💉 Introduction
Insulin administration is one of the most important pharmacological skills tested on the NCLEX. Nurses must understand the types of insulin, correct timing, injection sites, storage, and safe mixing techniques to prevent medication errors and patient complications such as hypoglycemia.
This free NCLEX insulin practice test includes 100 high-yield multiple-choice questions with detailed rationales designed to strengthen your understanding of dosage calculation, insulin combinations, patient teaching, and safety protocols.
Whether you are preparing for the NCLEX-RN or NCLEX-PN, this quiz will help you identify your weak areas and gain confidence in diabetes management — one of the most tested topics in nursing pharmacology.
🩸 Insulin Administration NCLEX Practice Questions
1. A nurse is preparing to administer NPH insulin. Which statement about NPH insulin is correct?
A. It is a rapid-acting insulin.
B. It should be given immediately before meals.
C. It has a cloudy appearance and can be mixed with regular insulin.
D. It should not be mixed with any other insulin.
Answer: C
Rationale: NPH insulin (intermediate-acting) is cloudy due to added protamine and can be safely mixed with regular insulin. It provides a slower onset and longer duration, making it suitable for baseline insulin control.
2. Which insulin has the fastest onset of action?
A. NPH insulin
B. Regular insulin
C. Lispro (Humalog)
D. Glargine (Lantus)
Answer: C
Rationale: Lispro (Humalog) is a rapid-acting insulin with an onset of 10–15 minutes. It is given immediately before meals to control postprandial glucose spikes.
3. When mixing regular and NPH insulin, the nurse should:
A. Draw up NPH first, then regular insulin.
B. Draw up regular insulin first, then NPH insulin.
C. Shake both vials before drawing.
D. Mix insulin glargine with NPH.
Answer: B
Rationale: Always draw up clear (regular) before cloudy (NPH) to prevent contamination of the regular insulin vial. Glargine should never be mixed with other insulins.
4. Which site is most appropriate for insulin administration?
A. Deltoid
B. Abdomen
C. Forearm
D. Buttocks
Answer: B
Rationale: The abdomen provides the most consistent absorption rate for insulin injections, especially for rapid-acting types.
5. A patient receives Lispro insulin at 8:00 a.m. The nurse should ensure the patient eats breakfast by:
A. 8:30 a.m.
B. 9:00 a.m.
C. 7:45 a.m.
D. 10:00 a.m.
Answer: A
Rationale: Lispro has a rapid onset (10–15 minutes); food must be available within 15 minutes to prevent hypoglycemia.
6. What is the peak time of Regular insulin (Humulin R)?
A. 30 minutes
B. 2–4 hours
C. 6–8 hours
D. 12 hours
Answer: B
Rationale: Regular insulin peaks 2–4 hours after injection; this is when hypoglycemia is most likely to occur.
7. Which insulin cannot be mixed with other insulins?
A. NPH
B. Regular
C. Lispro
D. Glargine
Answer: D
Rationale: Insulin glargine (Lantus) and detemir (Levemir) are long-acting insulins and must never be mixed due to pH differences.
8. A nurse should teach a patient to inject insulin at which angle when using a short needle?
A. 30 degrees
B. 45 degrees
C. 90 degrees
D. 15 degrees
Answer: C
Rationale: A 90-degree angle ensures proper subcutaneous delivery, especially for patients with adequate subcutaneous tissue.
9. What should a nurse do if a patient accidentally injects too much insulin?
A. Give glucagon if available.
B. Wait for symptoms.
C. Encourage water intake.
D. Administer more insulin.
Answer: A
Rationale: Excess insulin causes hypoglycemia. Administering glucagon IM or IV glucose helps rapidly raise blood sugar levels.
10. The nurse should store unopened insulin vials:
A. At room temperature
B. In the freezer
C. In the refrigerator
D. In direct sunlight
Answer: C
Rationale: Unopened insulin should be refrigerated to maintain stability; opened vials may be kept at room temperature for up to 28 days.
11. Which insulin has no pronounced peak and provides a steady effect for 24 hours?
A. NPH
B. Regular
C. Glargine (Lantus)
D. Lispro
Answer: C
Rationale: Glargine is long-acting with no peak, offering a consistent 24-hour basal coverage.
12. What should the nurse do before administering insulin?
A. Massage the injection site
B. Assess the patient’s blood glucose level
C. Give the insulin even if the patient is NPO
D. Warm the insulin vial
Answer: B
Rationale: Always check blood glucose to determine the need for insulin and prevent hypoglycemia.
