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NCLEX lab values practice questions

20 free NCLEX-style lab values questions: hemoglobin and transfusions, kidney and liver function, drug levels, clotting tests, neutrophil and platelet counts, and what the nurse does about an abnormal result.

Tap an answer to check it, or open "Show the answer and rationale" under each question. Every client is fictional. For exam practice only, not medical advice.

Question 1 of 20

A nurse reviews the morning laboratory results for four clients. Which client's result requires follow-up first?

  1. Has COPD: hematocrit 54%, unchanged from last month's result
  2. Has chronic kidney disease: potassium 5.3 mEq/L, up from 4.9
  3. Taking warfarin: INR 3.6, goal 2 to 3, with no signs of bleeding
  4. Receiving chemotherapy: platelets 16,000/mm³ and a new severe headache
Show the answer and rationale

Answer: D

A platelet count below about 20,000/mm³ carries a risk of spontaneous bleeding, and a new severe headache in that setting may signal bleeding inside the skull, so this client is assessed and the provider is notified first. An INR of 3.6 above its goal also needs follow-up, but with no bleeding it is usually handled by holding or lowering the warfarin dose, while the headache suggests bleeding that may already be happening. A potassium of 5.3 mEq/L is a mild rise common in chronic kidney disease, and a high hematocrit is an expected adaptation to chronic hypoxemia in COPD.

📚 Learn it: The CBC: Hemoglobin, White Cells and Platelets

Question 2 of 20

An 88-year-old woman who weighs 99 lb (45 kg) is admitted from a nursing home with pneumonia. Her serum creatinine is 1.1 mg/dL. A nursing student says the client's kidney function must be normal because the creatinine is within the reference range. Which response by the nurse is accurate?

  1. 'With her low muscle mass, she makes less creatinine, so her eGFR may be low.'
  2. 'Yes, a creatinine below 1.2 mg/dL shows that her kidneys are filtering normally.'
  3. 'The BUN reflects kidney function better than creatinine does in older adults.'
  4. 'Creatinine rises with age, so her true value is likely lower than 1.1 mg/dL.'
Show the answer and rationale

Answer: A

Creatinine comes from muscle, so a frail older adult with little muscle mass makes less of it, and a value that looks normal can hide a markedly reduced filtration rate; for an 88-year-old woman, a creatinine of 1.1 mg/dL corresponds to an eGFR of about 49 mL/min/1.73 m². The nurse relies on the eGFR, which adjusts for age and sex, when checking doses of drugs the kidneys clear. Accepting the creatinine as proof of normal function is the common error. BUN is less specific, because it also rises with dehydration, bleeding and protein intake, and creatinine production falls rather than rises as muscle is lost with age.

📚 Learn it: BUN, Creatinine, Glucose and the Kidney Ratio

Question 3 of 20

A 34-year-old client with no history of liver disease is hospitalized for vomiting and dehydration on day 6 of acute hepatitis A. The nurse reviews today's findings. Which finding requires immediate follow-up?

  1. Total bilirubin 5.1 mg/dL with yellow sclerae and itching
  2. INR 2.2, up from 1.3 yesterday, and the client cannot name the month
  3. Dark, tea-colored urine and marked fatigue
  4. ALT 1,850 units/L, up from 1,420 units/L yesterday
Show the answer and rationale

Answer: B

A rising INR with new confusion in a client without prior liver disease meets the definition of acute liver failure: coagulopathy with an INR of 1.5 or more plus any degree of encephalopathy. It can progress quickly to cerebral edema, so the nurse reports it at once and anticipates intensive care and early contact with a transplant center. The rising ALT is the runner-up because the number is striking, but aminotransferases reflect liver cell injury, not liver function, and their changes correlate poorly with prognosis. Jaundice, itching, dark urine and fatigue are expected findings in acute hepatitis A.

📚 Learn it: Troponin, BNP, Liver Enzymes and Lactate

Question 4 of 20

A client with bipolar disorder takes lithium carbonate 600 mg at 0800 and 2000. The provider orders a serum lithium level for the next day. Which instruction should the nurse give the client?

