Abstract
OBJECTIVE
To assess the effect of hemodilution on PCV when commercial preheparinized venous blood gas (PH-VBG) syringes are used compared to directly filled Hct tubes, and to evaluate the impact of delayed centrifugation on PCV.
METHODS
A prospective study of 102 dogs presenting to a private emergency department between November 1, 2023, and February 29, 2024, with 306 corresponding blood samples. Samples were collected by direct venipuncture. Samples were analyzed with the use of 3 methods: directly filled microhematocrit tubes (direct), PH-VBG syringe (PH-VBG), and PH-VBG syringe with a 15-minute delay before centrifugation (delayed PH-VBG).
RESULTS
Mean PCV of the direct method was 43.9%, the PH-VBG method was 41.7% (range, 11.0% to 60.0%; SD, 9.8%), and the delayed PH-VBG method was 40.1% (range, 7.0% to 60.0%; SD, 11.2%). When the direct and PH-VBG methods were compared, the direct method was biased on average 2.2% higher than the PH-VBG method, with limits of agreement (LOAs) of –0.9 to 5.3. The direct method was biased on average 3.8% higher than the delayed PH-VBG method, with LOAs of –4.3 to 11.9. In anemic dogs (n = 14), the direct method was biased on average 6.1% higher than the delayed PH-VBG method, with LOAs of –0.05 to 12.2. In nonanemic dogs (n = 88), the direct method was biased on average 2.3% higher than the PH-VBG method, with LOAs of –0.9 to 5.4.
CONCLUSIONS
Use of preheparinized syringes and delayed sample processing led to hemodilution and lower PCV values.
CLINICAL RELEVANCE
Direct venipuncture and immediate sample processing are recommended to ensure accurate PCV results.