13. Mixing Regular and NPH insulin results in:
A. Faster absorption
B. Basal and mealtime coverage
C. Decreased insulin potency
D. Reduced hypoglycemia risk
Answer: B
Rationale: The combination provides immediate (Regular) and intermediate (NPH) control — ideal for maintaining stable glucose levels.
14. What is the correct order for preparing mixed insulin doses?
A. Cloudy → Clear
B. Clear → Cloudy
C. Shake both vials first
D. Doesn’t matter
Answer: B
Rationale: Always draw “clear to cloudy” (Regular before NPH) to prevent contamination of the short-acting insulin.
15. Which insulin requires the nurse to monitor for hypoglycemia one hour after administration?
A. NPH
B. Regular
C. Lispro
D. Glargine
Answer: C
Rationale: Lispro peaks in about 30–90 minutes; monitor for early signs of hypoglycemia during this period.
16. A nurse educates a diabetic patient to rotate insulin injection sites to:
A. Improve absorption consistency
B. Increase potency
C. Reduce pain only
D. Decrease insulin resistance
Answer: A
Rationale: Site rotation prevents lipohypertrophy and ensures even absorption of insulin.
17. What symptom indicates insulin overdose?
A. Dry skin
B. Tremors and confusion
C. Polyuria
D. Flushed face
Answer: B
Rationale: Tremors, confusion, sweating, and irritability are signs of hypoglycemia due to excessive insulin.
18. What should the nurse do if blood glucose is 60 mg/dL before a scheduled insulin dose?
A. Administer insulin as prescribed.
B. Hold insulin and give a snack.
C. Administer an additional dose.
D. Give IV insulin.
Answer: B
Rationale: A blood glucose of 60 mg/dL is low; hold insulin and provide carbohydrates to prevent hypoglycemia.
19. What type of insulin is used for sliding scale therapy?
A. NPH
B. Regular
C. Glargine
D. Detemir
Answer: B
Rationale: Regular insulin or rapid-acting insulins are commonly used in sliding scale regimens for tight glucose control.
20. Which instruction is correct for a patient using an insulin pen?
A. Shake the pen before every use.
B. Prime with 1–2 units before each dose.
C. Store pen needles in the refrigerator.
D. Use the same needle multiple times.
Answer: B
Rationale: Priming ensures accurate dosage delivery by clearing air bubbles from the pen tip.
21. What is the expected onset time for Glargine insulin?
A. 15 minutes
B. 1 hour
C. 4 hours
D. Immediate
Answer: B
Rationale: Glargine begins working within 1–1.5 hours and provides steady basal control without peaks.
22. When should a patient take insulin glargine (Lantus)?
A. Before each meal
B. At bedtime or same time daily
C. Only when glucose is elevated
D. Every 4 hours
Answer: B
Rationale: Glargine is long-acting; consistent daily timing (often bedtime) maintains steady blood sugar levels.
23. A nurse identifies lipohypertrophy at the patient’s insulin injection site. The correct action is:
A. Continue injections at that site.
B. Stop insulin therapy.
C. Rotate injection sites.
D. Massage the site vigorously.
Answer: C
Rationale: Repeated injections in the same site cause fatty deposits (lipohypertrophy); rotating sites prevents this.
24. Which insulin is safe for IV administration?
A. NPH
B. Regular insulin
C. Lispro
D. Detemir
Answer: B
Rationale: Regular insulin is the only form suitable for IV use, commonly used in emergencies like DKA.
25. A nurse explains to a patient that unopened insulin vials should be:
A. Frozen for long-term storage
B. Kept at room temperature indefinitely
C. Refrigerated until opened
D. Stored under sunlight for warmth
Answer: C
Rationale: Insulin remains stable when refrigerated; once opened, vials can be stored at room temperature for up to 28 days.
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Question 26
A patient with type 1 diabetes reports taking insulin but continues to experience elevated blood glucose levels. Which factor is most likely contributing to insulin ineffectiveness?
A. Rotating injection sites regularly
B. Injecting insulin into lipohypertrophic areas
C. Administering insulin 30 minutes before meals
D. Using a new syringe each time
Answer: B. Injecting insulin into lipohypertrophic areas
Rationale: Repeated injections into the same site cause lipohypertrophy (fatty lumps), which slows insulin absorption, reducing effectiveness. Rotating sites helps prevent this.