  1. 'Skip the 2000 dose tonight so the result is not falsely high.'
  2. 'Drink extra water tonight so the sample is not too concentrated.'
  3. 'Have the blood drawn in the morning before you take your 0800 dose.'
  4. 'Take your 0800 dose as usual, then have the blood drawn 2 hours later, when the level peaks.'
Show the answer and rationale

Answer: C

Lithium levels are drawn as a trough, 8 to 12 hours after the last dose and just before the next one, because the therapeutic range of about 0.6 to 1.2 mEq/L and dosing decisions are based on that timing; with doses at 0800 and 2000, a draw before the morning dose falls about 12 hours after the evening dose. A draw 2 hours after a dose is the runner-up because it sounds precise, but it catches the absorption peak and reads falsely high. Skipping a dose falsely lowers the result, and extra water moves the level away from its usual steady state.

📚 Learn it: Therapeutic Drug Levels and the Clotting Tests

Question 5 of 20

Urine cultures for four clients each grow 100,000 CFU/mL or more of Escherichia coli. None of the clients has dysuria, flank pain or fever. Which client should the nurse expect to receive antibiotic treatment?

  1. A 26-year-old at 12 weeks' gestation seen for her first prenatal visit
  2. A 64-year-old with type 2 diabetes seen for a routine annual checkup
  3. A 70-year-old with a long-term indwelling catheter for urinary retention
  4. A 78-year-old in long-term care with new confusion and stable vital signs
Show the answer and rationale

Answer: A

Asymptomatic bacteriuria is screened for early in pregnancy and treated, because untreated bacteriuria in pregnancy often progresses to pyelonephritis (IDSA 2019). The older adult with new confusion is the tempting choice, but without fever, unstable vital signs or urinary symptoms, the IDSA advises looking for other causes of the delirium and observing rather than treating the bacteria. Clients with diabetes or a long-term catheter are not screened or treated, because treatment has not been shown to prevent symptomatic infection and adds adverse effects and antibiotic resistance.

📚 Learn it: Urinalysis, Specific Gravity and Collecting It Right

Question 6 of 20 · Select all that apply

A client with aplastic anemia has a platelet count of 18,000/mm³. Which actions should the nurse include in the plan of care? Select all that apply.

  1. Offer acetaminophen rather than ibuprofen for mild joint pain
  2. Massage subcutaneous injection sites to help absorption
  3. Have the client use an electric razor for shaving
  4. Hold pressure on venipuncture sites for at least 5 minutes
  5. Give a bisacodyl suppository if constipation develops
  6. Encourage flossing twice daily to prevent gum infection
Show the answer and rationale

Answer: A, C, D

A platelet count below 20,000/mm³ carries a risk of spontaneous bleeding, so care avoids trauma and drugs that impair platelets. An electric razor avoids nicks, pressure held for 5 minutes or longer seals puncture sites, and acetaminophen relieves pain without the antiplatelet effect of ibuprofen and other NSAIDs. Rectal suppositories, enemas and rectal temperatures can tear the fragile rectal mucosa, so constipation is prevented with oral stool softeners instead. Flossing makes the gums bleed and is replaced with a soft toothbrush or sponge, and massaging an injection site increases bruising.

📚 Learn it: The CBC: Hemoglobin, White Cells and Platelets

Question 7 of 20

A client admitted with black, tarry stools has a hemoglobin of 6.9 g/dL and receives 2 units of packed red blood cells. A hemoglobin drawn 1 hour after the second unit is 7.2 g/dL. The blood pressure is 112/70 mm Hg and the heart rate 96 beats/min. Which action should the nurse take?

  1. Request a third unit to raise the hemoglobin above 9 g/dL
  2. Report the small rise and assess for ongoing bleeding, such as new melena
  3. Recheck the hemoglobin tomorrow, because it takes 24 hours to equilibrate
  4. Document an expected response, since each unit adds about 0.5 g/dL
Show the answer and rationale

Answer: B

In a client who is not bleeding, each unit of packed red cells raises the hemoglobin by about 1 g/dL and the hematocrit by about 3%, so 2 units should bring 6.9 g/dL close to 9 g/dL. A rise of only 0.3 g/dL suggests continued blood loss or destruction of the transfused cells, so the nurse assesses for melena, hematemesis and a rising heart rate and reports the result. Waiting until tomorrow is a common habit, but a hemoglobin drawn as early as 15 minutes after a transfusion matches one drawn 24 hours later. A rise of 0.5 g/dL per unit understates the normal response, and asking for a third unit treats the number before its cause is found.

