Blood Sampling Techniques in Laboratory Animals

Blood sampling in laboratory animals encompasses a range of methods designed to balance data quality with animal welfare. Techniques include peripheral puncture of superficial veins (such as the saphenous and tail veins), facial or submandibular vein phlebotomy, retro-orbital sinus puncture and surgically implanted indwelling catheters (jugular, femoral or auricular). Each approach varies in invasiveness, sample volume, repeatability and the need for anaesthesia or restraint. Refinement efforts focus on minimising pain and distress, optimising sample integrity and reducing animal numbers through serial sampling within the same subject. Innovations such as port-based catheter systems permit repeated collections without repeated anaesthesia, and procedural acclimation has been shown to mitigate stress responses. Standardisation of handling, anticoagulant use and sample processing—including dilution correction for automated cell counts—further enhances reproducibility across studies. Global application spans pharmacokinetics, haematology, immunology and disease modelling, with adherence to the 3Rs (Replacement, Reduction, Refinement) underpinning ethical practice and technological development.

Research from Nature Portfolio

Recent studies have demonstrated the utility of simultaneous jugular vein and cisterna magna catheterisation via a subcutaneous port in rats, enabling daily blood and cerebrospinal fluid sampling over two weeks without repeated anaesthesia or loss of catheter patency. This system reduces the need for terminal bleeds and permits longitudinal biomarker analysis within individual animals. A foundational evaluation of point-of-care glucometers in mice compared readings from retro-orbital sinus and tail-tip blood against laboratory assays, revealing device-dependent biases and consistently higher glucose measurements under hyperglycaemic conditions. These findings underscore the importance of method-specific calibration and standardised sampling sites for reliable metabolic studies.

Research from all publishers

Studies in mice have shown that prior acclimation to handling and the sampling environment significantly lowers physiological stress markers—blood glucose and faecal corticosterone—across tail docking, caudal vein and saphenous vein puncture, with saphenous bleeding yielding the lowest stress when combined with acclimation. An optimised protocol for murine peripheral blood collection and dilution correction has been established, employing precise blood-to-anticoagulant ratios to minimise clotting, reduce sample volume requirements and improve accuracy of platelet and red blood cell counts, thereby decreasing inter-animal variability and animal numbers. Comparative work assessing retro-orbital plexus versus facial vein sampling in mice indicates that facial vein phlebotomy—when performed by both novice and experienced personnel—shortens collection time, lowers corticosterone responses, and causes less tissue damage, recommending it as a refinement for serial sampling.

Blood Sampling Techniques in Laboratory Animals publication trend

The graph below shows the total number of articles in blood sampling techniques in laboratory animals across all publications each year (not limited to Nature Index journals).

Technical terms

Indwelling venous catheter: A surgically implanted device that provides long-term vascular access for repeated sampling without repeated puncture or anaesthesia.

Retro-orbital sinus puncture: Blood collection from the venous plexus located behind the eye, often yielding moderate volumes but requiring careful technique.

Facial vein phlebotomy: Withdrawal of blood from the ventral facial (submandibular) vein in rodents, enabling rapid sampling with minimal restraint.

Saphenous vein puncture: Sampling via the lateral saphenous vein on the hind limb, suitable for small volumes without anaesthesia in acclimated animals.

3Rs: The ethical framework of Replacement, Reduction and Refinement guiding humane and scientifically robust animal research.

References

1. A technique for repeated blood and cerebrospinal fluid sampling from individual rats over time without the need for repeated anesthesia. Scientific Reports (2024).
2. Evaluation of the appropriateness of using glucometers for measuring the blood glucose levels in mice. Scientific Reports (2016).
3. Acclimation and Blood Sampling: Effects on Stress Markers in C57Bl/6J Mice. Animals (2023).
4. An Optimized Method of Collecting Murine Peripheral Blood and Dilution Correction for Accurate Blood Cell Enumeration. Current Protocols (2023).
5. Comparison of murine retroorbital plexus and facial vein blood collection to mitigate animal ethics issues. Laboratory Animal Research (2021).