Evaluation of toenail blood samples for blood gas analysis in the dog

Blood gas values were compared in blood collected from cut toenails and femoral arteries in 50 healthy crossbred dogs that were sedated and allowed to breathe room air spontaneously. Blood samples from cut toenails were collected by microcapillary technique with Natelson tubes. Femoral artery samples were collected by arterial puncture. Blood values for PO2, PCO2, pH, and HCO3 were compared. There was good correlation for pH, PCO2, and bicarbonate, but not for PO2. Microcapillary samples should be collected in 10 seconds or less for the most accurate results. A metal mixing "flea" was unnecessary. When properly handled, the Natelson tube technique provides an alternative method for collection of blood gas samples.