Effect of sample handling on venous PCO₂, pH, bicarbonate, and base excess measured with a point‐of‐care analyzer

Abstract

Objective: The purpose of this study was to determine the effect of timing of analysis, collection tube type and repeated opening of sample tubes on venous PCO2, pH, HCO3, and base excess (BE) results. Design: Prospective experimental study, paired sample analysis. Setting: Veterinary Medical Teaching Hospital. Animals: Twenty dogs. Interventions: Jugular venous blood samples. Measurements and main results: PCO2, pH, HCO3, and BE were determined immediately following collection (control) and at selected times up to 30 minutes after placement in either screw top or vacuum heparin collection tubes. A different set of screw top and vacuum heparin collection tubes were sampled repeatedly over time for up to 15 minutes. In the screw top delayed analysis group, only pH changed significantly at one time point. PCO2 decreased significantly in all other groups and resulted in a significant reciprocal pH change in the vacuum tubes with either delayed single analysis or repeated sampling. HCO3 and BE declined significantly in multi‐sampled vacuum tubes and HCO3 also decreased significantly in multi‐sampled screw top tubes. Conclusions: Analysis of acid–base status is optimally performed on freshly drawn blood. However, when it is anticipated there will be a delay in analysis of samples kept at room temperature, the use of 2.0 mL plastic screw top heparin anticoagulant tubes may result in fewer pre‐analytical errors than 3.5 mL glass vacuum tubes.

Development of a Multivariate Predictive Model to Estimate Ionized Calcium Concentration from Serum Biochemical Profile Results in Dogs

“…Our sample handling methodology required some limited air exposure, because the tubes must be opened at the time of sample analysis. However, no significant change in pCO 2 has been reported previously with the use of single sampled plastic lithium heparin screw‐top tubes . This finding was reflected in our study by the fact that the 10, 50, and 90% percentiles of sample pCO 2 were within the reference range, as were the 10, 50, and 90% percentiles of sample pH.…”

Blutgasanalyse beim Hund in der tierärztlichen Praxis – eine Übersicht

“…Nach der Probenentnahme werden alle Luftblasen aus der Spritze entfernt und die Spritze verschlossen (6). Die Messungen sollten unmittelbar stattfinden (36), andernfalls die Proben bis zur Analyse auf Eis bei 4 °C gelagert werden (maximal 30 Minuten) (9).…”

Determination of reference intervals and comparison of venous blood gas parameters using standard and non-standard collection methods in 24 cats

“…It has been stated that canine venous blood samples collected into LH tubes did not show significant changes in PvCO 2 , pH, HCO 3 or BE at eight different time points within 30 mins, with the exception of pH at 2 mins after sample collection compared with native blood analysed directly after collection. 6 The aim of this study was to determine in-house RIs for venous blood analysis with the RP500 blood gas analyser using BGSs and to determine whether immediate analysis of venous blood collected into LH tubes can replace anaerobic blood sampling into BGSs in cats.…”

“…It has been stated that canine venous blood samples collected into LH tubes did not show significant changes in PvCO 2 , pH, HCO 3 – or BE at eight different time points within 30 mins, with the exception of pH at 2 mins after sample collection compared with native blood analysed directly after collection. 6…”