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Reduction of Risk Potential

NCLEX Lab Values Practice Questions

Quick answer

Lab value questions hand you a number and ask what it means for the client in front of you, or what you do about it. They live mostly in Reduction of Risk Potential (9 to 15 percent of the exam), and you can expect several on every test because labs show up inside questions from almost every other category too.

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There is no way around it: you need a short list of normal ranges in your head before test day. The exam will not print the reference range next to the value, and a question that gives you a creatinine of 2.4 is useless to you if you cannot tell whether that is normal or not. But memorizing numbers is only half of it. The trap that catches most students is treating a lab value as a stand-alone fact instead of asking what it means for this client. A high hematocrit can mean too many red cells or too little plasma. A normal troponin an hour after chest pain started means very little. A lithium level that is "in range" can still be a problem if the client has been vomiting since morning. Read the number, then read the scenario, then decide.

Practice questions

1

A nurse reviews the morning labs of a 74 year old client admitted with 3 days of vomiting and poor oral intake. Hemoglobin is 17.8 g/dL and hematocrit is 53 percent. The client's hemoglobin on a clinic visit last month was 14.1 g/dL. How should the nurse interpret these results?

  1. AThe client has developed polycythemia and needs a hematology referral
  2. BThe values reflect hemoconcentration from fluid volume deficit
  3. CThe values are within normal limits for an older adult
  4. DThe client has been receiving too many red blood cell transfusions
Show answer

Answer: B

Normal hemoglobin is about 12 to 16 g/dL for women and 14 to 18 g/dL for men, and normal hematocrit is about 37 to 47 percent for women and 42 to 52 percent for men. A sudden rise from a known baseline in a client who is losing fluid points to less plasma, not more red cells. The red cells are the same; the water they sit in has dropped. Expect the values to fall back toward baseline once the client is rehydrated.

Why the others are wrong

Polycythemia (A) is a slow, chronic rise and would not jump this much in a month with a clear dehydration story. The hematocrit is above the normal range, not within it, and age does not raise the upper limit (C). Nothing in the scenario mentions transfusions, and a transfusion history would not be the first explanation when the client is clearly volume depleted (D).

2

A client admitted with pneumonia has a white blood cell count of 18,500/mm3 with 14 percent bands on the differential. The nurse understands that this result indicates which of the following?

  1. AThe bone marrow is releasing immature neutrophils in response to acute bacterial infection
  2. BThe client is immunosuppressed and should be placed in protective isolation
  3. CThe client has a viral infection and antibiotics are not indicated
  4. DThe result is a lab error and the sample should be redrawn
Show answer

Answer: A

A normal WBC is about 5,000 to 10,000/mm3, and bands (immature neutrophils) normally make up less than 5 percent of the differential. A high total count with a high band percentage is called a left shift. It means the marrow cannot keep up with demand for mature neutrophils and is sending out young ones early, which is the classic picture of an acute bacterial infection.

Why the others are wrong

Immunosuppression (B) shows up as a low WBC, usually under 4,000, not a high one. Viral infections (C) tend to raise lymphocytes, not neutrophils and bands. A left shift in a client who already has pneumonia fits the clinical picture and is not a reason to suspect lab error (D).

3

A client receiving chemotherapy has a platelet count of 38,000/mm3 this morning. Which action should the nurse take first?

  1. APlace the client on bleeding precautions and check the skin and mucous membranes for petechiae and bruising
  2. BEncourage the client to ambulate in the hall three times a day to prevent clots
  3. CAdminister the scheduled subcutaneous enoxaparin as ordered
  4. DAsk the client to use a firm toothbrush and floss daily to prevent gum infection
Show answer

Answer: A

Normal platelets are 150,000 to 400,000/mm3. Below 50,000 the client is at real risk of bleeding from minor trauma, and below 20,000 spontaneous bleeding can occur. Bleeding precautions come first: soft toothbrush, electric razor, no rectal temperatures or suppositories, no IM injections, pressure on puncture sites for 5 minutes, and a skin check for petechiae, purpura and bruising. The nurse should also hold any anticoagulant and notify the provider.

Why the others are wrong

Unsupervised walking in the hall (B) raises fall and bleeding risk, and clot prevention is not the concern at this count. Enoxaparin (C) is an anticoagulant and must be held and the provider called. A firm toothbrush and flossing (D) can cause gum bleeding; the client needs a soft brush and should skip flossing until the count recovers.

4

A nurse is reviewing labs for a client with hypertension who takes an NSAID daily for arthritis. BUN is 32 mg/dL and creatinine is 2.1 mg/dL. Which interpretation is correct?

  1. AThe elevated BUN is more concerning than the creatinine because BUN is specific to the kidney
  2. BThe creatinine is the more reliable marker of kidney function, and this value suggests impaired glomerular filtration
  3. CBoth values are normal for a client with hypertension
  4. DThe BUN is high because of the NSAID, but the creatinine is unrelated to kidney function
Show answer

Answer: B

Normal BUN is about 10 to 20 mg/dL, and normal creatinine is about 0.6 to 1.2 mg/dL. Creatinine is the better marker because it comes from steady muscle breakdown and is cleared almost entirely by the kidney, so it rises mainly when filtration drops. A creatinine of 2.1 is nearly double the upper limit and points to kidney injury, and long term NSAID use with hypertension is a common cause. The nurse should report the result and expect the NSAID to be stopped.