Question 27
The nurse teaches a client to store unopened insulin vials. Which instruction is correct?
A. Keep them at room temperature indefinitely
B. Store in the freezer until use
C. Keep refrigerated until the expiration date
D. Store in direct sunlight for better preservation
Answer: C. Keep refrigerated until the expiration date
Rationale: Unopened insulin vials should be stored in a refrigerator. Once opened, most insulins can be kept at room temperature for 28 days.
Question 28
Which insulin has the fastest onset of action?
A. Regular insulin
B. Lispro (Humalog)
C. NPH insulin
D. Glargine (Lantus)
Answer: B. Lispro (Humalog)
Rationale: Lispro is a rapid-acting insulin that begins working within 10–15 minutes, ideal for controlling post-meal glucose spikes.
Question 29
A patient accidentally injects rapid-acting insulin without eating. The nurse should first:
A. Administer glucagon
B. Give a snack containing carbohydrates
C. Recheck blood glucose in 2 hours
D. Encourage the patient to rest
Answer: B. Give a snack containing carbohydrates
Rationale: To prevent hypoglycemia, the nurse should provide a quick source of carbohydrates when insulin is taken without food.
Question 30
Which statement indicates that a patient understands how to mix insulin?
A. “I will draw up the cloudy insulin first.”
B. “I will inject air into both vials before withdrawing insulin.”
C. “I will mix Lantus with Regular insulin.”
D. “I can mix all types of insulin together.”
Answer: B. “I will inject air into both vials before withdrawing insulin.”
Rationale: Injecting air into both prevents vacuum formation. Always draw up clear (Regular) insulin before cloudy (NPH) to avoid contamination.
Question 31
A nurse is preparing to administer 10 units of Regular insulin and 20 units of NPH. What is the correct order?
A. NPH first, then Regular
B. Regular first, then NPH
C. Mix both simultaneously
D. NPH only
Answer: B. Regular first, then NPH
Rationale: Clear before cloudy—Regular insulin should always be drawn first to avoid contaminating the vial.
Question 32
The nurse should instruct a client using an insulin pen to:
A. Store it horizontally
B. Share it with family members
C. Prime it before each use
D. Remove the needle after each use
Answer: C. Prime it before each use
Rationale: Priming ensures that air bubbles are expelled and the device delivers an accurate dose.
Question 33
A nurse gives insulin detemir at 8 p.m. When should the nurse expect it to peak?
A. 1 hour
B. 6 hours
C. 12 hours
D. Minimal peak
Answer: D. Minimal peak
Rationale: Detemir is a long-acting insulin with a minimal peak, providing steady basal glucose control.
Question 34
Which finding indicates hypoglycemia after insulin administration?
A. Flushed skin
B. Tremors and sweating
C. Dry mouth and thirst
D. Deep respirations
Answer: B. Tremors and sweating
Rationale: Hypoglycemia symptoms include shakiness, sweating, anxiety, and confusion due to low blood glucose.
Question 35
A diabetic patient who exercises daily should be taught to:
A. Skip insulin on exercise days
B. Exercise immediately after taking insulin
C. Eat a snack before exercise
D. Double insulin dose on those days
Answer: C. Eat a snack before exercise
Rationale: Exercise lowers blood glucose; a pre-exercise snack helps prevent hypoglycemia.
Question 36
What is the correct nursing action if insulin is mistakenly given to a non-diabetic patient?
A. Monitor glucose levels closely and give glucose as needed
B. Wait for symptoms to appear
C. Encourage rest and hydration
D. Do nothing unless symptoms develop
Answer: A. Monitor glucose levels closely and give glucose as needed
Rationale: Immediate monitoring and carbohydrate intake prevent severe hypoglycemia.
Question 37
Which insulin type cannot be mixed with any other insulin?
A. Regular
B. Lispro
C. Glargine
D. NPH
Answer: C. Glargine
Rationale: Glargine is long-acting and should never be mixed; it has a specific pH and formulation.
Question 38
Which instruction should be included when teaching a patient to use an insulin pump?
A. Change the insertion site every 2–3 days
B. Inject Regular insulin only
C. Disconnect during meals
D. Keep the pump in a refrigerator
Answer: A. Change the insertion site every 2–3 days
Rationale: Rotating sites prevents infection and ensures consistent absorption.
Question 39
Which lab result indicates insulin overdose?
