Subcutaneous Injection Basics
What tissue layer is used for subcutaneous injections?
Subcutis (adipose tissue)
How long should the site be cleansed?
30 seconds
What type of medication is insulin classified as?
High‑alert medication
What must be done before withdrawing insulin?
Clean vial top and let air dry
A patient says, “I feel shaky,” and their hands are trembling. What should you offer the patient?
A quick source of glucose (juice, glucose tabs, etc.)
What is the maximum volume for an adult SC injection?
1 mL
Why must the site dry before injecting?
Prevents alcohol from entering tissue and causing discomfort
What is the standard insulin concentration?
U‑100 (100 units/mL)
Why inject air into the vial?
Maintains pressure for easier withdrawal
A patient reports feeling weak and dizzy before lunch. What should you do before administering insulin?
Check their blood glucose and ensure they are able to eat.
What needle gauge range is used for SC injections?
25–31 gauge
How long should you wait before removing the needle?
10 seconds
Which insulin must be gently rolled before use?
NPH (cloudy insulin)
Correct order for mixing Lispro and NPH insulins?
Air into NPH
Air into Lispro
Draw Lispro
Draw NPH
A patient asks why they must rotate injection sites. What is the correct teaching?
prevents tissue damage and ensures consistent insulin absorption.
When should a 45‑degree angle be used?
For thin patients or those with less adipose tissue
What should you do with the skinfold when using an insulin pen?
Keep pinched during injection, release before withdrawing
Which insulins can be mixed?
NPH + regular/aspart/lispro
intermediate - short or rapid acting
How many units do you prime an insulin pen with?
2 units
A patient on long‑acting insulin asks why they still need rapid‑acting insulin with meals. What should you explain?
Long‑acting insulin covers baseline needs; Rapid‑acting covers meal‑related glucose spikes.
Name two reasons to avoid an injection site.
Bruising, scarring, cellulitis, open skin, bony prominences
Why should you avoid massaging after a sub‑Q injection?
It can cause tissue irritation or bruising
Which insulins cannot be mixed?
Glargine and detemir
Long-acting insulin
How long should the pen remain in place after injection?
10 seconds
A patient reports polyuria, polydipsia, and fruity breath. Their blood sugar is 375 mg/dL. What should your next steps include?
Check ketones, encourage hydration, notify provider/instructor.