How to administer a subcutaneous (sub Q) injection?

How to Administer a Subcutaneous Injection

The proper technique for subcutaneous (sub Q) injection involves using a 4-mm pen needle inserted at a 90-degree angle into appropriate subcutaneous tissue, after proper site selection and preparation, to ensure medication is delivered safely and effectively. 1

Preparation Steps

• Clean your hands and gather all necessary supplies including medication, syringe with appropriate needle (26-27 gauge, ½-inch or shorter recommended), alcohol swabs, and sharps container 1
• Check medication label to verify correct medication, dose, and expiration date 1
• For cloudy insulin preparations (except rapid/short-acting insulin), gently roll the vial between palms or shake gently to resuspend the insulin 1
• When using a vial, inject an amount of air equal to the dose you'll withdraw to avoid creating a vacuum 1
• When mixing insulins, draw the clear rapid/short-acting insulin first, followed by the cloudy intermediate/long-acting insulin 1
• Inspect the syringe for air bubbles and remove them by gently tapping the upright syringe 1

Injection Site Selection

• Recommended sites for subcutaneous injection include: 1

  • Abdomen (2 fingerbreadths away from the umbilicus)
  • Upper third anterior lateral aspect of the thighs
  • Posterior lateral aspect of the upper buttocks and flanks
  • Middle third posterior aspect of the upper arm

• Site selection considerations: 1, 2

  • Abdomen has the fastest absorption rate
  • Arms have intermediate absorption
  • Thighs and buttocks have slower absorption
  • Avoid areas with lipohypertrophy, inflammation, or scarring

• Rotate injection sites systematically within one area (e.g., within the abdomen) rather than rotating to different areas with each injection to maintain consistent absorption 1

Injection Technique

1. Clean the injection site with an alcohol swab and allow to dry 1

2. Properly grasp the skin: 1

   • For most adults using a 4-mm needle: inject at 90° angle without pinching skin
   • For thin individuals or when using longer needles: pinch a fold of skin between thumb and index finger to lift subcutaneous tissue away from muscle

3. Insert the needle: 1

   • Insert at 90° angle for most adults with appropriate needle length
   • Insert at 45° angle for thin individuals or children when using longer needles
   • Ensure needle is perpendicular to the skin surface when using the 90° technique

4. Administer the medication: 1, 3

   • Optional: aspirate by pulling back slightly on the plunger to check for blood return (though some guidelines consider this unnecessary) 1
   • If blood appears in the syringe, withdraw the needle, discard properly, and prepare a new injection
   • Depress the plunger at a steady rate that doesn't cause excessive pain
   • Keep the needle in place for at least 6-10 seconds after injection to ensure complete medication delivery 1, 3

5. Remove the needle and dispose properly: 1, 3

   • Apply gentle pressure to the injection site for about 1 minute
   • Do not rub the area
   • Dispose of used needles in a puncture-resistant sharps container
   • Never recap needles to avoid needlestick injuries

Special Considerations

• For insulin injections: 1

  • Use 4-mm pen needles for all patients regardless of age, BMI, or body type when possible
  • For cloudy insulins, ensure proper resuspension by rolling and tipping the vial/pen 10 times
  • Store unopened insulin in refrigerator; in-use insulin can be kept at room temperature (below 86°F/30°C) for specified periods

• For children and thin adults: 1

  • Use shorter needles (4-mm) when possible
  • A 2-finger lifted skinfold technique is recommended to prevent intramuscular injection
  • The lifted skinfold is more effective in the abdomen than in the thigh

• Common pitfalls to avoid: 1

  • Intramuscular injection (causes faster absorption and potential hypoglycemia with insulin)
  • Intradermal injection (too shallow, causes pain and poor absorption)
  • Injecting into lipohypertrophy (causes variable absorption)
  • Failure to rotate injection sites (leads to tissue damage)
  • Improper needle disposal (safety risk)

By following these guidelines, subcutaneous injections can be administered safely and effectively, ensuring proper medication delivery while minimizing complications and patient discomfort.