Carolyn A. Sink’s research while affiliated with Virginia Tech and other places

Method validation studies characterize the performance of new laboratory methods relative to established methods using quality guidelines in order to define the new method's performance characteristics and to identify differences that could influence data interpretation. We investigated the performance of an in-clinic dry chemistry analyzer (Catalyst One, IDEXX) for measuring 19 routine plasma biochemistry analytes in dogs, cats, and horses. We analyzed 2 levels of quality control material (QCM) in duplicate twice daily for 5 d to determine the coefficient of variation (CV), percent bias, observed total error (TEobs), and sigma metric (σ) for each analyte at each level of QCM. We analyzed 82 canine, equine, and feline plasma samples with the in-clinic dry chemistry analyzer and a reference wet chemistry analyzer, and results were compared using correlation coefficients, Deming regression, and Bland-Altman analyses. CVs were <5% for 16 analytes and ⩾5% for 3 analytes. TEobs was less than allowable total error (TEa) for 9 analytes, and exceeded TEa for 10 analytes. Sigma metrics were >4 at both levels of QCM for 5 analytes, and at one level of QCM for 5 analytes; sigma metrics were <3 or could not be calculated at the remaining analyte concentrations. All analytes, except glucose, showed various magnitudes of bias compared to the wet chemistry analyzer. Based on these results, we recommend statistical (5 analytes) and non-statistical (14 analytes) QC measures and analyzer-specific reference intervals.

This chapter outlines the clinical signs and the associated physiologic mechanisms of transfusion reactions for the small animal practitioner. Febrile or allergic reactions may occur in the same manner as severe hemolytic reaction. For this reason, any change in the patient's condition during blood infusion should be considered a possible sign of adverse reaction and should be evaluated. Acute hemolytic transfusion reactions occur within 24 hours of a red cell transfusion. Primarily mediated by immunoglobulin G (IgG), they are antigen-antibody, type 2 hypersensitivity reactions and result in an abrupt hemolytic transfusion reaction with intravascular hemolysis. Since dogs lack clinically significant red cell alloantibodies, acute hemolytic transfusion reactions are primarily caused by sensitization from a previous blood transfusion. Delayed hemolytic transfusion reactions occur more than 24 hours after transfusion, with onset varying from 2 to 21 days. These reactions are often the result of an amnestic response to a red cell antigen that the recipient lacks.

The main goal of a blood bank or transfusion service is to provide a safe transfusion for every patient. Quality programs include quality control, quality assurance, and quality improvement, all of which ensure application of quality principles within operational areas. Examining issues related to quality assurance assist in setting high standards of patient care through constant improvement. The main purpose of the quality team is to identify and monitor quality indicators. A blood bank or transfusion service should maintain records pertaining to blood donors and blood recipients. Federal, state, and local guidelines should be consulted and followed for record storage time. Blood product inventory management is difficult since use of blood products can be unpredictable and erratic. It is beneficial to devise a plan for the management of blood products so that blood resource is used in a timely and efficient manner.

This chapter describes the most commonly used blood components in veterinary medicine. Fresh whole blood provides blood volume expansion and increased oxygen-carrying capacity to the recipient. Whole blood provides for volume expansion, increased oxygen-carrying capacity, protein source, and stable coagulation factors. Once fresh whole blood is stored at 1-6 °C for longer than 24 hours, it is classified as whole blood or stored whole blood. Red blood cells are used to treat anemia in normovolemic patients or pharmacologically untreatable anemia. To prepare this product, plasma is extracted from the unit of whole blood and the cells remaining in the bag are called red cells. Platelets stop hemorrhage as they are the first cellular element of the peripheral blood to react when blood vessels are damaged. Platelet concentrates or platelet-rich plasma are prepared immediately after blood collection using differential centrifugation. Leukocyte-reduced blood products have been shown to eliminate or attenuate adverse response to transfusion.

As blood transfusions are associated with certain risks, transfusion therapy should only be initiated when laboratory pre-transfusion testing is complete and the expected benefits of the transfusion outweigh the potential risks. In dogs, universal blood type means that the donor is negative for all dog erythrocyte antigen (DEA) types. Cats should always be blood typed prior to transfusion. For first time transfusion, a crossmatch is not required and type-specific blood can be dispensed. All transfusion therapy can produce only transient improvement in the patient's condition. Unless the patient is able to produce the deficit component endogenously, more transfusions will be necessary. Whole blood can be used during acute massive blood loss exceeding 20% of blood volume or coagulopathy with massive blood loss. The hematocrit will increase over the baseline value immediately after transfusion and increases further within 24 hours with volume redistribution. Any discrepancy should be resolved prior to beginning the transfusion.

