Laboratory values and diagnostic tests

60 NCLEX-RN practice questions on Laboratory values and diagnostic tests, part of Reduction of Risk Potential. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Medium · Select all that apply

   The nurse is drawing blood for a serum potassium level. Which practices can produce a falsely high result?

   1. AHaving the client pump the fist repeatedly
   2. BDrawing from the arm with D5W infusing
   3. CLeaving the tourniquet on for several minutes
   4. DDrawing from the arm with potassium chloride infusing
   5. EGently inverting the tube as directed
   6. FForcing the blood through a small needle into the tube

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   Answer: A, C, D, F

   Analyse cues: a falsely high potassium (pseudohyperkalaemia) comes from potassium leaving cells or entering the sample. A long tourniquet time, fist pumping and haemolysis from forcing blood through a small needle release cellular potassium, and drawing above a potassium infusion contaminates the sample. A D5W line dilutes the sample instead, and gentle inversion is correct technique. Redraw from the other arm when the result does not fit the client.

   • B: Dextrose in water dilutes the sample and tends to lower potassium.
   • E: Gentle inversion mixes additive without haemolysis.

2. Question 2 · Medium · Matrix

   A client is in the endoscopy recovery area after a colonoscopy with polyp removal under moderate sedation. For each colonoscopy finding, indicate whether it is expected or requires follow-up.

   For each row, choose: Expected / Requires follow-up

   1. Rigid abdomen with temperature 101.6°F (38.7°C)
   2. Drowsy but easily roused
   3. Abdominal cramping and passing gas
   4. BP 88/52 mm Hg with heart rate 118/min
   5. Passing several large clots of bright red blood
   6. A streak of blood on the first stool

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   Answer:

   • Rigid abdomen with temperature 101.6°F (38.7°C): Requires follow-up
   • Drowsy but easily roused: Expected
   • Abdominal cramping and passing gas: Expected
   • BP 88/52 mm Hg with heart rate 118/min: Requires follow-up
   • Passing several large clots of bright red blood: Requires follow-up
   • A streak of blood on the first stool: Expected

   Recognise cues: cramping and gas from insufflated air, drowsiness after sedation and a streak of blood after polypectomy are expected. A rigid abdomen with fever suggests perforation, large clots point to post-polypectomy bleeding, and hypotension with tachycardia suggests haemorrhage or perforation.

   • Rigid abdomen with temperature 101.6°F (38.7°C): Suggests bowel perforation.
   • Drowsy but easily roused: An expected effect of moderate sedation.
   • Abdominal cramping and passing gas: Air is used to inflate the colon.
   • BP 88/52 mm Hg with heart rate 118/min: Shock from bleeding or perforation.
   • Passing several large clots of bright red blood: Signals post-polypectomy haemorrhage.
   • A streak of blood on the first stool: Minor oozing is expected after polypectomy.

3. Question 3 · Medium · Select all that apply

   A client returns from a cardiac catheterisation done through the right radial artery, with a compression band on the wrist. Which actions should the nurse include in the care?

   1. AKeep the client flat in bed for 6 hours
   2. BCheck the radial pulse, hand colour and capillary refill often
   3. CKeep the wrist straight and avoid flexing it
   4. DRelease air from the band gradually as the protocol directs
   5. EReport numbness, tingling or a cold, pale hand
   6. FTake blood pressure only on the other arm

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   Answer: B, C, D, E, F

   Generate solutions: radial access lets the client sit up and walk early, but the hand must be protected. Check the radial pulse, colour and capillary refill often, keep the wrist straight, take no blood pressure in that arm, release the band gradually by protocol, and report numbness or a cold, pale hand. Prolonged flat bed rest is needed after femoral access, not radial.

   • A: Flat bed rest applies to femoral access; radial clients sit up early.

4. Question 4 · Hard · Matrix

   An older client admitted from a care home is lethargic, with a serum sodium of 159 mEq/L (reference 135-145 mEq/L). For each action, indicate whether it is indicated or contraindicated.