Why the others are wrong

BUN (A) rises with dehydration, high protein intake, GI bleeding and steroids as well as kidney disease, so it is less specific, not more. Neither value is within normal limits, and hypertension does not change the reference range (C). Creatinine is the marker most closely tied to kidney function, so option D has it backwards.

5

A client with type 2 diabetes attends a follow up visit. The hemoglobin A1c result is 8.6 percent. The client says, "My fasting sugar was 118 this morning, so I am doing fine." Which response by the nurse is best?

  1. A"A single fasting reading does not reflect your average control. An A1c of 8.6 means your blood sugar has averaged well above target over the last 2 to 3 months."
  2. B"Your A1c is in the normal range, so keep doing what you are doing."
  3. C"The A1c only measures how your sugar has been for the past week, so this morning's reading matters more."
  4. D"An A1c under 10 percent is the goal for most people with diabetes, so you are close."
Show answer

Answer: A

A1c reflects the percentage of hemoglobin with glucose attached and gives an average of blood glucose over roughly the past 2 to 3 months, the lifespan of a red blood cell. The usual target for most adults with diabetes is below 7 percent, and a nondiabetic range is under 5.7 percent. An 8.6 means average glucose has been close to 200 mg/dL, no matter what one fasting fingerstick says. This is a teaching moment, and the nurse should explain why the two numbers tell different stories.

Why the others are wrong

8.6 percent is well above both the normal range and the treatment target (B). A1c covers months, not a week (C). The goal for most clients is under 7 percent, not under 10 (D).

6

A client arrives in the emergency department with chest pressure that started 45 minutes ago. The initial troponin I is 0.01 ng/mL (within normal limits) and the ECG shows nonspecific changes. The client asks whether this means it was not a heart attack. Which response is accurate?

  1. A"A normal troponin rules out a heart attack, so you will likely be discharged soon."
  2. B"Troponin can take a few hours after the start of symptoms to rise, so we will repeat it and keep monitoring you."
  3. C"Troponin only rises in people who have had a previous heart attack."
  4. D"A normal troponin means the pain is from your lungs, not your heart."
Show answer

Answer: B

Troponin is the most specific cardiac marker, but it begins to rise about 2 to 4 hours after myocardial injury, peaks around 12 to 24 hours, and can stay elevated for 1 to 2 weeks. A normal value drawn under an hour into symptoms is too early to mean anything. Standard practice is a serial draw (often at 3 to 6 hours, sooner with high sensitivity assays) with continuous ECG monitoring in between.

Why the others are wrong

One early normal troponin never rules out an MI (A). Troponin rises with any myocardial injury, not only repeat events (C). A normal troponin does not identify the cause of the pain, and lung problems are not diagnosed by elimination from a single cardiac lab (D).

7

A client with a history of heart failure comes to the clinic with a 4 pound weight gain in 3 days and new ankle swelling. The B type natriuretic peptide (BNP) result is 920 pg/mL. The nurse recognizes that this result indicates which of the following?

  1. AThe client's heart failure is well controlled and no change is needed
  2. BThe ventricles are stretched from volume overload and the heart failure is worsening
  3. CThe client has an acute myocardial infarction and needs a cardiac catheterization
  4. DThe result is unrelated to the weight gain and most likely reflects a kidney problem
Show answer

Answer: B

BNP is released by the ventricles when they are stretched by extra volume. A normal BNP is under 100 pg/mL. Values above 400 strongly suggest heart failure, and the higher the number, the worse the ventricular strain. A BNP of 920 together with rapid weight gain and new edema is a clear picture of decompensation. The nurse should assess lung sounds, oxygen saturation and the client's diuretic use, and report the findings for a likely medication adjustment.

Why the others are wrong

A BNP this high is not compatible with well controlled heart failure (A). BNP is a marker of ventricular stretch, not infarction; troponin is the marker for MI (C). Kidney disease can raise BNP somewhat, but the weight gain and edema make heart failure the obvious explanation, and the result fits it (D).

8

A client admitted with acetaminophen overdose has an ALT of 1,850 units/L and an AST of 1,420 units/L 36 hours after ingestion. Which action by the nurse is the priority?

  1. AEncourage the client to increase oral intake of high protein foods
  2. BMonitor for signs of hepatic injury such as right upper quadrant pain, jaundice and bleeding, and ensure the N acetylcysteine infusion continues on schedule
  3. CHold the N acetylcysteine until the enzyme levels come down
  4. DPrepare the client for immediate discharge because the enzymes will normalize on their own
Show answer

Answer: B

ALT (normal about 7 to 56 units/L) and AST (normal about 10 to 40 units/L) are enzymes released from damaged liver cells. ALT is more liver specific; AST is also found in heart and muscle. Levels in the thousands indicate acute hepatocellular injury. In acetaminophen toxicity the enzymes typically peak around 48 to 72 hours, so this client is still in the window where damage can progress. The antidote, N acetylcysteine, must be given on schedule, and the nurse watches for jaundice, confusion, bleeding and worsening coagulation studies.

