One of the most effective methods for mice is submandibular (facial) vein blood collection.
When performed correctly by trained personnel, this technique yields the maximum allowable sample volume while causing minimal trauma to the animal. Here is a step-by-step breakdown of the procedure, equipment, and safety considerations.
Why Choose the Submandibular Vein?
This method is ideal when you need a relatively large single volume of blood. If your study design requires serial sampling, best practice dictates alternating sides to let the initial puncture site completely heal.
Note: Because of the high volume it yields, this technique is not recommended for frequent, small-volume blood draws.
Necessary Supplies
Before bringing your animal into the hood, ensure you have the following prepped:
Isoflurane anesthesia system (with induction chamber and nosecone)
25–22 gauge needles OR a 4mm animal lancet
Sterile gauze sponges
Blood collection tubes (or pipettes)
Step-by-Step Procedure
1. Anesthesia and Preparation Unless your specific protocol includes approved justification for conscious collection, always begin by anesthetizing the mouse with isoflurane in an induction chamber.
2. Proper Restraint Remove the mouse from the chamber and use your non-dominant hand to scruff the loose skin over the shoulders and behind the ears. The key here is tension—the skin must be pulled taut over the mandible to visualize the area and prevent movement.
Pro-Tip for Beginners: If you are still building your speed, transfer the anesthetized mouse to a nosecone. This secures your ability to complete the draw without rushing before the animal recovers from the initial chamber anesthesia.
( Demonstration of a proper scruff restraint on a mouse, highlighting the taut skin stretched smoothly over the cheek and mandible.)
3. Locating the Puncture Site Accuracy is everything to avoid adverse neurological effects or hemorrhage. You are aiming slightly behind the mandible (caudal to the scent gland, but in front of the ear canal).
To find the exact vascular sweet spot, visualize two intersecting lines:
Line A: A straight line from the bottom of the mandible extending to the back (caudal) portion of the ear.
Line B: A straight line from the top of the eye extending to the point of the shoulder.
The Target: Puncture the vein exactly where these two lines intersect.
( A diagram of a mouse’s face with colored lines illustrating the intersection point between the eye-to-shoulder line and the mandible-to-ear line.)
4. The Puncture and Collection Using your needle or lancet, employ a swift, controlled lancing motion. Do not go deep. Only the very tip of the needle should enter the vessel (a shallow depth of roughly 1 to 2 mm).
Blood will begin to flow immediately. Quickly collect the sample using your pipette or collection tube.
(Insert Image: Action shot showing the tip of a lancet positioned at the correct intersection point on the cheek, with a collection tube ready just below.)
5. Hemostasis and Recovery The moment you have your required sample volume, immediately apply gentle, steady pressure to the puncture site using a gauze sponge. Maintain this pressure until bleeding has completely stopped.
Once hemostasis is confirmed and the animal has fully recovered from the anesthesia, safely return them to their home cage.
Potential Adverse Effects
Animal welfare is the top priority in any diagnostic or experimental setting. Incorrect usage, particularly puncturing too deeply or in the wrong location, can lead to severe complications. Always monitor the animal closely after the procedure for:
Prolonged hemorrhage
Neurologic deficits, most commonly presenting as a head tilt
By following these anatomical landmarks and practicing precise depth control, you can ensure high-quality sample collection with minimal distress to your subjects.
For video,
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