You are here: The Avian Differential


The purpose of this teaching module is to provide an in-depth study of the avian differential, including blood collection and handling methods, staining techniques and cell morphology.  The study of avian hematology is a challenging subject in a field that is growing rapidly.   With the popularity of pet birds comes an increase in the number of avian patients presented for veterinary care.  Diagnostics, including hematology, are an integral part of this care.  It is critical for veterinary technicians to become proficient at performing hematologic evaluations.

Modern technology has not yet developed a method for using automated cell counters for evaluating leukocyte differentials, due to the inability of cell counters to separate avian leukocytes from nucleated erythrocytes and thrombocytes.  In addition, there are slight interspecies differences in the appearance of some cell lines, such as eosinophils.   Consequently, avian medicine relies upon the manual identification of avian blood cells by veterinary laboratory technicians.

The three subtopics within this module are intended as guides to acquaint faculty, working professionals or student veterinary technicians with a method of performing a manual avian differential. This hematological test is crucial to diagnosing the health status of an avian patient. Safe amounts for blood withdrawal and the location of collection sites are covered.  Proper methods of slide preparation and staining—which should lead to more accurate differential results—are discussed.

Teaching and Learning Methodology

This module is designed so it can apply to various modes of learning delivery methods. The student or instructor can use the learning activities in the module as support to a course delivered by traditional methods via a classroom setting, a stand alone online internet course, computer-assisted instruction course or with additional material as part of traditional curriculum in a degree or continuing education laboratory technology training program. Delivery method for this module can be adapted to accommodate face-to-face, online or a combination of methods customized to the individual learner or situation. Activities and resources in the module can be used to address multiple learning styles for the adult student learner. Assessment activities are varied and are flexible enough to adapt to multiple applications in the use of this module.