   For each row, choose: Indicated / Contraindicated

   1. Infuse D5W rapidly to normalise sodium within 6 hours
   2. Check serum sodium as often as prescribed
   3. Offer sips of water often if swallowing is safe
   4. Give 3% sodium chloride
   5. Institute seizure precautions
   6. Give the prescribed hypotonic IV fluid at the set rate

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   Answer:

   • Infuse D5W rapidly to normalise sodium within 6 hours: Contraindicated
   • Check serum sodium as often as prescribed: Indicated
   • Offer sips of water often if swallowing is safe: Indicated
   • Give 3% sodium chloride: Contraindicated
   • Institute seizure precautions: Indicated
   • Give the prescribed hypotonic IV fluid at the set rate: Indicated

   Generate solutions: chronic hypernatraemia must be corrected slowly, by no more than about 10-12 mEq/L in 24 hours, because brain cells have adapted and rapid correction causes cerebral oedema and seizures. Hypotonic fluids as prescribed, regular sodium checks, neurological checks, seizure precautions and safe oral water are indicated. Hypertonic saline would raise the sodium further.

   • Infuse D5W rapidly to normalise sodium within 6 hours: Rapid correction causes cerebral oedema.
   • Check serum sodium as often as prescribed: Detects a fall that is too fast.
   • Offer sips of water often if swallowing is safe: Free water corrects the deficit.
   • Give 3% sodium chloride: Hypertonic saline worsens hypernatraemia.
   • Institute seizure precautions: Both the imbalance and its correction can cause seizures.
   • Give the prescribed hypotonic IV fluid at the set rate: Replaces free water gradually.

5. Question 5 · Medium · Select all that apply

   A client with SIADH on a fluid restriction has a serum sodium of 126 mEq/L (reference 135-145 mEq/L). Which findings require follow-up?

   1. AMucous membranes moist
   2. BStates, "I have a pounding headache."
   3. CWeight 0.2 kg higher than yesterday
   4. DReports feeling thirsty on the restriction
   5. EUrine specific gravity 1.030
   6. FIs disoriented to time for the first time

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   Answer: B, F

   Recognise cues: in hyponatraemia, water shifts into brain cells, so new neurological signs are the dangerous cues. A new headache and new disorientation suggest cerebral oedema and can progress to seizures. A concentrated urine, thirst on the restriction and moist mucous membranes are expected with SIADH and its treatment, and a 0.2 kg weight change is trivial.

   • A: This is a normal finding.
   • C: This small change is within daily variation.
   • D: Thirst is an expected effect of fluid restriction.
   • E: Concentrated urine is expected in SIADH.

6. Question 6 · Hard · Matrix

   Using pH 7.35-7.45, PaCO2 35-45 mm Hg and HCO3- 22-26 mEq/L, indicate the compensation status of each arterial blood gas.

   For each row, choose: Uncompensated / Partially compensated / Fully compensated

   1. pH 7.33, PaCO2 60 mm Hg, HCO3- 30 mEq/L
   2. pH 7.47, PaCO2 48 mm Hg, HCO3- 34 mEq/L
   3. pH 7.52, PaCO2 41 mm Hg, HCO3- 33 mEq/L
   4. pH 7.29, PaCO2 58 mm Hg, HCO3- 25 mEq/L
   5. pH 7.37, PaCO2 30 mm Hg, HCO3- 17 mEq/L

   Answer and explanation in LearnFree account

7. Question 7 · Hard · Select all that apply

   During a CT scan, a minute after IV iodinated contrast is injected, the client develops hives, wheezing and a hoarse voice. BP is 84/50 mm Hg. Which actions should the nurse take?

   1. AStop the contrast injection
   2. BCall for the emergency response team
   3. CLay the client flat with the legs raised
   4. DGive IM epinephrine as the protocol directs
   5. EGive oxygen and keep the IV line open
   6. FGive oral diphenhydramine and observe for 30 minutes

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8. Question 8 · Medium · Select all that apply

   A client with diabetes has a fingerstick glucose of 52 mg/dL. The client is awake, sweaty and able to swallow. Which actions should the nurse take?

   1. AOffer a snack or the next meal once the glucose recovers
   2. BGive the scheduled rapid-acting insulin dose
   3. CRecheck the glucose in 15 minutes
   4. DGive glucagon intramuscularly now
   5. EGive 15 g of fast-acting carbohydrate such as 4 oz of juice
   6. FGive a chocolate bar as the first treatment

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9. Question 9 · Hard · Matrix

   The nurse calculates the absolute neutrophil count (ANC) for four clients receiving chemotherapy. For each set of results, indicate whether the ANC is below 500/mm³.

