What considerations are important when performing blood collection procedures in mice?

• A. Only collecting blood from the heart with deep anesthesia.
• B. Collecting as much as possible without anesthesia.
• C. Using non-sterile technique to speed up.
• D. Anesthesia/analgesia as appropriate, asepsis, selecting the site (tail vein, saphenous), and minimizing volume.

Answer: (D)

Blood collection in mice should balance getting a usable sample with minimizing pain and distress. The best approach includes providing anesthesia or analgesia as appropriate, using aseptic technique, selecting a sampling site such as the tail vein or lateral saphenous vein, and limiting the volume drawn to what is necessary. Anesthesia or analgesia reduces pain during and after the procedure, aseptic technique prevents infection and sample contamination, and choosing sites like the tail vein or saphenous vein allows smaller, repeatable samples with less stress. Collecting without anesthesia or using non-sterile technique increases suffering and infection risk, and more invasive methods like heart puncture are reserved for terminal procedures. Keeping within minimal effective volumes and using proper technique protects both animal welfare and sample quality.