Blood collection in dogs and cats necessitates careful planning to minimize potential donor reactions or contamination of the unit of blood. A tube stripper is used to push or “strip” blood from the donor tubing into the primary blood collection bag. Sealers are used to both contain the blood product and to impede contamination of the blood product. A vacuum, chamber, and scale can be used in feline blood collection, although vacuum pressure via syringe is the most popular phlebotomy method. Anticoagulants prevent blood from clotting, and blood collection systems utilize liquid solutions contained in the primary bag. Sodium citrate is the most commonly used anticoagulant; its action is to sequester calcium ions in vitro. Closed systems have integrally attached needles connected to satellite bags that contain anticoagulant-preservative-additive solutions. Using a closed blood collection system, sterility of the blood and blood products is not compromised during collection or processing into components for storage.

This chapter reviews blood typing methods and provides step-by-step procedures for compatibility testing and processing blood components. The “gold standard” of blood typing for dogs is detection of blood antigens by hemagglutination following incubation with polyclonal or monoclonal antibodies, while for cats the “gold standard” is the tube or microplate agglutination test. DMS Laboratories offers a card method to determine the blood type of cats. The assay is based on the agglutination reaction of red cells. Platelet-rich plasma (PRP) is made from one unit of fresh whole blood. To prepare PRP, a unit of fresh whole blood with at least one integrally attached satellite bag is needed. The blood product should be stored in an organized fashion. The product should be placed at appropriate storage temperature and documented as received in the product log. Blood products should be packaged and shipped in a manner that preserves product integrity.

Blood donors are vital to the success of any transfusion service, and veterinary blood banks depend on qualified donors to provide the blood necessary to meet the needs of the patients they serve. Good communication is imperative to the success of any blood donor program, and it is beneficial to define and communicate owner expectations during the blood donor qualification process. Every blood bank should establish appropriate laboratory testing to qualify blood donors into their donor program. Dog erythrocyte antigens and the prevalence of antibodies against specific dog erythrocyte antigens (DEA) antigens should be considered when selecting donors. Qualification of veterinary blood donors utilizing the criteria should be repeated at least annually and allows the clinician to evaluate physical exam and laboratory test findings in view of the overall goals of the blood donor program. Once donors are qualified into the blood donor program, it is necessary to track essential information regarding individual donors.

Knowledge of blood types, necessary equipment, blood type and crossmatch test procedures, and test interpretation are paramount in effective and safe transfusion medicine. A blood type and, in some instances, a crossmatch test should be performed prior to packed RBC (pRBC) or whole blood (WB) transfusions in dogs and cats. Blood typing and crossmatch procedures include a step to evaluate for the presence of autoagglutination. The dog erythrocyte antigen system (DEA), in which a number denotes the blood type, is the traditional schema used. Where blood typing identifies specific antigens on the RBC surface, a crossmatch test detects these alloantibodies against RBC antigen(s) present in the plasma or serum. In the event of a hemolytic transfusion reaction, collection of a pretransfusion recipient blood sample may also be useful for retrospectively evaluating pretransfusion recipient–donor compatibility. This is typically reserved for cases where a pretransfusion crossmatch test was not performed.

This study evaluated the quality and bacteriologic safety of platelet-rich plasma (PRP) produced by 3 simple, inexpensive tube centrifugation methods and a commercial system. Citrated equine blood collected from 26 normal horses was processed by 4 methods: blood collection tubes centrifuged at 1200 and 2000 × g, 50-mL conical tube, and a commercial system. White blood cell (WBC), red blood cell (RBC), and platelet counts and mean platelet volume (MPV) were determined for whole blood and PRP, and aerobic and anaerobic cultures were performed. Mean platelet concentrations ranged from 1.55- to 2.58-fold. The conical method yielded the most samples with platelet concentrations greater than 2.5-fold and within the clinically acceptable range of > 250 000 platelets/λL. White blood cell counts were lowest with the commercial system and unacceptably high with the blood collection tubes. The conical tube method may offer an economically feasible and comparatively safe alternative to commercial PRP production systems.