Reliability of 400‐cell and 5‐field leukocyte differential counts for equine bronchoalveolar lavage fluid

Abstract

Enumeration of mast cells is unreliable when the standard 400-cell differential counting method is used, whereas the 5-field method on slides with higher cell density reached acceptable reproducibility. Neutrophil percentages were highly reliable with both methods.

Inflammatory Airway Disease of Horses—Revised Consensus Statement

“…Cytological variations associated with volume of fluid instilled, site of sampling, selection of aliquot, sample preparation and cell‐counting method64, 73, 74, 75, 76, 77, 78, 79 preclude the use of definitive cut‐off values for the classification of IAD. However, based on published studies that used 250‐mL infusion volume, reference values for BALF cytology in healthy controls were: total nucleated cell count ≤530 cells/μL, neutrophils ≤5%, eosinophils ≤1%, and metachromatic cells ≤2%.…”

Recurrent respiratory disorders in Polish Konik horses - clinical and laboratory findings

“…Fluid obtained from healthy horses contains 60% of macrophages, 35% of lymphocytes, <5% of neutrophils, and <2% of mast cells (19). Whereas, BALF obtained from RAO-affected horses contains 50%-85% of nondegenerated segmented neutrophils (3,4). Result obtained in the study group (almost 60% of nondegenerated neutrophils) clearly demonstrates RAO as a direct cause of chronic respiratory problem.…”

“…The samples containing 1 mL of the fluid were concentrated by cytospin and stained with Wright's stain. Following staining, the percentage of macrophages, neutrophils, lymphocytes, eosinophils, and mast cells was determined by counting 400 cells (4).…”

Equine Recurrent Airway Obstruction

“…In cytological preparations made from the fl uid, the largest group of cells are non-degenerated neutrophils (15-85% of all cells), whereas in healthy horses there are no more than 10% (6). There are also a number of compact formations of bronchial mucus (Curschmann's spirals).…”