expected reactions was blood type dependent. Performance of both methods depends on blood type prevalence.

Modified stall-side crossmatch for transfusions in horses

Background

After‐hours or out‐of‐clinic crossmatches are often limited by the lack of access to specialized material and technical expertise.

Hypothesis/Objectives

The goal was to adapt a stall‐side crossmatch test for pretransfusion evaluation in horses.

Animals

Twelve healthy mares (plasma and blood donors, teaching mares).

Methods

In a prospective study, blood from 12 mares was used to compare the results of 132 crossmatches performed with a rapid gel assay to crossmatches performed with a microgel column assay, and with predicted compatibilities based on blood types and detection of antibodies at a reference laboratory (microplate assay). The rapid gel assay protocol for dogs was adapted to decrease the formation of rouleaux that initially precluded equine erythrocytes migration through the gel.

Results

There was a good agreement between the rapid gel assay and the microgel assay as well as with the predicted compatibilities (κ > .6 for both). Agreement was higher between the microgel assay and the predicted compatibilities (κ = .8). The rapid gel assay failed to detect 6 predicted Aa incompatibilities (agglutinins‐related), 3 of which were also not detected with the microgel assay.

Conclusions and Clinical Importance

Based on these results, the modified rapid gel assay could be useful in settings when access to the microgel assay is not available. Discrepancies between both gel techniques and predicted compatibilities were most often low‐grade agglutination, which warrants further investigation to assess their clinical importance.

Prevalence of naturally occurring non-AB blood type incompatibilities in cats and influence of crossmatch on transfusion outcomes

BACKGROUND

Recognition of the feline red blood cell (RBC) antigen Mik and the presence of naturally occurring anti-Mik antibodies resulting in acute hemolytic transfusion reactions prompted the recommendation to perform a crossmatch before a cat's first RBC transfusion, but this guideline has not yet become a standard practice.

OBJECTIVE

To determine the prevalence of naturally occurring non-AB alloantibodies detectable by tube crossmatch, and to compare transfusion outcomes in cats with and without a crossmatch performed.

ANIMALS

Three hundred cats that received an RBC transfusion, with or without a major crossmatch performed.

METHODS

Retrospective study.

RESULTS

Major crossmatch incompatibilities were documented in 23 of 154 transfusion-naive cats (14.9%) and in 15 of 55 previously transfused cats (27%; P = 0.042). Type-specific packed RBCs (pRBCs) were administered to 167 and 82 cats with and without a crossmatch, respectively. Median volume of pRBCs administered during the first transfusion was 5.3 mL/kg (range, 2.4-18 mL/kg). Median change in PCV scaled to dose of pRBCs was +0.8%/mL/kg; administration of crossmatch-compatible pRBCs was not associated with a greater increase in PCV. Febrile transfusion reactions occurred more often in cats that received non-crossmatched (10.1%) compared to crossmatched (2.5%) pRBCs (P = 0.022). Seventy-six percent of cats that received pRBC transfusions survived to hospital discharge. A crossmatch was not associated with improved survival to discharge or at 30 or 60 days posttransfusion.

CONCLUSIONS AND CLINICAL IMPORTANCE

The prevalence of naturally occurring non-AB incompatibilities is sufficiently high to justify the recommendation to perform a crossmatch before all (including the first) RBC transfusions in cats.

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.

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.