   For each row, choose: Below 500/mm³ / 500/mm³ or above

   1. WBC 900/mm³, neutrophils 50%, bands 0%
   2. WBC 1,800/mm³, neutrophils 20%, bands 4%
   3. WBC 3,000/mm³, neutrophils 30%, bands 5%
   4. WBC 2,500/mm³, neutrophils 18%, bands 3%

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10. Question 10 · Easy · Select all that apply

    The nurse reviews admission results for an adult client. Which values fall within the usual adult reference ranges?

    1. AWBC count 7,500/mm³
    2. BSerum potassium 4.2 mEq/L
    3. CHaemoglobin 9.8 g/dL in an adult woman
    4. DFasting plasma glucose 88 mg/dL
    5. ESerum sodium 140 mEq/L
    6. FPlatelet count 90,000/mm³

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11. Question 11 · Hard · Select all that apply

    The nurse reviews morning results for six clients. Which results should the nurse report to the health care provider immediately?

    1. ADay 1 after hip surgery: haemoglobin 10.4 g/dL, before surgery 12.1
    2. BHeparin infusion for 5 days: platelets 62,000/mm³, baseline 240,000/mm³
    3. CCOPD at baseline: pH 7.37, PaCO2 50 mm Hg, HCO3- 29 mEq/L
    4. DKidney failure on dialysis: creatinine 6.8 mg/dL, last week 6.5
    5. EType 2 diabetes: fasting plasma glucose 142 mg/dL
    6. FChest pain: troponin I 0.6 ng/mL, up from 0.01 (reference under 0.04)

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12. Question 12 · Medium · Matrix

    The nurse compares findings in two clients with hyperglycaemic crises. For each finding, indicate whether it fits diabetic ketoacidosis (DKA) or hyperosmolar hyperglycaemic state (HHS).

    For each row, choose: DKA / HHS

    1. Glucose 980 mg/dL with serum osmolality 365 mOsm/kg
    2. pH 7.18 with bicarbonate 10 mEq/L
    3. pH 7.36 with no serum ketones
    4. Deep, rapid Kussmaul respirations
    5. Raised serum beta-hydroxybutyrate

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13. Question 13 · Medium · Select all that apply

    A client is scheduled for a pharmacologic stress test with regadenoson and nuclear imaging. Which statements should the nurse include in the teaching?

    1. AAvoid coffee, tea, cola and chocolate for at least 12 hours before
    2. BDrink a cup of coffee on the way to stay alert
    3. CBrief flushing or chest tightness during the injection is common
    4. DEat a large breakfast to prevent low blood sugar
    5. ETell staff if you have asthma or have been wheezing

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14. Question 14 · Hard · Select all that apply

    A client with a serum potassium of 2.9 mEq/L has a prescription for potassium chloride 40 mEq IV through a peripheral line. Which actions should the nurse take?

    1. AConfirm urine output of at least 30 mL/h before starting
    2. BGive the infusion through an infusion pump
    3. CGive the dose by IV push over 2 minutes
    4. DCheck the serum magnesium level
    5. ERun it no faster than 10 mEq/h through the peripheral line
    6. FCheck the IV site often for pain and infiltration

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15. Question 15 · Medium · Matrix

    A client with cirrhosis and tense ascites is scheduled for a paracentesis. For each nursing action, indicate whether it is indicated or contraindicated.

    For each row, choose: Indicated / Contraindicated

    1. Position the client upright at the edge of the bed
    2. Position the client flat on the back
    3. Encourage a full bladder to lift the bowel away
    4. Monitor BP and heart rate after large-volume removal
    5. Ask the client to empty the bladder before the procedure
    6. Measure weight and abdominal girth before and after

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16. Question 16 · Medium · Matrix

    The nurse reviews results for a client with stage 4 chronic kidney disease seen in clinic. For each result, indicate whether it is expected for this client or requires follow-up.

    For each row, choose: Expected / Requires follow-up

    1. Phosphorus 5.1 mg/dL (reference 2.5-4.5)
    2. Bicarbonate 13 mEq/L (reference 22-29) with deep, rapid breathing
    3. Potassium 6.6 mEq/L (reference 3.5-5.0)
    4. Haemoglobin 10.1 g/dL
    5. Creatinine 3.6 mg/dL, last month 3.5 mg/dL

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17. Question 17 · Hard · Matrix

    A client with acute leukaemia has a platelet count of 22,000/mm³ (reference 150,000-400,000/mm³). For each order or action, indicate whether it is indicated or contraindicated.

