Accuracy of point‐of‐care crossmatching methods and crossmatch incompatibility in critically ill dogs

Abstract

Background: The performance of commercial point-of-care crossmatch (CM) tests compared to laboratory tube agglutination CM is unknown. Additionally, there is limited information regarding CM incompatibility in ill dogs. Objectives: To determine if point-of-care major CM methods are accurate in detecting compatible and incompatible tests when compared to laboratory CM methods, and to identify factors associated with CM incompatibility in dogs. Animals: Part 1 (prospective) included 63 client-owned dogs potentially requiring blood transfusion. Part 2 (retrospective) included all dogs from part 1, plus medical records of 141 dogs with major CM results. Methods: For part 1, major CM was performed using a tube agglutination assay (LAB-CM), a gel-based point-of-care test (GEL-CM), and an immunochromatographic point-of-care test (IC-CM). For part 2, medical record data were collected to determine rates of and risk factors for CM incompatibility. Results: Kappa agreement between the LAB-CM and GEL-CM methods could not be calculated due to a relative lack of incompatible results. Kappa agreement between the LAB-CM and IC-CM methods was 0.16 (95% confidence interval [CI] = 0-0.31, P = .007) indicating no agreement. The LAB-CM incompatibility in transfusion-naïve vs dogs that had a transfusion was 25% and 35%, (P = .3). Conclusions and Clinical Importance: Compared to laboratory methods, point-ofcare methods evaluated in our study lacked sensitivity for detecting incompatibilities. Dogs had similar rates of major CM incompatibility regardless of transfusion history. This suggests CM testing prior to transfusion be considered in all dogs however our study did not investigate clinical relevancy of incompatible LAB-CM.

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

“…85,90,94 As mentioned previously, variation in crossmatch technique complicates evaluation of the existence and clinical relevance of those alloantibodies in dogs. 93,[98][99][100]105 3.6.4…”

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

“…This is often referred to as the gold standard, but it has also been suggested that this method is too sensitive and identifies also clinically irrelevant incompatibilities. 53 The addition of antiglobulins might even has enhanced the agglutination reaction. 53,54 Therefore, it is uncertain whether this increases the sensitivity in detecting clinically relevant or irrelevant antibodies.…”

Comparison of a commercial immunochromatographic strip crossmatch kit and standard laboratory crossmatch methods for blood transfusion compatibility in dogs

“…Recent studies utilizing a similar SL technique yielded incompatibility rates of only 17%–38% for major crossmatches and 17%–45% for minor crossmatches. The institutional rates were higher than historical SL rates, even when previous transfusion status was taken into account 6,9–10,20 . Therefore, we wished to investigate this discrepancy of the SL test performed at the authors’ institution to another SL technique performed at a commercial laboratory.…”

“…Many practitioners choose not to crossmatch transfusion‐naïve dogs due to the clinical observation that dogs lack clinically significant alloantibodies prior to initial transfusion. However, ongoing discoveries of new canine RBC antigens have led some to recommend crossmatching prior to all transfusions 4,9,19–20 . While many studies explore the compatibility results of various crossmatch tests in vitro, to the authors’ knowledge the sensitivity/specificity of these tests to predict clinically relevant transfusion reactions is unknown 6,9,15 …”

“…However, ongoing discoveries of new canine RBC antigens have led some to recommend crossmatching prior to all transfusions. 4,9,[19][20] While many studies explore the compatibility results of various crossmatch tests in vitro, to the authors' knowledge the sensitivity/specificity of these tests to predict clinically relevant transfusion reactions is unknown. 6,9,15 A preliminary retrospective review of the authors' institutional SL crossmatch data (SL-I) found considerably more incompatible major crossmatches in dogs (69%, unpublished data) compared to that reported in previous veterinary literature.…”