Hematology questions, especially transfusion reactions, test fast, high-stakes judgment. Work through these 10 practice questions on transfusion-reaction recognition and first actions, anemias, sickle cell crisis, heparin-induced thrombocytopenia, and bleeding precautions, each with a full rationale that explains why every option is right or wrong.
Hematology & Transfusion: Reactions, Anemias & Bleeding
Transfusion safety is the single highest-yield hematology topic on the NCLEX. Verify the client and unit with a second qualified person, obtain baseline vital signs, start slowly, and stay at the bedside for the first 15 minutes because acute hemolytic (ABO-incompatibility) reactions usually appear early. Infuse blood only with 0.9% normal saline and complete each unit within 4 hours. For ANY suspected reaction the first action is always the same: STOP the transfusion. Then keep the vein open with normal saline using NEW tubing (never push the remaining blood in), recheck the client/unit identification, take vital signs, and notify the provider and blood bank. Learn to distinguish the reactions: acute hemolytic (fever, chills, low back/flank pain, hypotension, dark hemoglobinuria, DIC/renal-failure risk) is the most dangerous; febrile non-hemolytic (fever/chills) is the most common and is prevented with leukocyte-reduced products; allergic (hives/itching) responds to antihistamines while anaphylaxis (wheezing, hypotension, IgA-deficient recipients) needs epinephrine; TACO (dyspnea, hypertension, crackles, JVD) is volume overload; TRALI is acute hypoxemia with noncardiogenic pulmonary edema within about 6 hours.
Anemia management hinges on the cause. In iron-deficiency (microcytic) anemia, iron is best absorbed on an empty stomach with vitamin C, taken through a straw for liquid forms, and produces harmless dark or black stools. Pernicious anemia (B12 deficiency from lack of intrinsic factor) requires LIFELONG B12 injections and can cause neurologic deficits. Folic-acid deficiency responds to diet and oral folate, while aplastic anemia produces pancytopenia with infection and bleeding risk.
Bleeding disorders share a precautions bundle: soft toothbrush, electric razor, no IM injections/rectal temps/suppositories, fall precautions, and no aspirin/NSAIDs. Know the emergencies: heparin-induced thrombocytopenia (HIT) is a platelet drop with paradoxical clotting days into heparin—stop ALL heparin and switch to a non-heparin anticoagulant; DIC is simultaneous clotting and bleeding treated by fixing the underlying cause; sickle cell crisis needs hydration, oxygen, and scheduled opioids; hemophilia needs factor replacement.
For every reaction’s timing, signs, and first action in one table, see our blood transfusion reactions guide.
Hematology & Transfusion NCLEX Practice Questions
Question 1 · Transfusion reactions
Ten minutes into a unit of packed red blood cells, a client reports low back pain and chills. The nurse notes a temperature increase, blood pressure of 88/50 mm Hg, and pink-tinged urine in the catheter bag. What is the nurse's FIRST action?
- A Slow the transfusion rate and continue to monitor the client's vital signs closely
- B Stop the transfusion and keep the vein open with normal saline via new tubing
- C Administer the ordered antihistamine and antipyretic, then reassess the client
- D Notify the blood bank and the provider of a suspected transfusion reaction
Show answer & rationale
Correct answer: B
This picture (early onset, fever, chills, low back/flank pain, hypotension, hemoglobinuria) is a classic acute hemolytic reaction from ABO incompatibility, the most dangerous transfusion reaction. For ANY suspected reaction the first action is to STOP the transfusion so no additional incompatible blood enters the circulation. Stopping alone is not enough: the nurse disconnects the blood tubing and keeps the vein open with 0.9% normal saline through NEW tubing so the line stays patent for emergency drugs and fluids without infusing more of the offending unit. Slowing the transfusion and continuing to monitor is wrong and dangerous because it keeps delivering incompatible cells that drive hemolysis, DIC, and acute renal failure. Giving an antihistamine and antipyretic treats symptoms but does not address the immediate threat and is not the first action; antihistamines are appropriate for mild allergic reactions, not hemolysis. Notifying the blood bank and provider is essential and comes soon, but only AFTER the transfusion is stopped and the line is maintained with saline, vitals are taken, and the client is protected. Memory aid: for a reaction, think STOP the blood, START the saline (new tubing), then assess and notify. Normal saline is the only fluid ever hung with blood because dextrose causes hemolysis and calcium-containing solutions like lactated Ringer's promote clotting.