A. Blood glucose 80 mg/dL
B. Blood glucose 55 mg/dL
C. Blood glucose 140 mg/dL
D. Blood glucose 200 mg/dL
Answer: B. Blood glucose 55 mg/dL
Rationale: A glucose level below 70 mg/dL signifies hypoglycemia due to excess insulin.
Question 40
For a diabetic patient who is NPO for surgery, the nurse should:
A. Hold all insulin
B. Administer half the usual basal dose
C. Give the full dose of insulin
D. Administer extra regular insulin
Answer: B. Administer half the usual basal dose
Rationale: Basal insulin maintains background glucose control even when the patient is not eating.
Question 41
Which factor increases insulin absorption rate?
A. Cold temperature
B. Massage after injection
C. Injecting in a scarred area
D. Injecting deeply into muscle
Answer: B. Massage after injection
Rationale: Gentle massage or heat increases blood flow, enhancing absorption.
Question 42
A patient is prescribed insulin lispro before meals. When should the nurse administer it?
A. 45 minutes before meals
B. Immediately before meals
C. 2 hours after meals
D. Only at bedtime
Answer: B. Immediately before meals
Rationale: Lispro acts rapidly; it should be given just before eating to prevent hypoglycemia.
Question 43
A diabetic patient shows confusion and slurred speech. What should the nurse do first?
A. Call the physician
B. Administer insulin
C. Check blood glucose
D. Give intravenous fluids
Answer: C. Check blood glucose
Rationale: Hypoglycemia can mimic stroke symptoms; confirm glucose levels before intervening.
Question 44
A nurse teaching self-injection of insulin should instruct the patient to inject at what angle?
A. 90° for normal weight
B. 45° for obese patients
C. 30° for all patients
D. 60° for thin patients
Answer: A. 90° for normal weight
Rationale: A 90° angle ensures proper subcutaneous delivery for most adults.
Question 45
When teaching about insulin storage during travel, the nurse should advise:
A. Keep insulin in checked luggage
B. Store insulin in carry-on bags
C. Place insulin in direct sunlight
D. Freeze insulin to preserve it
Answer: B. Store insulin in carry-on bags
Rationale: Extreme temperatures in checked luggage can damage insulin.
Question 46
Which time is best to check for nocturnal hypoglycemia?
A. 6 a.m.
B. 2 a.m.
C. 10 p.m.
D. Midnight
Answer: B. 2 a.m.
Rationale: Checking at 2–3 a.m. helps detect insulin-induced hypoglycemia during the night.
Question 47
A nurse should hold insulin if:
A. The patient is febrile
B. Blood glucose is 55 mg/dL
C. The patient just ate
D. Blood glucose is 120 mg/dL
Answer: B. Blood glucose is 55 mg/dL
Rationale: Hypoglycemia is a contraindication for further insulin administration.
Question 48
Which finding shows effective insulin therapy?
A. Fasting glucose 180 mg/dL
B. HbA1c 6.8%
C. Random glucose 250 mg/dL
D. HbA1c 9%
Answer: B. HbA1c 6.8%
Rationale: A1c below 7% indicates well-controlled diabetes.
Question 49
When teaching a patient using insulin pens, which point is essential?
A. Shake insulin pens before use
B. Never reuse pen needles
C. Store pens in freezer
D. Prime pen weekly
Answer: B. Never reuse pen needles
Rationale: Reusing needles increases the risk of infection and dulls the needle tip.
Question 50
Which insulin should the nurse administer at bedtime to maintain fasting glucose control?
A. Regular
B. NPH
C. Lispro
D. Glargine
Answer: D. Glargine
Rationale: Long-acting Glargine maintains basal control throughout the night without peaks.
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Question 51
A patient taking both NPH and Regular insulin asks, “Why do I need two types?” What is the best response by the nurse?
A. “Both have the same action but different brands.”
B. “NPH controls glucose later, while Regular controls glucose after meals.”
C. “You need both because one replaces the other.”
D. “They must be taken together for safety.”
Answer: B. NPH controls glucose later, while Regular controls glucose after meals.
Rationale: Regular insulin is short-acting for post-meal control, while NPH provides intermediate, long-term coverage.
Question 52
Which condition requires increased insulin dosage?
A. Hypothyroidism
B. Fever and infection
C. Fasting or skipped meals
D. Weight loss
Answer: B. Fever and infection
Rationale: Illness and stress increase blood glucose, requiring higher insulin doses.
