White blood cell count in birds: evaluation of a commercially available method

Abstract

BackgroundTo conduct a hematological analysis of avian blood samples, standard automated cell counting is unreliable because all avian blood cells are nucleated. Therefore, quantitative white blood cell counting in birds is still performed manually, whereby the Natt-Herrick method is widely used in veterinary laboratories. The aim of this study was to evaluate a new commercially available single test system for avian white blood cell counting, the Natt-Herricks-Tic®, which would allow easy in-house analysis by clinicians or technicians. A total of 40 avian ethylenediaminetetraacetic acid (EDTA) blood samples from 24 different species were included in the study. To assess method agreement, each blood sample was analyzed for total white blood cell count with the test method and the Natt-Herrick reference method. To determine the imprecision of the reference method and the Natt-Herricks-Tic® method, the noncorrected white blood cell count was determined ten consecutive times from one avian EDTA blood sample for each method.ResultsThe Natt-Herricks-Tic® method performed well concerning staining quality and countability of the granulocytes by the hemocytometer. In the agreement study, the Natt-Herricks-Tic® method showed a small proportional systematic error with a small positive mean bias of 282 white blood cells/μL but had wide 95% limits of agreement (− 4683 cells/μL to 5227 cells/μL), indicating random error. The precision study resulted in a coefficient of variation of 16% for the Natt-Herricks-Tic® method (the mean ± standard deviation: 9.7 × 103/μL ± 1.5 × 103/μL) and 23% (the mean ± standard deviation: 7.9 × 103/μL ± 1.8 × 103/μL) for the reference method.ConclusionsThe Natt-Herricks-Tic® method showed acceptable precision for a manual method and demonstrated good agreement with the reference method. It can be recommended as a reliable and suitable method for determining white blood cell counts in avian EDTA blood if nonstatistical quality control measures are used in the daily routine. The application of individual reference intervals for the interpretation of white blood cell counts in birds may improve the diagnostic performance of this important analyte in a clinical setting.

The effect of methionine and folic acid administered in ovo on the hematological parameters of chickens (Gallus gallus domesticus)

“…The ease of sample collection makes blood tests one of the basic diagnostic tools in both human and veterinary medicine ( Talebi et al., 2005 ; Mitchell and Johns, 2008 ; Merska et al., 2013 ; Carisch et al., 2019 ). However, in practice, hematological tests are more rarely performed on avians than on mammals, mainly owing to the high labor intensity that is a result of the specificity of the blood cell structure and the absence of generally accepted reference values ( Talebi et al., 2005 ; Keshavarz et al., 2019 ; Stefaniak et al., 2019 ).…”

Effect of Low Dose Gamma Irradiation on Number and Ratio of Some Peripheral Blood Cells in Hatched Chicks

“…The standard automated cell counting is not an acceptable method for blood analysis in birds due to the specific morphological structure of avian blood cells, i.e., nucleated red blood cells and platelets. Despite major disadvantages and limitations, the manual blood cell counting technique is still the best available method of avian blood analysis (Carisch et al, 2019). Several studies confirmed large variations in the manual blood counts; reported coefficients of variation are between 20 and 40% (Har et al, 2005;Weiss and Wardrop, 2010).…”

“…Several studies confirmed large variations in the manual blood counts; reported coefficients of variation are between 20 and 40% (Har et al, 2005;Weiss and Wardrop, 2010). A disadvantage of Natt-Herrick solution is the difficulty to differentiate thrombocytes from lymphocytes, thus creating significant counting errors (Carisch et al, 2019). In order to improve the accuracy of cell counting, several methods were used, namely, an experienced operator, same brand of properly cleaned instrumentation and material, uniform distribution of cells in the observation area, more fields and cells counted and obtaining the results from at least 3 repetitions (Walberg, 2001).…”

Saccharomyces cerevisiae, bentonite, and kaolin as adsorbents for reducing the adverse impacts of mycotoxin contaminated feed on broiler histopathology and hemato-biochemical changes

“…The packed cell volume (PCV) was determined using the Microhematocrit method while the red blood cell (RBC) count and total white blood cell (WBC) count were determined using the hemocytometer method [35]. Hemoglobin (Hb) concentration was determined using Drabkin's reagent assay method for Hb concentration.…”