Finally, patient fear, stress, excitement, and struggle can alter some values, such as white blood cells (ie, presence of a stress leukogram), cortisol, and blood glucose (especially in cats). Repeated sampling from the same site can also increase leukocytes and platelets in the area, which could confound results. If a technician notes that any of these events are occurring, they should note it on the patient chart and inform the veterinarian in charge of the case to help aid in the most accurate interpretation of results.

Finally, Roach discussed handling considerations for fractious and fearful patients. “We really need to get away from the culture of calling in 5 staff members to lay on a dog to get blood from it,” she said, “By causing undue stress to our patients, we are just making things worse for the next time.” Instead, she recommends using Feliway spray for cats, spending time with canine patients to improve trust, and using minimal restraint and distraction when possible. In cases where a blood draw is planned, pre-medicating patients with trazodone and/or gabapentin, depending on the species, can be very helpful. In some cases, chemical restraint in the form of injectable sedation will be necessary.

In some cases, other sampling sites must be considered when traditional venipuncture sites are not easily visible, scarred, swollen, or bruised. When a small sample size is needed, such as for a blood glucose or lactate reading or creation of a blood smear, the marginal ear vein can be used. Roach also notes the dorsal pedal vein can be helpful in obese patients or patient with peripheral edema, as the foot is usually less swollen and has less fat present.

The dorsal metatarsal artery is used most commonly to collect these samples. Patients should be positioned in lateral recumbency. The needle should be inserted at the site where the pulse is best palpated. Alternative sites include the femoral artery and, for anesthetized patients, the sublingual artery.

Phlebotomy is an important skill for veterinary nurses to master. Taking a few moments to plan an approach through site selection, patient positioning, and collecting the appropriate-sized equipment can maximize outcomes. Reducing patient stress should be a priority when obtaining samples from dogs and cats to minimize alteration to the sample and prevent the patient from becoming more reactive for future blood draws. When blood draws become difficult, technicians should not get discouraged, but instead consider alternative approaches and sites to obtain the needed samples.