Question 53
A nurse notes a patient’s insulin vial has clumps. The correct action is to:
A. Shake the vial vigorously
B. Roll the vial between palms
C. Discard the vial and get a new one
D. Warm it in hot water
Answer: C. Discard the vial and get a new one
Rationale: Clumping indicates that insulin has expired or been stored incorrectly.
Question 54
What is the onset of NPH insulin?
A. 15 minutes
B. 1–2 hours
C. 4 hours
D. Immediate
Answer: B. 1–2 hours
Rationale: NPH is an intermediate-acting insulin with an onset of 1–2 hours and a duration up to 18 hours.
Question 55
The nurse is teaching about rotating injection sites. Which statement indicates correct understanding?
A. “I’ll inject into the same spot for faster results.”
B. “I’ll rotate within one anatomical area before changing to another.”
C. “I can use my thighs only.”
D. “Rotation doesn’t matter.”
Answer: B. “I’ll rotate within one anatomical area before changing to another.”
Rationale: Rotating within the same area maintains consistent absorption rates.
Question 56
A client with diabetes develops swelling and redness at the injection site. The nurse should:
A. Continue using the same site
B. Report possible infection and rotate the site
C. Inject insulin deeper
D. Apply ice and re-inject immediately
Answer: B. Report possible infection and rotate the site
Rationale: Inflammation may indicate local infection or irritation; rotating sites prevents worsening.
Question 57
Which insulin is typically administered before bedtime?
A. Lispro
B. NPH
C. Regular
D. Detemir
Answer: D. Detemir
Rationale: Detemir is a long-acting insulin commonly given at bedtime to maintain overnight control.
Question 58
A patient’s blood glucose is 310 mg/dL before the scheduled insulin dose. What is the priority action?
A. Give insulin and recheck later
B. Hold insulin and notify provider
C. Assess for infection and check urine ketones
D. Give extra insulin
Answer: C. Assess for infection and check urine ketones
Rationale: Hyperglycemia with high readings could indicate ketoacidosis; assess before treatment.
Question 59
A nurse prepares to administer insulin using an insulin syringe marked in:
A. Milliliters (mL)
B. Units (U)
C. Milligrams (mg)
D. Grams (g)
Answer: B. Units (U)
Rationale: Insulin is always measured in units to ensure dosing accuracy.
Question 60
A patient using an insulin pump asks how often to change the reservoir. The correct reply is:
A. Every 24 hours
B. Every 2–3 days
C. Once a week
D. Only when empty
Answer: B. Every 2–3 days
Rationale: Insulin reservoirs and infusion sets are changed every 2–3 days to prevent infection and maintain potency.
Question 61
If a patient experiences Somogyi effect, the nurse should:
A. Increase evening insulin
B. Check 3 a.m. blood sugar
C. Skip bedtime snack
D. Stop all insulin doses
Answer: B. Check 3 a.m. blood sugar
Rationale: The Somogyi effect occurs when nighttime hypoglycemia leads to rebound morning hyperglycemia.
Question 62
A diabetic patient’s fasting glucose is 280 mg/dL after missing insulin for two days. The priority intervention is to:
A. Administer sliding-scale insulin
B. Recheck glucose in 4 hours
C. Give only fluids
D. Withhold insulin until lunch
Answer: A. Administer sliding-scale insulin
Rationale: Sliding-scale insulin corrects temporary hyperglycemia effectively.
Question 63
When teaching a patient about insulin storage, the nurse should include:
A. Keep insulin pens in the freezer
B. Store insulin vials in direct sunlight
C. Unopened insulin should be refrigerated
D. Opened vials must always be refrigerated
Answer: C. Unopened insulin should be refrigerated
Rationale: Unopened insulin remains potent in the refrigerator; opened vials can stay at room temperature for 28 days.
Question 64
Which insulin is cloudy in appearance?
A. Lispro
B. Glargine
C. NPH
D. Regular
Answer: C. NPH
Rationale: NPH is the only commonly used insulin that appears cloudy due to its protamine content.
Question 65
A nurse notes a patient’s morning blood sugar is consistently high despite bedtime insulin. What should the nurse suspect?
A. Dawn phenomenon
B. Hypoglycemia
C. Infection
D. Missed meals
Answer: A. Dawn phenomenon
Rationale: The dawn phenomenon causes early morning hyperglycemia due to increased cortisol and growth hormone.
Question 66
Which is an appropriate action when administering insulin to a thin elderly patient?
