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

Abstract

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.