📚 Learn it: The CBC: Hemoglobin, White Cells and Platelets

Question 8 of 20

A client with type 2 diabetes had a bleeding duodenal ulcer 5 weeks ago and received 4 units of packed red blood cells. Today the hemoglobin A1c is 5.9%, although the client's home log shows fasting and premeal glucose readings of 170 to 260 mg/dL. Which statement by the nurse is accurate?

  1. 'Your meter is likely reading high, since the A1c is the more reliable test.'
  2. 'An A1c of 5.9% shows good control, so your medicine doses can be lowered.'
  3. 'The recent blood loss and transfusion make this A1c read falsely low.'
  4. 'The A1c is accurate; your readings are high because you check after meals.'
Show the answer and rationale

Answer: C

The A1c measures glucose attached to hemoglobin over the 2- to 3-month life of red cells, so recent blood loss and transfusion, which replace the client's older glycated cells with new and donor cells, make it read falsely low. Laboratory guidance advises against relying on the A1c when red cell turnover is altered and suggests glucose readings or a test such as fructosamine, which reflects about 2 to 3 weeks. Blaming the meter is tempting because the A1c is usually the steadier number, but not after red cells have been replaced. A value of 5.9% does not show good control here, and the log consists of fasting and premeal readings, not after-meal checks.

📚 Learn it: BUN, Creatinine, Glucose and the Kidney Ratio

Question 9 of 20

A 58-year-old client received 2 units of packed red blood cells 6 days ago for anemia after surgery. Today the client has a temperature of 100.6°F (38.1°C), yellow sclerae and fatigue. Laboratory results: hemoglobin 7.6 g/dL (9.8 g/dL the day after the transfusion), indirect (unconjugated) bilirubin 3.4 mg/dL, direct bilirubin 0.2 mg/dL, LDH elevated, ALT and alkaline phosphatase normal. Which interpretation is most accurate?

  1. Liver cell injury from a viral hepatitis acquired through the transfusion
  2. An expected bilirubin rise as the transfused red cells reach the end of their life span
  3. Red cell breakdown from a delayed hemolytic transfusion reaction
  4. A blockage of the common bile duct
Show the answer and rationale

Answer: C

A falling hemoglobin with fever, jaundice, a high unconjugated bilirubin and a raised LDH 6 days after a transfusion points to a delayed hemolytic transfusion reaction, in which the client's antibodies destroy the donor red cells, usually between 1 day and 4 weeks later; the nurse reports it and anticipates a direct antiglobulin test and antibody screen before any further transfusion. Transfusion-acquired hepatitis is the runner-up, but it raises ALT and takes weeks to months to appear. A blocked bile duct raises direct bilirubin and alkaline phosphatase, and normal aging of transfused cells does not drop the hemoglobin by 2 g/dL in 5 days.

📚 Learn it: Troponin, BNP, Liver Enzymes and Lactate

Question 10 of 20

A client receiving IV gentamicin every 8 hours has a trough level drawn 30 minutes before the 1400 dose. The result is above the expected range. What should the nurse do?

  1. Redraw the trough before giving the 1400 dose
  2. Hold the 1400 dose and notify the provider
  3. Give the 1400 dose, then report the level to the provider
  4. Hold the 1400 dose and give it at 1800 instead
Show the answer and rationale

Answer: B

A high trough means the drug is not clearing between doses, which raises the risk of kidney injury and permanent hearing loss, so the next dose is held and the provider notified to change the dose or interval. Holding the dose and giving it later sounds safe, but choosing a new interval is the provider's decision, not the nurse's. Giving the full dose and reporting afterward adds drug the client cannot clear, and a correctly timed trough does not need a redraw before acting on it.

📚 Learn it: Therapeutic Drug Levels and the Clotting Tests

Practice 10 more Lab values questions free →

A timed or tutor-mode set in the app, scored by area, with every miss saved for review. Free, no sign-up needed.

