Co-oximetry in clinically healthy dogs and effects of time of post sampling on measurements.

OBJECTIVES

Co-oximetry is a complex and valuable laboratory method that measures haemoglobin species and oxygenation status by multi-wavelength spectrophotometry. The purpose of this study was to establish reference intervals for clinically healthy dogs and to determine the effect of time of analyses and sex of animals on the accuracy of results.

METHODS

Blood was collected from 27 healthy adult dogs of various breeds and sex. Co-oximetry was performed on a CCX co-oximeter that measures eight haemoglobin and oxygen transport related parameters: carboxyhaemoglobin (COHb), deoxyhaemoglobin (HHb), oxyhaemoglobin (O(2)Hb), methaemoglobin (MetHb), total haemoglobin (tHb), oxygen saturation (SO(2)%), oxygen content (O(2)Ct) and oxygen capacity (O(2)Cap).

RESULTS

Results obtained after 2 and 4 hours were not significantly different from those obtained immediately after sampling. But after 48 hours, the results for total haemoglobin, oxygen saturation, oxyhaemoglobin, oxygen content and oxygen capacity were significantly lower, and carboxyhaemoglobin and deoxyhaemoglobin values were significantly higher than determination immediately after sampling. Gender had no significant impact on co-oximetry values.

CLINICAL SIGNIFICANCE

Co-oximetry offers several advantages compared with other methods, including ease of use, increased accuracy and greater differentiation among haemoglobin species.