How do you give a rat an injection in the scruff? - briefly
Secure the animal by gently pinching the loose skin on the dorsal neck, keeping it restrained without excessive pressure. Insert a fine‑gauge needle at a shallow angle into the subcutaneous tissue and deliver the prescribed volume.
How do you give a rat an injection in the scruff? - in detail
Administering a subcutaneous or intraperitoneal injection to a laboratory rat by holding the skin on the back of the neck requires precise technique and strict adherence to aseptic standards.
First, gather all necessary supplies: sterile syringes (1 ml or 2.5 ml), appropriate gauge needles (25‑27 G for subcutaneous, 22‑25 G for intraperitoneal), the prepared drug solution, alcohol swabs, disposable gloves, and a sharps container. Verify drug concentration, calculate the exact dose based on the animal’s weight, and label the syringe clearly.
Second, prepare the animal. Place the rat on a clean, non‑slippery surface. Put on gloves and, if required by protocol, apply a brief isoflurane or CO₂ exposure to achieve mild sedation. Using the thumb and forefinger, grasp the loose skin at the nape of the neck (the “scruff”). Lift the skin gently upward, creating a small pocket. This maneuver immobilizes the animal without causing pain and exposes the subcutaneous space.
Third, execute the injection:
- Disinfect the injection site with an alcohol swab; allow it to dry.
- Hold the syringe like a pencil, needle bevel up.
- Insert the needle at a 45‑degree angle into the lifted skin pocket, penetrating only the subcutaneous layer for a subcutaneous dose or deeper (approximately 2‑3 mm) for an intraperitoneal dose.
- Aspirate gently to confirm absence of blood; if blood appears, withdraw and select a new site.
- Depress the plunger steadily to deliver the full volume.
- Withdraw the needle swiftly and apply gentle pressure with a sterile gauze to the site.
Finally, release the animal from restraint, observe for at least five minutes for adverse reactions, and place the rat back in its cage. Dispose of the needle and syringe in the designated sharps container, and record the procedure in the animal care log, noting dose, site, and any observations.
Consistent practice of this method minimizes stress, ensures accurate dosing, and maintains compliance with institutional animal welfare guidelines.