Question 11 of 20

A client is admitted with severe community-acquired pneumonia and has a productive cough. Prescriptions include a sputum Gram stain and culture and IV ceftriaxone, due now. Which action should the nurse take first?

  1. Have the client rinse with water, take deep breaths and cough into a sterile cup
  2. Have the client gargle with antiseptic mouthwash and then spit into a sterile cup
  3. Swab the back of the throat and send the swab to the laboratory for culture
  4. Give the ceftriaxone now and collect sputum when the client next coughs some up
Show the answer and rationale

Answer: A

Cultures are collected before the first antibiotic dose whenever this causes no meaningful delay, because antibiotic already in the airway lowers the chance of growing the organism that guides therapy. A client with a productive cough can give a specimen in minutes: rinsing with plain water removes mouth bacteria, and deep breaths followed by a forceful cough bring up secretions from the lower airway. Giving the antibiotic first is tempting because treatment is urgent, but it can leave a culture that grows nothing useful. Antiseptic mouthwash can kill the organisms being cultured, and a throat swab collects saliva and mouth flora, not sputum.

📚 Learn it: Urinalysis, Specific Gravity and Collecting It Right

Question 12 of 20

A nurse reviews the morning hemoglobin results for four hospitalized adults. None of the clients is actively bleeding. For which client should the nurse anticipate a prescription for a red blood cell transfusion?

  1. A 34-year-old with iron deficiency from heavy menses: hemoglobin 8.1 g/dL, no symptoms
  2. A 46-year-old with pneumonia: hemoglobin 7.3 g/dL, heart rate 84 beats/min, no symptoms
  3. A 63-year-old with kidney disease receiving epoetin alfa: hemoglobin 8.8 g/dL, chronic fatigue
  4. A 79-year-old with coronary artery disease, day 1 after hip repair: hemoglobin 7.6 g/dL, new dizziness
Show the answer and rationale

Answer: D

Transfusion for stable hospitalized adults follows a restrictive threshold of about 7 g/dL, with 8 g/dL an accepted threshold after orthopedic surgery or with preexisting cardiovascular disease (AABB 2023). The client with coronary artery disease after hip repair is below 8 g/dL and now has symptoms, so transfusion is expected. The client with pneumonia has the lowest number, but a stable client without heart disease at 7.3 g/dL is still above the 7 g/dL threshold. The client with kidney disease at 8.8 g/dL is managed with the erythropoiesis-stimulating agent, and the stable client with iron deficiency needs iron replacement, not blood.

📚 Learn it: The CBC: Hemoglobin, White Cells and Platelets

Question 13 of 20

A client with type 2 diabetes has a hemoglobin A1c of 9.2% and says, 'That can't be right. My morning fingerstick readings are usually 110 to 130.' Which response by the nurse is accurate?

  1. 'The A1c shows your average glucose over about 3 months, including after meals.'
  2. 'The A1c mostly reflects your glucose levels over the past week or two.'
  3. 'With fasting readings like yours, the A1c should be closer to 6% than 9.2%.'
  4. 'Morning readings are the best guide, so we should repeat the A1c to check it.'
Show the answer and rationale

Answer: A

Hemoglobin A1c measures glucose bound to hemoglobin over the life of the red blood cell, so it reflects average glucose over the past 2 to 3 months, including after-meal and overnight highs that fasting checks miss; 9.2% corresponds to an average glucose of about 217 mg/dL. Expecting an A1c near 6% from good fasting readings is the common mistake, because fasting values leave out the rest of the day; the usual goal for most adults is below 7%. The A1c does not mostly reflect the last week or two, and repeating it because morning readings look good would delay a needed change in treatment.

📚 Learn it: BUN, Creatinine, Glucose and the Kidney Ratio

Question 14 of 20 · Select all that apply

A nurse is collecting blood for a PT/INR and aPTT from a client who has a continuous heparin infusion running in the left forearm. A light-blue-top (sodium citrate) tube and a butterfly needle will be used. Which actions should the nurse take? Select all that apply.