Question 2 · Transfusion reactions
A client develops fever, shaking chills, flank pain, hypotension, and dark red-brown urine approximately 15 minutes after a transfusion is started. Which type of transfusion reaction does the nurse suspect?
- A Febrile non-hemolytic reaction
- B Mild allergic reaction
- C Transfusion-associated circulatory overload (TACO)
- D Acute hemolytic reaction from ABO incompatibility
Show answer & rationale
Correct answer: D
The combination of early onset (within the first 15 minutes), fever with chills, flank/low back pain, hypotension, and dark hemoglobinuria is the hallmark of an acute hemolytic reaction caused by ABO incompatibility. Recipient antibodies attack transfused red cells, releasing free hemoglobin that spills into the urine and can trigger disseminated intravascular coagulation (DIC) and acute renal failure, so it is a medical emergency. A febrile non-hemolytic reaction is the most common reaction and causes fever and chills, but it does NOT cause flank pain, hypotension, or hemoglobinuria; it is uncomfortable rather than life-threatening and is reduced by leukocyte-reduced products. A mild allergic reaction presents with urticaria (hives) and itching, sometimes flushing, without fever, back pain, or dark urine, and responds to antihistamines. TACO is circulatory overload from too much volume infused too fast and presents with dyspnea, hypertension, crackles, and jugular vein distention, not fever with hemoglobinuria. Clinical pearl: red or dark urine plus back pain in the first minutes of a transfusion equals hemolysis until proven otherwise, prompting an immediate stop and blood bank notification. Rechecking the client identification and unit label against the crossmatch is a priority because most ABO reactions stem from clerical mismatch, and the blood bag and tubing must be returned to the lab for analysis.
Question 3 · Transfusion reactions
Thirty minutes into the second unit of packed red blood cells, an 82-year-old client with heart failure develops dyspnea, bilateral crackles, jugular vein distention, and a blood pressure of 186/94 mm Hg. Which set of interventions is most appropriate?
- A Stop the transfusion, sit the client upright, and give a prescribed diuretic
- B Stop the transfusion and prepare to administer intramuscular epinephrine
- C Continue the transfusion at the ordered rate and administer an antihistamine
- D Lay the client flat, apply warm blankets, and increase the blood infusion rate
Show answer & rationale
Correct answer: A
Dyspnea, crackles, jugular vein distention, and hypertension during transfusion, especially in an older adult with heart failure receiving multiple units, indicate transfusion-associated circulatory overload (TACO)—too much volume delivered too quickly. The nurse stops the transfusion, sits the client upright to ease breathing and reduce venous return, and anticipates a diuretic such as furosemide plus oxygen to relieve the fluid overload. Stopping and giving intramuscular epinephrine treats anaphylaxis (wheezing, hypotension, airway swelling in an IgA-deficient recipient), which does not fit hypertension with JVD and crackles; epinephrine would worsen this hypertensive, overloaded client. Continuing the transfusion and giving an antihistamine is wrong: an antihistamine treats allergic hives, not overload, and continuing the unit keeps adding volume to failing circulation. Laying the client flat, warming, and increasing the rate is exactly wrong: flat positioning worsens pulmonary congestion and a faster rate increases overload. Clinical pearl: TACO = Too much, too fast; think upright, oxygen, and diuretics. To prevent it in at-risk clients, transfuse slowly (over the full allowable time up to 4 hours), consider divided/smaller units, and monitor lung sounds and vital signs closely. TRALI, by contrast, causes hypoxemia with noncardiogenic pulmonary edema and is typically normotensive-to-hypotensive within about 6 hours.
Question 4 · Anemias
The nurse is teaching a client newly diagnosed with pernicious anemia caused by a lack of intrinsic factor. Which statement by the client indicates correct understanding of the treatment plan?
