CCRN Practice Test

CCRN Endocrine & Hematology/Immunology Practice Questions

Endocrine & Hematology/Immunology makes up 5 of every 50 questions on a Tigertest CCRN practice test. Here are 10 of the 20 questions on it, each with the answer and the reason.

Updated 2026-11-14 by the Tigertest team. Based on the AACN Adult CCRN test plan. Original questions; 50 per test, weighted like the real exam. Not affiliated with AACN or AACN Certification Corporation.

1. 1. Under the 2024 consensus report on hyperglycemic crises, which result confirms the ketosis needed to diagnose DKA?

   • A.A glucose of 600 mg/dL or more
   • B.Beta-hydroxybutyrate of 3.0 mmol/L
   • C.Trace ketones on a urine dipstick
   • D.A serum lactate of 2.0 mmol/L

   Answer: B. The 2024 ADA-led consensus diagnoses DKA from hyperglycemia (or known diabetes), blood beta-hydroxybutyrate of at least 3.0 mmol/L and metabolic acidosis. A glucose of 600 mg/dL or more is typical of HHS, and urine ketones are a weaker marker.

2. 2. A patient with DKA is about to start an insulin infusion. Which result means insulin must wait?

   • A.Glucose 480 mg/dL
   • B.Potassium 5.4 mmol/L
   • C.Sodium 131 mmol/L
   • D.Potassium 3.2 mmol/L

   Answer: D. Insulin drives potassium into cells, so when potassium is below 3.5 mmol/L it is replaced first and insulin is delayed until it rises above 3.5. A high potassium on arrival is common in DKA and falls once insulin starts.

3. 3. During DKA treatment, at what glucose level is dextrose added to the IV fluids?

   • A.Below 250 mg/dL
   • B.Below 70 mg/dL
   • C.Below 400 mg/dL
   • D.Below 150 mg/dL

   Answer: A. Once glucose falls below 250 mg/dL, 5 to 10% dextrose is added and the insulin rate is usually halved to 0.05 units/kg/h, so insulin can keep clearing ketones without causing hypoglycemia.

4. 4. Which result shows that DKA has resolved under the 2024 consensus criteria?

   • A.A negative urine ketone test
   • B.A glucose below 250 mg/dL
   • C.Ketones under 0.6, pH 7.3 or more
   • D.An anion gap of 14 mmol/L alone

   Answer: C. Resolution is plasma ketones below 0.6 mmol/L with venous pH at least 7.3 or bicarbonate at least 18 mmol/L. The consensus advises against relying on the anion gap or urine ketones, and glucose falls well before ketosis clears.

5. 5. A patient has hyperosmolar hyperglycemic state with no significant ketonemia or acidosis. At what rate does the insulin infusion usually start?

   • A.0.5 units/kg/h
   • B.0.1 units/kg/h
   • C.0.05 units/kg/h
   • D.0.01 units/kg/h

   Answer: C. The 2024 consensus suggests 0.05 units/kg/h in HHS without ketosis, after fluid resuscitation has begun, because fluids alone lower glucose a great deal. The 0.1 units/kg/h rate is the DKA and mixed DKA/HHS dose.

6. 6. A patient with small cell lung cancer has a sodium of 121 mmol/L, low serum osmolality and concentrated urine, and is clinically euvolemic. Which treatment fits?

   • A.Fluid restriction
   • B.A D5W infusion
   • C.Free water flushes
   • D.Desmopressin

   Answer: A. This is SIADH: too much ADH holds water, diluting the serum while the urine stays concentrated. Water restriction is first-line, with hypertonic saline for severe symptoms; desmopressin and free water would lower the sodium further.

7. 7. After pituitary surgery, a patient's urine output is 400 mL/h with a specific gravity of 1.002 and a serum sodium of 152 mmol/L. Which treatment should the nurse expect?

   • A.IV furosemide
   • B.3% saline
   • C.Fluid restriction
   • D.Desmopressin

   Answer: D. Large volumes of dilute urine with a rising sodium after pituitary or head injury mean central diabetes insipidus. Desmopressin replaces ADH, with fluids to match output; restricting fluid would worsen the hypernatremia.

8. 8. A patient on long-term prednisone has refractory hypotension, a sodium of 128, a potassium of 5.8 and a glucose of 54 after surgery. Which drug is given first?

   • A.Oral fludrocortisone
   • B.IV hydrocortisone
   • C.IV regular insulin
   • D.IV levothyroxine

   Answer: B. Hypotension that resists fluids and pressors with hyponatremia, hyperkalemia and hypoglycemia suggests adrenal crisis, which is treated with IV hydrocortisone and fluids with dextrose. Long-term steroids suppress the adrenal response to surgical stress.

9. 9. Which finding fits myxedema coma?

   • A.A temperature over 39 °C
   • B.Hypothermia
   • C.Marked tachycardia
   • D.Severe hypercalcemia

   Answer: B. Severe hypothyroidism slows metabolism: hypothermia, bradycardia, hypoventilation, hyponatremia and a depressed level of consciousness. Fever and tachycardia point instead to thyroid storm.

10. 10. In thyroid storm, how are a thionamide and iodine given?

    • A.Iodine first, then thionamide
    • B.Iodine alone, no thionamide
    • C.Levothyroxine before both
    • D.Thionamide first, then iodine

    Answer: D. A thionamide such as propylthiouracil or methimazole is given first, then iodine at least an hour later, because iodine given first can feed new hormone synthesis. Beta blockers, steroids and cooling are given too.