  1. Gently invert the filled tube about 4 times
  2. Shake the tube firmly to mix the blood with the anticoagulant
  3. Fill a lavender-top (EDTA) tube before the light-blue-top tube
  4. Fill a discard tube first, then fill the light-blue-top tube
  5. Fill the light-blue-top tube to the fill line marked on the tube
  6. Draw the sample from a vein in the right arm
Show the answer and rationale

Answer: A, D, E, F

Blood drawn near a heparin infusion is contaminated with heparin and gives a falsely prolonged aPTT, so the sample comes from the other arm. With a butterfly, the air in the tubing would underfill the citrate tube, so a discard tube is drawn first, and the tube is filled to its line to keep the 9-to-1 ratio of blood to citrate, then gently inverted about 4 times to mix. Shaking can hemolyze or activate the sample, and filling an EDTA tube first can carry its additive into the citrate tube, so the light-blue tube comes before serum, heparin and EDTA tubes.

📚 Learn it: Therapeutic Drug Levels and the Clotting Tests

Question 15 of 20

A 61-year-old client comes to the emergency department with fatigue and shortness of breath on exertion. The client says, 'Four days ago I had crushing chest pressure for about 3 hours, but it went away, so I didn't come in.' The client has no pain now. Laboratory results: troponin I well above the upper reference limit, CK-MB within normal limits. Which interpretation is most accurate?

  1. The results fit a myocardial infarction a few days ago, since troponin stays elevated longer than CK-MB
  2. The normal CK-MB means the chest pressure was stable angina rather than an infarction
  3. The normal CK-MB shows the heart muscle was not damaged, so the high troponin is most likely a false-positive result
  4. The infarction is still evolving, and the CK-MB will rise over the next few hours
Show the answer and rationale

Answer: A

Troponin rises within hours of heart muscle injury and stays elevated for about 5 to 14 days, while CK-MB usually returns to normal within about 2 days, so a high troponin with a normal CK-MB fits an infarction several days ago, which matches 3 hours of chest pressure 4 days ago. The nurse reports it and anticipates an ECG, serial troponins and a cardiac workup. Expecting the CK-MB to rise soon is the runner-up, but that applies to an infarction that has just begun, not pain that ended 4 days ago. A normal CK-MB does not make the troponin a false-positive, and stable angina does not raise troponin.

📚 Learn it: Troponin, BNP, Liver Enzymes and Lactate

Question 16 of 20

A 72-year-old client is on day 5 of IV vancomycin every 12 hours for a methicillin-resistant Staphylococcus aureus bloodstream infection. The trough level drawn this morning is within the target range set by the pharmacist. Before hanging the next dose, which finding should the nurse report to the provider?

  1. White blood cell count 10,900/mm³, down from 18,600/mm³ on admission
  2. Temperature 99.3°F (37.4°C), down from 102.4°F (39.1°C) on admission
  3. Neck flushing during yesterday's infusion that faded when the rate was slowed
  4. Creatinine 1.5 mg/dL, up from 0.8 mg/dL 2 days ago, with urine output of 25 mL/hr
Show the answer and rationale

Answer: D

A creatinine that nearly doubles within 2 days with falling urine output is acute kidney injury, the most important adverse effect of vancomycin, and it can develop even when the trough is in range, so the nurse reports it before the dose so the provider and pharmacist can change the dose or the drug. Infusion-related flushing is the runner-up because it is a true vancomycin reaction, but it is managed by infusing more slowly and had already resolved. A falling temperature and white blood cell count show that the infection is responding.

📚 Learn it: Therapeutic Drug Levels and the Clotting Tests

Question 17 of 20

A 72-year-old client is admitted after lying on the floor at home for about 18 hours following a fall. The urine is dark brown. Urinalysis shows a dipstick result of large blood, 0 to 2 red blood cells per high-power field, and a specific gravity of 1.028. Creatine kinase is 38,000 units/L. Which prescription should the nurse anticipate?