Why the others are wrong

Pushing dietary protein (A) is not the priority during acute liver injury and may worsen encephalopathy risk. The antidote is most useful during the injury phase and is never held because enzymes are high; that is exactly when it is needed (C). Enzymes this high with a known toxic ingestion require close monitoring, not discharge (D).

9

A client with bipolar disorder who takes lithium carbonate calls the clinic to report 2 days of diarrhea and feeling "shaky and off balance." The most recent lithium level, drawn last week, was 1.1 mEq/L. Which instruction should the nurse give first?

  1. A"Your level was in the normal range last week, so keep taking your usual dose."
  2. B"Skip your next lithium dose and come in today for a lithium level and assessment."
  3. C"Double your fluid intake and take an extra dose to make up for what you lost in the diarrhea."
  4. D"Stop drinking fluids until the diarrhea resolves so you do not dilute the medication."
Show answer

Answer: B

The therapeutic range for lithium is narrow, 0.6 to 1.2 mEq/L, and toxicity can start just above it. Diarrhea, vomiting and dehydration raise the level because lithium is handled by the kidney the same way sodium is: when the body holds on to sodium and water, it holds on to lithium too. A level of 1.1 last week was fine, but 2 days of fluid loss plus new coarse tremor and unsteady gait are early toxicity signs. The client needs to hold the dose and be seen today for a level, renal function and assessment.

Why the others are wrong

A level from last week does not reflect the current situation after fluid loss (A). An extra dose would push the level higher (C). Restricting fluids concentrates lithium further; the client needs steady fluid and sodium intake, not less (D).

10

A nurse reviews a urinalysis for a client admitted with weakness and poor oral intake. Results show specific gravity 1.032, color dark amber, glucose negative, protein negative, nitrites negative, leukocyte esterase negative. Which interpretation is correct?

  1. AThe urine is concentrated, consistent with dehydration
  2. BThe urine is dilute, consistent with fluid overload or diabetes insipidus
  3. CThe result indicates a urinary tract infection
  4. DThe result indicates uncontrolled diabetes mellitus
Show answer

Answer: A

Normal urine specific gravity is about 1.005 to 1.030. A value at or above the upper end with dark amber color means the kidneys are concentrating urine to conserve water, which is exactly what they should do in a client who is not drinking enough. The nurse would expect the specific gravity to fall as the client is rehydrated.

Why the others are wrong

Dilute urine (B) would show a low specific gravity, around 1.005 or below, and pale color. A UTI (C) would typically show positive nitrites, positive leukocyte esterase, and often cloudiness; all of those are negative here. Uncontrolled diabetes (D) would show glucose in the urine, which is negative.

Quick tips

  • Learn the ranges in groups, not as a random list. Put kidney labs together (BUN, creatinine), liver labs together (ALT, AST, bilirubin), cardiac labs together (troponin, BNP) and blood counts together (hemoglobin, hematocrit, WBC, platelets). You will remember them faster and the question will usually give you labs in the same groups.
  • When hemoglobin and hematocrit move together, decide whether the client lost red cells or lost water. The scenario will tell you: bleeding and chronic disease drop both, dehydration raises both, and the fix is completely different.
  • Timing matters for cardiac markers. A single early troponin is a starting point, not an answer. BNP, on the other hand, reflects the current volume state and tracks with weight gain and edema.
  • For narrow range drugs like lithium, the level is only half the story. Ask what has changed in the client: vomiting, diarrhea, a new diuretic, a low sodium diet, or a hot day with heavy sweating can all push a safe level into toxic territory.
  • When a lab value is far outside normal, the test writers are usually looking for one of three responses: start precautions, hold a medication, or notify the provider. Pick the option that protects the client right now, then think about the longer term fix.

Related topics

FAQ

Which lab values do I actually need to memorize for the NCLEX?

Start with the ones that drive nursing action: hemoglobin, hematocrit, WBC, platelets, BUN, creatinine, A1c, troponin, BNP, ALT and AST, plus the narrow range drug levels like lithium and digoxin. Add the electrolytes and coagulation studies, which have their own pages. If a value changes what you would do at the bedside, it is worth knowing.

Does the NCLEX give you the normal range in the question?

Usually not. Some questions include a reference range in a lab table, especially in the Next Generation case study format, but many do not. Assume you will have to supply the range yourself and know the ones above cold.

Why is creatinine a better kidney test than BUN?

Creatinine comes from a steady process (muscle metabolism) and is cleared almost entirely by the kidneys, so it rises mainly when filtration falls. BUN also rises with dehydration, a high protein diet, GI bleeding and steroid use, so a high BUN by itself cannot tell you whether the kidney is the problem. When both are up but creatinine is proportionally higher, think kidney injury; when BUN is up out of proportion, think dehydration or bleeding.

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