A. Use a long 1-inch needle
B. Pinch the skin to lift subcutaneous tissue
C. Inject into muscle tissue
D. Use the same site daily
Answer: B. Pinch the skin to lift subcutaneous tissue
Rationale: Elderly or thin patients have less fat; pinching prevents accidental intramuscular injection.
Question 67
A nurse is teaching a patient about insulin lispro. Which instruction is most important?
A. Take after eating
B. Inject immediately before eating
C. Take at bedtime
D. Mix with long-acting insulin
Answer: B. Inject immediately before eating
Rationale: Lispro is rapid-acting; administering it just before meals prevents hypoglycemia.
Question 68
Which patient statement indicates the need for further teaching?
A. “I can reuse my insulin syringe several times.”
B. “I’ll check my glucose before taking insulin.”
C. “I’ll rotate my injection sites.”
D. “I’ll store insulin at room temperature after opening.”
Answer: A. “I can reuse my insulin syringe several times.”
Rationale: Reusing syringes increases infection risk and dulls the needle.
Question 69
A nurse observes a patient injecting insulin into the deltoid muscle. What should the nurse do?
A. Praise the technique
B. Stop the patient and teach proper subcutaneous injection
C. Allow it if dose is small
D. Rotate to abdomen next time
Answer: B. Stop the patient and teach proper subcutaneous injection
Rationale: Insulin should be injected subcutaneously, not intramuscularly.
Question 70
A patient is prescribed insulin glargine (Lantus). The nurse knows this insulin:
A. Is short-acting
B. Has no peak effect
C. Is given only after meals
D. Is used for correction doses only
Answer: B. Has no peak effect
Rationale: Glargine provides steady, 24-hour basal control with no pronounced peak, reducing hypoglycemia risk.
Question 71
The nurse is preparing to mix Regular and NPH insulin. Which step is correct?
A. Roll Regular insulin
B. Draw NPH insulin first
C. Draw Regular insulin first
D. Shake NPH vigorously
Answer: C. Draw Regular insulin first
Rationale: Drawing clear insulin before cloudy prevents contamination of Regular insulin.
Question 72
Which meal timing is ideal for a patient taking Regular insulin?
A. Immediately before the meal
B. 30 minutes before the meal
C. After the meal
D. Any time during the day
Answer: B. 30 minutes before the meal
Rationale: Regular insulin has an onset of 30 minutes; it should be given before meals.
Question 73
A patient asks about symptoms of hypoglycemia. The nurse should teach the patient to look for:
A. Dry mouth and thirst
B. Sweating, tremors, and confusion
C. Flushed skin and rapid pulse
D. Increased appetite
Answer: B. Sweating, tremors, and confusion
Rationale: These are early signs of hypoglycemia that need immediate correction.
Question 74
A nurse is reinforcing dietary teaching for a diabetic patient. Which snack is best to prevent insulin-induced hypoglycemia?
A. A small apple and peanut butter
B. A sugar-free beverage
C. A cup of black coffee
D. Plain crackers
Answer: A. A small apple and peanut butter
Rationale: The combination of carbohydrates and protein stabilizes blood sugar longer.
Question 75
A diabetic patient using an insulin pump develops redness at the insertion site. What should the nurse do first?
A. Remove the cannula and rotate site
B. Apply ice and continue infusion
C. Tighten the adhesive
D. Increase the insulin dose
Answer: A. Remove the cannula and rotate site
Rationale: Redness or irritation indicates infection or tissue reaction; change the site to prevent worsening.
Question 76
A nurse is preparing to give insulin aspart to a patient. When should the nurse ensure the patient begins eating?
A. 15 minutes after injection
B. Immediately after injection
C. 30 minutes before injection
D. One hour after injection
Answer: B. Immediately after injection
Rationale: Aspart is a rapid-acting insulin; food should be ready to prevent hypoglycemia.
Question 77
What is the primary site for insulin absorption with the fastest rate?
A. Thigh
B. Buttocks
C. Abdomen
D. Upper arm
Answer: C. Abdomen
Rationale: The abdomen provides the most consistent and rapid absorption for insulin.
Question 78
The nurse instructs the patient to rotate insulin injection sites. Why is this important?
A. To reduce insulin effectiveness
B. To avoid lipodystrophy
C. To prevent bruising
D. To increase absorption rate
Answer: B. To avoid lipodystrophy
Rationale: Repeated injections in the same area can cause tissue hardening and uneven absorption.
