Abstract

Blood samples were collected from 11 stingrays by ventral tail venipuncture on three occasions and placed in blood tubes containing either lithium heparin (LH) (2 mL blood: 3 mL lithium heparin tube), elasmobranch modified anticoagulant citrate dextrose (E-ACD) (3 mL blood: 0.35 mL E-ACD), or elasmobranch modified heparin ethylenediamine tetraacetic acid (hepEDTA) (3 mL: 0.1 mL hepEDTA). Subjectively, LH samples had the greatest gross hemolysis and ACD samples the least. Cellular morphology on blood smears also appeared affected most by LH and least by hepEDTA. Significant differences (p<0.05) were greater means for PCO₂ and PO₂ on ACD, and HCO₃ on hepEDTA; and lower means for pH on ACD, and pH, total CO₂, and O₂ saturation on hepEDTA than LH samples. Whole blood in ACD cannot be used for base excess, HCO₃, total CO₂ concentrations, or O₂ saturation determinations by i-Stat. Significant differences (p<0.05) in plasma biochemistries were greater mean concentrations of phosphorus, glucose, sodium, and potassium on ACD; and AST enzyme, phosphorous, and potassium on hepEDTA samples; and lower mean concentrations for globulin, urea nitrogen, and calcium on ACD; and urea nitrogen and calcium on hepEDTA than on LH anticoagulant samples. These differences appear to reflect interactions between stingray blood and respective osmolality, pH, and chemical composition of these anticoagulants and should be considered when selecting an anticoagulant for marine elasmobranch blood samples with high plasma osmolality. The LH appeared to be the better anticoagulant for blood gas and acid-base, and biochemical analyte determinations. The hepEDTA anticoagulant appeared best for blood smears.