- A I will take an oral vitamin B12 tablet with breakfast every morning
- B Increasing red meat and leafy greens in my diet will correct this within a month
- C I will need vitamin B12 injections for the rest of my life
- D Once my blood counts improve, I can stop the vitamin B12 completely
Show answer & rationale
Correct answer: C
Pernicious anemia results from a lack of intrinsic factor (often from autoimmune gastric parietal-cell destruction), and without intrinsic factor dietary vitamin B12 cannot be absorbed in the terminal ileum. Therefore B12 must bypass the gut, requiring LIFELONG intramuscular (or deep subcutaneous) B12 injections; high-dose intranasal forms exist but the safe, testable teaching is that replacement is lifelong. A standard oral B12 tablet with breakfast is not reliable for classic pernicious anemia because normal absorption fails without intrinsic factor; high-dose oral B12 is used only for select clients under provider direction, so the expected teaching is lifelong injections. Relying on diet (red meat and leafy greens) is wrong on two counts: B12 comes from animal products, not leafy greens (those supply folate), and no amount of dietary intake helps when the absorption mechanism is missing. Believing the client can stop B12 once counts improve is dangerous because the underlying absorption defect is permanent; stopping causes the anemia and, importantly, neurologic damage to recur. Clinical pearl: B12 deficiency uniquely causes neurologic signs—paresthesias, ataxia, and impaired proprioception—that can become irreversible, so treatment is not optional. Monitor for these neuro findings and emphasize adherence. Contrast with folic-acid deficiency anemia, which IS corrected with diet and oral folate, and iron-deficiency anemia (microcytic), which responds to oral iron.
Question 5 · Anemias
A client is prescribed oral ferrous sulfate for iron-deficiency anemia. Which statement by the client indicates that teaching has been effective?
- A I should take my iron with milk or an antacid to protect my stomach
- B If my stools turn black, I will stop the iron and call the clinic
- C Taking iron with my morning coffee will help it work better
- D I will take the iron between meals with a glass of orange juice
Show answer & rationale
Correct answer: D
Oral iron is absorbed best in an acidic environment on an empty stomach, so taking it between meals with a source of vitamin C such as orange juice maximizes absorption—vitamin C reduces iron to its more absorbable ferrous form. If GI upset occurs it may be taken with a small amount of food, but the ideal teaching is empty stomach plus vitamin C. Taking iron with milk or an antacid is wrong because calcium and antacids raise gastric pH and bind iron, sharply reducing absorption. Stopping the iron because stools turn black is incorrect: dark green or black stools are an EXPECTED, harmless effect of oral iron and are not a reason to stop; the nurse should reassure the client, but teach that sticky, tarry stools or visible blood can signal GI bleeding and must be reported. Taking iron with coffee is also wrong because tannins in coffee and tea inhibit iron absorption. Additional pearls: liquid iron should be diluted and taken through a straw to prevent staining the teeth, and clients should increase dietary iron (lean red meat, beans, fortified cereals, dark leafy greens) and fiber/fluids to counter iron-induced constipation. Iron-deficiency anemia is microcytic and hypochromic; expect improvement in reticulocytes within about a week, but continue therapy for several months to rebuild iron stores.
Question 6 · Heparin-induced thrombocytopenia
A client receiving IV heparin for a deep vein thrombosis has a platelet count that has dropped from 250,000/mcL to 90,000/mcL on day 6 of therapy, and now reports a new, cool, mottled left foot. Which action does the nurse anticipate?
- A Administering a platelet transfusion to correct the low count
- B Stopping all heparin and initiating a non-heparin anticoagulant
- C Increasing the heparin infusion to treat the new clot
- D Continuing heparin and rechecking the platelet count in 24 hours
Show answer & rationale
Correct answer: B
A platelet drop of roughly 50% or more occurring about 5 to 10 days into heparin therapy, combined with a NEW thrombosis (the cool, mottled foot), is the hallmark of heparin-induced thrombocytopenia (HIT), an immune-mediated reaction in which antibodies activate platelets and cause paradoxical clotting despite the low platelet count. The correct action is to STOP ALL heparin immediately—including flushes and low-molecular-weight heparin—and start a non-heparin anticoagulant such as argatroban or a direct oral anticoagulant to prevent further limb- and life-threatening clots. Giving a platelet transfusion is generally avoided because adding platelets can fuel more clotting; platelets are reserved for active bleeding or a high-bleeding-risk procedure, and HIT does not typically cause bleeding. Increasing the heparin infusion is exactly the wrong move: heparin is the trigger, so more heparin worsens the antibody-driven thrombosis. Continuing heparin and rechecking in 24 hours delays essential treatment and allows the clot to extend, risking amputation or pulmonary embolism. Clinical pearl: in HIT, the danger is CLOTTING, not bleeding—remember 'HIT clots,' and the treatment is to remove all heparin and anticoagulate with a non-heparin agent. Monitor platelet counts on any client receiving heparin, and document a heparin allergy/HIT flag so heparin is avoided in the future.