Question 79
A nurse mixes Regular and NPH insulin in one syringe. Which statement is correct?
A. NPH should be drawn first
B. Regular insulin should be drawn first
C. Either can be drawn first
D. Insulins cannot be mixed
Answer: B. Regular insulin should be drawn first
Rationale: Clear before cloudy — drawing Regular first avoids contamination.
Question 80
A diabetic patient reports frequent hypoglycemia at night. Which adjustment might the provider make?
A. Increase morning insulin
B. Add bedtime snack
C. Eliminate long-acting insulin
D. Skip dinner
Answer: B. Add bedtime snack
Rationale: A small snack prevents overnight hypoglycemia by maintaining glucose levels.
Question 81
The nurse should teach that insulin glargine (Lantus) should not be:
A. Given once daily
B. Mixed with other insulins
C. Given subcutaneously
D. Administered at bedtime
Answer: B. Mixed with other insulins
Rationale: Glargine must never be mixed because it alters its long-acting properties.
Question 82
A patient on insulin develops tremors and sweating. The priority nursing action is to:
A. Check the blood sugar
B. Notify the physician
C. Give more insulin
D. Wait and observe
Answer: A. Check the blood sugar
Rationale: Hypoglycemia must be confirmed and treated immediately.
Question 83
Which insulin has the quickest onset of action?
A. Lispro
B. Regular
C. NPH
D. Glargine
Answer: A. Lispro
Rationale: Lispro acts within 10–15 minutes, ideal for meal-time glucose control.
Question 84
A nurse administers 12 units of Regular insulin at 7:00 AM. The nurse should monitor for hypoglycemia at approximately:
A. 7:15 AM
B. 8:00–10:00 AM
C. 12:00 PM
D. 3:00 PM
Answer: B. 8:00–10:00 AM
Rationale: Regular insulin peaks 2–4 hours after injection.
Question 85
A patient says, “I always inject insulin into the same spot so it works faster.” The nurse’s best response is:
A. “That’s fine if you’re consistent.”
B. “Rotating sites helps maintain even absorption.”
C. “Keep using the same area to avoid bruising.”
D. “Try injecting deeper next time.”
Answer: B. “Rotating sites helps maintain even absorption.”
Rationale: Site rotation prevents lipohypertrophy and maintains predictable absorption.
Question 86
Which insulin combination can be safely mixed in one syringe?
A. Glargine and Lispro
B. Regular and NPH
C. Detemir and NPH
D. Glargine and Regular
Answer: B. Regular and NPH
Rationale: These two insulins are compatible when mixed properly (clear before cloudy).
Question 87
A nurse is teaching a patient how to prepare insulin injections. Which step should be performed first?
A. Inject air into the NPH vial
B. Inject air into the Regular vial
C. Withdraw insulin
D. Mix insulins
Answer: A. Inject air into the NPH vial
Rationale: Injecting air into the cloudy vial first prevents contamination.
Question 88
The nurse prepares to administer insulin to a patient who is NPO for surgery. What is the best action?
A. Give full dose
B. Hold insulin and notify provider
C. Give double dose later
D. Skip insulin entirely
Answer: B. Hold insulin and notify provider
Rationale: NPO patients need adjusted doses to avoid hypoglycemia.
Question 89
A patient on insulin reports vision changes. What should the nurse consider?
A. It’s a normal sign of aging
B. It may indicate fluctuating glucose levels
C. Insulin causes permanent eye damage
D. It’s unrelated to diabetes
Answer: B. It may indicate fluctuating glucose levels
Rationale: Vision changes often occur due to unstable blood glucose levels.
Question 90
A nurse teaches that unopened insulin should be stored:
A. In the freezer
B. At room temperature
C. In the refrigerator
D. In sunlight
Answer: C. In the refrigerator
Rationale: Refrigeration maintains insulin stability until opened.
Question 91
When injecting insulin, the needle should enter the skin at what angle?
A. 15 degrees
B. 45–90 degrees
C. 120 degrees
D. 10 degrees
Answer: B. 45–90 degrees
Rationale: Subcutaneous injection requires a 45–90° angle depending on patient size.
Question 92
A nurse finds that a patient’s blood sugar is 55 mg/dL. The first action should be:
A. Call the physician
B. Give 15 grams of glucose
C. Administer long-acting insulin
D. Start IV fluids immediately
Answer: B. Give 15 grams of glucose
Rationale: The “Rule of 15” — give 15 g of glucose, wait 15 minutes, and recheck sugar.