  1. A urology consult and cystoscopy today to find the source of the urinary bleeding
  2. A fluid restriction of 1,500 mL/day and daily weights to protect the kidneys
  3. An oral antibiotic for a urinary tract infection after a urine culture is sent
  4. IV 0.9% sodium chloride to keep the urine output about 200 to 300 mL/hr
Show the answer and rationale

Answer: D

A dipstick strongly positive for blood with almost no red cells on microscopy means the pigment is myoglobin, not blood, and a creatine kinase of 38,000 units/L after a long lie confirms rhabdomyolysis. Myoglobin injures the kidney tubules, so aggressive IV isotonic fluid that keeps the urine output around 200 to 300 mL/hr is the main treatment, with close monitoring of potassium released from damaged muscle. Cystoscopy is the runner-up because the dipstick reads 'blood', but bleeding in the urinary tract would show red cells under the microscope. Restricting fluid to 1,500 mL/day would worsen the kidney injury, and nothing in the findings points to infection, so an antibiotic is not anticipated.

📚 Learn it: Urinalysis, Specific Gravity and Collecting It Right

Question 18 of 20

A client receiving outpatient chemotherapy for breast cancer has an absolute neutrophil count of 600/mm³ on day 10 of the cycle. The nurse reviews home precautions. Which statement by the client indicates that the teaching was effective?

  1. 'I'll call right away for a temperature of 100.4°F (38°C), even if I feel fine.'
  2. 'If I get a fever, I'll take acetaminophen first and call if it is still high in 4 hours.'
  3. 'I'll check my temperature rectally, because that reading is the most accurate one.'
  4. 'I'll get the nasal spray flu vaccine this week so that I don't catch the flu.'
Show the answer and rationale

Answer: A

With an ANC below 1,000/mm³, fever may be the only sign of a serious infection, because too few neutrophils are present to produce pus, redness or swelling. A temperature of 100.4°F (38°C) or higher is the level clients are taught to report, and neutropenic fever needs cultures and IV antibiotics within about an hour, so calling at once is correct. Taking acetaminophen first is the tempting plan, but it can hide the fever and delays treatment of an infection that can progress to sepsis within hours. Rectal thermometers can injure the mucosa and introduce bacteria, and the live nasal spray flu vaccine is avoided in immunocompromised clients; the inactivated injection is used instead.

📚 Learn it: The CBC: Hemoglobin, White Cells and Platelets

Question 19 of 20

A client who performs peritoneal dialysis at home calls the clinic to describe several findings. Which finding should the nurse recognize as the most concerning?

  1. Fibrin strands in an otherwise clear outflow
  2. Slow outflow after three days without a bowel movement
  3. Mild redness at the catheter exit site with no drainage
  4. Cloudy outflow with abdominal tenderness
Show the answer and rationale

Answer: D

Cloudy dialysate outflow is often the first sign of peritonitis, the most serious complication of peritoneal dialysis, and abdominal tenderness strengthens the suspicion; the client needs prompt evaluation, a culture of the fluid, and antibiotics. Mild redness at the exit site without drainage is worth reporting, which makes it tempting, but it is a local skin finding and less dangerous than infection inside the peritoneum. Constipation is a common cause of slow outflow and usually improves with a bowel regimen, and fibrin strands in clear fluid are common and are often managed by adding heparin to the dialysate as prescribed.

📚 Learn it: BUN, Creatinine, Glucose and the Kidney Ratio

Question 20 of 20

A client is brought to the emergency department 4 hours after taking an overdose of acetaminophen. The client is alert, has mild nausea, and has normal AST and ALT results. The spouse asks, 'His liver tests are normal, so he's going to be fine, right?' Which response by the nurse is accurate?

  1. 'If his liver is hurt, his skin will turn yellow in a few hours.'
  2. 'It is too late for the antidote, so we will watch his liver closely.'
  3. 'Because he is alert and talking, the dose was not dangerous.'
  4. 'Liver injury often does not show in blood tests for a day or more.'
Show the answer and rationale

Answer: D

After an acetaminophen overdose the client may feel only mildly ill for the first day, while the liver enzymes begin rising after about 24 hours and peak around 72 to 96 hours, so normal results at 4 hours do not rule out serious injury. Saying it is too late for the antidote sounds cautious, but treatment depends on the acetaminophen level drawn 4 hours after ingestion and plotted on a nomogram, and acetylcysteine works best when started within 8 hours. Being alert does not show the dose was safe, and jaundice appears days later, not within hours; reassurance based on early findings could delay the antidote.

📚 Learn it: Troponin, BNP, Liver Enzymes and Lactate

Practice 10 more Lab values questions free →

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