Mathieu, C. 2011. Comparative analysis of blood sampling techniques in the rat. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 738 (Abstract #PS81).

Blood sampling is one of the most common procedures performed on laboratory animals as part of scientific research. As an ongoing commitment, our institution has identified a need to improve the current blood sampling method in rats from both a sample quality and an animal welfare perspective. The aim of the study was to investigate and evaluate sampling from the jugular vein as a new blood sampling technique and compare it to the alternative methods available to establish the most appropriate method. A 22-d study was conducted comparing the lateral caudal vein, the jugular vein, the sublingual vein, and the orbital sinus as sites of blood sampling whereby animals were bled on several occasions. Throughout the study the following parameters were evaluated: clinical signs, body weight, localized damage at the site of sampling was examined visually, food and water consumption, indirect ophthalmoscopy, haematology, and clinical chemistry. All blood samples were visually assessed for haemolysis and clotting. On completion of the last blood sampling all animals were subjected to a macroscopic examination. The most pertinent findings noted included localized damage of the tail, increase in food consumption, body weight, and water consumption in animals sampled from the lateral caudal vein. Animals sampled from the orbital sinus had lens opacities findings. The jugular vein route was the only in-life sampling method that produced no clotted EDTA or trisodium citrate samples in week 4, whereas the other sampling methods were all associated with the presence of clotted samples in week 4. In particular, the orbital sinus route was associated with the largest number of clotted EDTA and trisodium citrate samples. When compared to alternative methods on welfare grounds, sampling from the jugular vein using our jugular bleeding technique does not require the animals to be heated or anaesthetized. One major benefit is that blood can be taken within 1 min of the animal being dosed as a result of the manual restraining, consequently reducing the stress which could potentially affect the physiologic state of the animal and variables attributed to the blood parameters.