Question 7 · Sickle cell crisis
An adult client is admitted in a vaso-occlusive (sickle cell) crisis with severe generalized pain. Which combination of interventions should the nurse prioritize?
- A Provide IV hydration, oxygen, and scheduled opioid analgesia
- B Encourage ambulation and give acetaminophen as needed for pain
- C Restrict oral fluids and apply cold packs to painful joints
- D Place the client in a cool room and withhold opioids to prevent dependence
Show answer & rationale
Correct answer: A
Vaso-occlusive crisis occurs when sickled cells obstruct microcirculation, causing ischemia and severe pain. The core bundle is HYDRATION (oral fluids, or IV fluids if the client cannot drink, to reduce blood viscosity; once the client is euvolemic, IV fluids run at no more than maintenance rate to avoid fluid overload), OXYGEN when saturation is below 95% on room air because hypoxia worsens sickling, and adequate PAIN control with opioids given around the clock (scheduled or PCA), because crisis pain is severe and undertreated pain is a common failure. Restricting fluids and applying cold packs is harmful: dehydration promotes more sickling, and cold causes vasoconstriction that intensifies the occlusion and pain—warmth, not cold, is applied. Encouraging ambulation with only as-needed acetaminophen underestimates the pain; mild PRN analgesia is inadequate for a true crisis, although ambulation and activity are encouraged as soon as possible to lower acute chest syndrome risk. Placing the client in a cool room and withholding opioids to prevent dependence reflects a dangerous myth; cold triggers sickling, and fear of addiction should never justify undertreating documented crisis pain. Clinical pearl for avoiding triggers—remember the crisis triggers as cold, dehydration, hypoxia, high altitude, infection, and stress. Monitor for complications such as acute chest syndrome (fever, chest pain, hypoxia), and provide incentive spirometry and infection prevention. Hydroxyurea is a maintenance therapy that raises fetal hemoglobin and reduces crisis frequency but is not the acute crisis treatment.
Question 8 · Transfusion reactions
A client shows signs of a suspected transfusion reaction shortly after a unit of packed red blood cells is started. Which actions should the nurse take? Select all that apply.
- A Continue the transfusion at a slower rate while monitoring the client
- B Stop the transfusion immediately
- C Obtain the client's vital signs
- D Recheck the client identification against the blood unit label
- E Disconnect the blood tubing and infuse 0.9% normal saline with new tubing to keep the vein open
- F Notify the provider and the blood bank
Show answer & rationale
Correct answer: B, C, D, E, F
For any suspected transfusion reaction the priority sequence is protective and immediate. STOP the transfusion first so no additional potentially incompatible blood enters the circulation. Next, DISCONNECT the blood tubing and hang 0.9% normal saline with NEW tubing to keep the vein open—this maintains IV access for emergency fluids/medications without pushing the remaining blood in the old line into the client. OBTAIN vital signs to gauge severity and trend the reaction, comparing them to the required baseline set. NOTIFY the provider and the blood bank so orders can be given and the unit/tubing can be returned for analysis; the blood bank must investigate every reaction. RECHECK the client identification against the unit label and crossmatch, because most severe acute hemolytic reactions result from clerical identification errors. Continuing the transfusion at a slower rate is the one action that is unsafe and must NOT be selected: any continued infusion keeps delivering the offending blood and can escalate a hemolytic reaction to DIC, shock, and renal failure. Clinical pearl: STOP, SALINE (new line), then assess and notify—slowing down is never acceptable once a reaction is suspected. Documentation should include the time, symptoms, vital signs, volume infused, and interventions, and a urine specimen and the blood bag are typically sent to the lab.
Question 9 · Bleeding precautions
A client with severe thrombocytopenia (platelet count 18,000/mcL) requires bleeding precautions. Which interventions should the nurse include in the plan of care? Select all that apply.