    For each row, choose: Indicated / Contraindicated

    1. Give a daily stool softener
    2. Give ketorolac IM for pain
    3. Shave with an electric razor
    4. Give an enema for constipation
    5. Brush teeth with a soft-bristled toothbrush
    6. Measure temperature rectally

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18. Question 18 · Medium · Select all that apply

    A client has returned to the unit after a bronchoscopy with transbronchial biopsy done under moderate sedation and topical throat anaesthetic. Which actions should the nurse take?

    1. ACheck for a gag reflex before offering any fluids
    2. BMonitor for stridor and a fall in SpO2
    3. CReport bright red blood that is more than streaks in the sputum
    4. DKeep the client lying flat for 6 hours
    5. EGive a warm saline gargle for throat comfort right away
    6. FOffer warm fluids as soon as the client is awake

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19. Question 19 · Easy · Select all that apply

    A client is scheduled for a fasting plasma glucose test tomorrow morning. Which instructions should the nurse give?

    1. APlain water may be taken during the fasting period
    2. BTake nothing by mouth except water for at least 8 hours before the test
    3. CChewing sugared gum in the morning is acceptable
    4. DA cup of sweetened coffee will not affect the result
    5. EEat a high-carbohydrate meal just before coming in

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20. Question 20 · Medium · Matrix

    The nurse is planning care for a client after a percutaneous kidney biopsy. For each action, indicate whether it is indicated or contraindicated.

    For each row, choose: Indicated / Contraindicated

    1. Give ibuprofen for biopsy-site pain
    2. Allow weightlifting at the gym the next day
    3. Encourage oral fluids unless restricted
    4. Check vital signs often for the first hours
    5. Inspect each urine sample for blood
    6. Keep the client on bed rest for the prescribed hours

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21. Question 21 · Medium · Select all that apply

    The nurse is collecting a radial arterial blood gas sample. Which actions are appropriate?

    1. AHold firm pressure on the site for at least 5 minutes
    2. BShake the syringe vigorously to mix the heparin
    3. CExpel any air bubbles from the syringe
    4. DDraw the sample within 5 minutes after suctioning
    5. EConfirm collateral circulation with an Allen test first
    6. FRecord the client's oxygen therapy on the request

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22. Question 22 · Hard · Select all that apply

    A client with gallstones in the common bile duct had an ERCP with sphincterotomy under sedation this morning. Which post-procedure findings require follow-up?

    1. AMild sore throat
    2. BSevere epigastric pain that radiates to the back
    3. CGag reflex present and tolerating sips
    4. DTemperature 102.2°F (39°C) with chills
    5. EMild bloating and belching
    6. FSerum lipase three times the upper limit of normal

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23. Question 23 · Medium · Select all that apply

    A client is scheduled for an MRI of the brain with IV gadolinium contrast. Which information should the nurse obtain and report before the scan?

    1. ACompletion of a bowel preparation
    2. BA history of metal grinding or welding work
    3. CA recent eGFR in a client with kidney disease
    4. DAny medication patch with a foil backing
    5. EWhether the client is allergic to shellfish
    6. FWhether the client has a pacemaker or implanted defibrillator

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24. Question 24 · Hard · Matrix

    Using pH 7.35-7.45, PaCO2 35-45 mm Hg and HCO3- 22-26 mEq/L, indicate the primary acid-base disorder for each client.

    For each row, choose: Respiratory acidosis / Metabolic acidosis / Metabolic alkalosis

    1. Persistent vomiting: pH 7.50, PaCO2 46, HCO3- 35
    2. Four days of profuse diarrhoea: pH 7.30, PaCO2 33, HCO3- 16
    3. Tiring asthma attack: pH 7.28, PaCO2 52, HCO3- 24
    4. Opioid PCA, RR 8/min: pH 7.30, PaCO2 55, HCO3- 25
    5. Septic shock, lactate 5 mmol/L: pH 7.29, PaCO2 30, HCO3- 14

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25. Question 25 · Medium

    Two hours after a femoral cardiac catheterization, the client says, "My groin feels warm and wet." What is the nurse's first action?

    1. ARaise the head of the bed to a sitting position
    2. BNotify the health care provider of the client's report
    3. CRecheck the site in 15 minutes during routine vital signs
    4. DApply firm pressure just above the puncture site

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