The effects of time and anticoagulant type on hematologic values in cockatiels (Nymphicus hollandicus)

Background

Avian hematologic characteristics complicate evaluation; therefore, complete blood cell counts require manual analysis for best accuracy. Furthermore, the quality of samples may be affected by prolonged shipment.

Methods

Blood was collected from the right jugular vein of twenty-four, 7-year-old (14 male, 10 female), wild-type cockatiels (Nymphicus hollandicus). Smears were prepared using fresh, untreated blood. The remainder was divided into dipotassium ethylenediaminetetraacetic acid (EDTA) and lithium heparin microtainers. A hematocrit tube and blood smear were prepared at baseline, 24, 48, and 72 hours after venipuncture. Packed cell volume (PCV), total solids (TS), estimated white blood cell (WBC) count, WBC differential (heterophils, lymphocytes, monocytes, eosinophils, basophils), hemolysis index (HI), and preparation quality were assessed and compared to baseline. After log transformation, the effects of anticoagulants across time points were compared.

Results

Heparinized samples had significant differences in WBC, heterophil, and lymphocyte counts at 48 hours, and PCV and TS at 72 hours compared to baseline. There was a positive proportional bias in PCV and TS from EDTA anticoagulant samples at 24, 48, and 72 hours, and from heparinized samples at 48 and 72 hours compared to baseline. The EDTA samples had increased PCV and TS compared to heparin at all time points, and higher WBC and heterophil counts at 48 hours compared to baseline. A type II methodological error cannot be excluded.

Conclusions and clinical relevance

These results suggest that the anticoagulant used and time spent in anticoagulant alters hematologic values in cockatiels, which may have significant clinical implications. The importance of sample processing within 24 hours and anticoagulant-specific reference intervals for hematologic variables should be considered.