Question 93
Which insulin type mimics the body’s natural basal insulin?
A. Lispro
B. Glargine
C. Regular
D. NPH
Answer: B. Glargine
Rationale: Glargine provides a steady, peakless release similar to physiologic basal insulin.
Question 94
Which of the following should the nurse teach a patient using insulin pens?
A. Always prime before injection
B. Store in freezer
C. Use any needle type
D. Shake pen vigorously before use
Answer: A. Always prime before injection
Rationale: Priming removes air and ensures accurate dosing.
Question 95
A nurse notes lipohypertrophy on a patient’s abdomen. The nurse should:
A. Continue injections in the same spot
B. Switch injection site
C. Use a longer needle
D. Stop insulin therapy
Answer: B. Switch injection site
Rationale: Avoiding the affected area allows tissue healing and consistent absorption.
Question 96
A patient taking insulin develops confusion and diaphoresis while waiting for lunch. What should the nurse do?
A. Offer orange juice immediately
B. Give glucagon injection
C. Call physician
D. Start IV insulin
Answer: A. Offer orange juice immediately
Rationale: Fast-acting carbohydrates treat mild hypoglycemia quickly.
Question 97
When should a nurse check for peak insulin action to prevent hypoglycemia?
A. During insulin onset
B. During peak activity
C. During insulin duration
D. Before bedtime
Answer: B. During peak activity
Rationale: Monitoring at insulin peak ensures early detection of hypoglycemia.
Question 98
Which insulin has the longest duration of action?
A. Lispro
B. Regular
C. NPH
D. Degludec
Answer: D. Degludec
Rationale: Insulin degludec lasts up to 42 hours, offering ultra-long glucose control.
Question 99
A nurse observes a patient mixing cloudy and clear insulin. Which action indicates correct technique?
A. Rolling cloudy insulin gently
B. Drawing cloudy insulin first
C. Shaking both vials
D. Mixing insulins in the cloudy vial
Answer: A. Rolling cloudy insulin gently
Rationale: Rolling NPH mixes particles evenly without air bubbles.
Question 100
The nurse knows that insulin overdose primarily causes:
A. Hyperglycemia
B. Hypoglycemia
C. Ketosis
D. Dehydration
Answer: B. Hypoglycemia
Rationale: Excess insulin lowers blood sugar excessively, leading to hypoglycemia.
1. Quick Reference Table: Insulin Types, Onset, Peak, Duration
| Insulin Type | Examples | Onset | Peak | Duration | Key Notes |
|---|---|---|---|---|---|
| Rapid-acting | Lispro, Aspart, Glulisine | 10–15 min | 1–2 hrs | 3–5 hrs | Take with meals; prevents post-meal spikes |
| Short-acting | Regular (Humulin R, Novolin R) | 30–60 min | 2–4 hrs | 5–8 hrs | Only insulin type given IV |
| Intermediate | NPH (Humulin N, Novolin N) | 1–2 hrs | 4–12 hrs | 12–18 hrs | Cloudy; roll gently before use |
| Long-acting | Glargine (Lantus), Detemir (Levemir) | 1–4 hrs | None | 24 hrs | Do not mix with other insulins |
| Ultra-long-acting | Degludec (Tresiba) | 1 hr | None | Up to 42 hrs | Provides steady basal coverage |
💡 Tip for students: Remember the mnemonic “Rapid Short Nerds Love Dogs”
→ Rapid, Short, NPH, Long, Degludec — order of insulin duration.
🧠 NCLEX Tip:
Always match insulin type with meal timing.
Rapid-acting = Eat immediately 🍽️
Short-acting = Eat within 30 min ⏰
Long-acting = Basal control 🌙
- 👉 NCLEX Diabetes Management Practice Questions
- 👉 NCLEX Endocrine System Practice Questions
- 👉 NCLEX Medication Calculation Questions
🧭 Conclusion
Insulin administration is one of the most tested and high-risk areas in nursing practice. Mastering these NCLEX-style questions helps future nurses prevent medication errors and provide safe, evidence-based care to diabetic patients.
From understanding insulin types and mixing rules to recognizing hypoglycemia symptoms and timing doses with meals, these 100 questions offer the complete preparation experience you need.
Effective insulin management goes beyond memorization — it’s about clinical reasoning, patient education, and nursing safety principles. By revising these scenarios regularly, you strengthen both your test performance and real-world nursing confidence.