A prospective study of 90 dogs presenting for emergency surgery found venous and arterial lactate concentrations were associated with each other, with the strength of that association varying by whether the dog was hyperlactatemic.
What the study found
Venous lactate and glucose concentrations correlated well with arterial values in dogs presenting for emergency surgery. The correlation between arterial and venous lactate was very strong overall but weakened in dogs with normal lactate concentrations. Venous lactate detected arterial hyperlactatemia with 81.8% sensitivity and 88.6% specificity. No correlation was found between arterial lactate and glucose concentrations.
How the study was built
This was a prospective clinical study conducted at a university veterinary teaching hospital between June 2015 and March 2024. Ninety client-owned dogs presenting for emergency surgery were enrolled. Arterial blood samples were collected from the dorsal pedal artery and venous samples from the jugular vein, ≤5 minutes apart, and lactate and glucose concentrations were measured with portable devices. Dogs with known diabetes mellitus were excluded.
The number, and its error bars
In 90 client-owned dogs presenting for emergency surgery at a university veterinary teaching hospital, arterial and venous lactate concentrations showed a very strong correlation (ρ = 0.850; 95% confidence interval: 0.766-0.905; p < 0.001). Based on arterial blood, 35 of 90 dogs (38.9%) were hyperlactatemic; based on venous blood, 41 of 90 dogs (45.6%) were hyperlactatemic. Venous lactate detected arterial hyperlactatemia with 81.8% sensitivity and 88.6% specificity.
In dogs with arterial hyperlactatemia, the correlation between arterial and venous samples remained very strong (ρ = 0.835; 95% CI: 0.683-0.918; p < 0.001). In normolactatemic dogs, the correlation was fair (ρ = 0.488; 95% CI: 0.224-0.685; p < 0.001).
Glucose concentrations also correlated very strongly between arterial and venous samples (ρ = 0.970; 95% CI: 0.950-0.982; p < 0.001). No correlation was found between arterial lactate and glucose concentrations (ρ = −0.57; 95% CI: −0.261 to −0.152; p = 0.593).
What the authors say it cannot tell you
The abstract does not state limitations explicitly. The study population was dogs presenting for emergency surgery at a single teaching hospital, measured with portable devices, sampled from specific sites (dorsal pedal artery and jugular vein). The findings describe associations in this population but cannot establish causation. The results may not generalize to other patient populations, sampling sites, or measurement methods.
Who paid for it
The abstract does not report funding sources and does not disclose conflicts of interest.
What this means for your practice
VeterinaryPracticeNow's read, not the study's. Everything in this section is our editorial interpretation for practice owners. The study does not claim any of it.
The correlation held up well when lactate was elevated, the subset where we actually need the number to be right. It weakened when lactate was normal or near-normal, which is the zone where a venous sample might falsely reassure. That's the clinical trap: venous lactate is most reliable exactly when the patient is sickest, and least reliable when the patient looks borderline and we're trying to decide whether to escalate.
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The glucose finding matters because it kills the shortcut some of us were taught, that hyperglycemia in a sick dog means the lactate is probably elevated too. The study found no relationship. We have to measure both if we want both.
For practices where arterial access is technically difficult or where less experienced staff handle initial stabilization, this gives evidence for considering venous sampling for lactate. The trade-off the study shows: venous samples missed some hyperlactatemic cases, particularly in the borderline range. The gain is faster sampling, lower patient morbidity from fewer failed arterial sticks, and a workflow that doesn't require arterial access for every triage.