- A Implement fall and injury precautions
- B Avoid intramuscular injections whenever possible
- C Administer aspirin for headache or minor discomfort
- D Use a soft-bristled toothbrush for oral care
- E Avoid rectal temperatures and suppositories
- F Shave with an electric razor rather than a blade
Show answer & rationale
Correct answer: A, B, D, E, F
Bleeding precautions minimize any source of tissue trauma when platelets are dangerously low. A SOFT-bristled toothbrush prevents gum bleeding, and an ELECTRIC razor prevents nicks from a blade. AVOIDING intramuscular injections prevents deep-tissue bleeding and hematomas; when injections are unavoidable, use the smallest gauge and hold prolonged pressure. AVOIDING rectal temperatures and suppositories prevents trauma to the fragile, vascular rectal mucosa that can cause significant bleeding. Implementing FALL and injury precautions is essential because minor bumps can cause serious bleeding, including intracranial hemorrhage. Administering aspirin is the action that must NOT be selected: aspirin (and NSAIDs) inhibit platelet function and dramatically increase bleeding risk, so acetaminophen is the preferred analgesic/antipyretic in thrombocytopenic clients. Additional measures include avoiding flossing vigorously, blowing the nose forcefully, and using stool softeners to prevent straining, plus applying prolonged pressure to any puncture site. Clinical pearl: think 'nothing sharp, nothing rectal, nothing that thins the blood.' These same precautions apply broadly to bleeding disorders such as ITP, DIC, hemophilia, and clients on anticoagulants. Monitor for petechiae, ecchymosis, gum/nasal bleeding, blood in stool or urine, and neurologic changes that may signal intracranial bleeding, and report a further drop in platelets promptly.
Question 10 · Transfusion reactions
The nurse is monitoring for an acute hemolytic transfusion reaction. Which findings would support this diagnosis? Select all that apply.
- A Bounding hypertension with jugular vein distention
- B Low back or flank pain
- C Dark or red-tinged urine (hemoglobinuria)
- D Isolated hives and itching with no other symptoms
- E Fever and chills
- F Hypotension
Show answer & rationale
Correct answer: B, C, E, F
An acute hemolytic reaction from ABO incompatibility is driven by rapid destruction of transfused red cells, and its findings typically begin within the first 15 minutes. FEVER and CHILLS reflect the systemic inflammatory response. LOW BACK or FLANK PAIN is a classic early clue, related to renal involvement as free hemoglobin is filtered. HYPOTENSION signals developing shock as hemolysis and cytokine release progress. DARK or RED-TINGED URINE (hemoglobinuria) results from free hemoglobin spilling into the urine and is a red-flag sign that also warns of impending acute kidney injury. Isolated hives and itching WITHOUT other symptoms is NOT hemolysis—that describes a mild allergic reaction, which is treated by stopping the transfusion and giving antihistamines. Bounding hypertension with jugular vein distention is NOT hemolysis either; that pattern, along with dyspnea and crackles, indicates TACO (circulatory overload)—note that hemolytic reactions cause HYPOtension, not hypertension. Clinical pearl: the ominous triad of fever/chills, flank or low back pain, and dark urine early in a transfusion means STOP the blood now, because acute hemolytic reactions can rapidly progress to DIC, shock, and renal failure. Send the blood bag, tubing, and a urine and blood specimen to the lab, monitor urine output closely, and support renal perfusion with normal saline as ordered.
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Hematology & Transfusion FAQ
What is the first thing a nurse should do for a suspected transfusion reaction?
Stop the transfusion immediately. Then keep the vein open with 0.9% normal saline using new tubing (do not infuse the remaining blood), take vital signs, recheck the client and unit identification, and notify the provider and blood bank. Never just slow the rate—any continued infusion keeps delivering the offending blood.
How do I tell an acute hemolytic reaction apart from TACO and an allergic reaction?
Acute hemolytic (ABO incompatibility) starts early with fever, chills, low back/flank pain, hypotension, and dark hemoglobinuria—the most dangerous reaction. TACO is volume overload with dyspnea, hypertension, crackles, and JVD. A mild allergic reaction is just hives and itching. Anaphylaxis adds wheezing and hypotension and needs epinephrine.
Why do pernicious anemia clients need B12 injections instead of pills?
Pernicious anemia is caused by a lack of intrinsic factor, so dietary B12 is very poorly absorbed through the normal pathway, which is why B12 injections are the standard, reliable route. (High-dose oral B12 is an accepted maintenance alternative for select clients.) Because the absorption defect is permanent, therapy is lifelong, and untreated B12 deficiency causes irreversible neurologic damage.
What is HIT and why can't you give platelets for it?
Heparin-induced thrombocytopenia is an immune reaction, usually 5–10 days into heparin, where platelets drop and paradoxical clotting occurs. Stop ALL heparin and start a non-heparin anticoagulant. Platelet transfusions are generally avoided unless the client is actively bleeding, because adding platelets can fuel more clotting—the danger in HIT is thrombosis, not bleeding.