20 Lab Testing & EKG Practice Questions & Answers

Every Lab Testing & EKG practice question from the CCMA Practice Test (NHA Clinical Medical Assistant), with the correct answer and a short explanation.

Start practice test →

1. A patient suspects early pregnancy, and the provider orders a urine hCG test. Which specimen instruction gives the most reliable result?
- A.Collect a random urine late in the day
- B.Bring a first-morning urine specimen✓ Answer
- C.Collect urine two hours after a meal
- D.Collect urine after drinking extra water
The first-morning void is the most concentrated urine of the day, so it contains the highest hCG concentration. Dilute specimens, such as those collected after extra fluids or late in the day, can give a false-negative result in early pregnancy.
Ref QB-X6W282Source: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: nonblood specimen collection (urine hCG)Report a problem with this question
2. A patient begins a 24-hour urine collection at 7:00 a.m. Monday. What should the medical assistant tell the patient about the first void and the end of the collection?
- A.Save the 7 a.m. void, then stop collecting before 7 a.m. Tuesday
- B.Discard the 7 a.m. void, and stop collecting at bedtime Monday night
- C.Discard the 7 a.m. void, then save all urine through 7 a.m. Tuesday✓ Answer
- D.Save the 7 a.m. void, and also save the 7 a.m. Tuesday void
The first morning void is urine produced before the timed period began, so it is discarded and the start time is noted. Every void for the next 24 hours is saved, including a final void at 7 a.m. Tuesday, and the container is kept refrigerated or on ice. Saving both 7 a.m. voids would add urine from outside the 24-hour window.
Ref QB-DPCJFYSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: 24-hour urine collection techniqueReport a problem with this question
3. During a workplace drug-screen collection, the donor hands the medical assistant the specimen cup. Under chain-of-custody procedure, what should the MA do next?
- A.Pour off a portion for a quick dipstick test
- B.Refrigerate the cup before recording the details
- C.Check the specimen temperature within minutes✓ Answer
- D.Seal the cup after the donor has left the area
Reading the temperature strip within minutes of the void (roughly 90-100 F / 32-38 C) verifies that the specimen is fresh and was not substituted or diluted. The cup is then sealed with tamper-evident tape in the donor's presence, the donor initials the seal, and every transfer is documented on the custody form.
Ref QB-W6JQ2ZSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: chain of custody (drug-screen collection)Report a problem with this question
4. The provider orders a rapid strep test. How should the medical assistant collect the throat specimen?
- A.Swab the tonsils and posterior pharynx, avoiding the tongue✓ Answer
- B.Swab the inside of both cheeks and under the tongue
- C.Have the patient gargle saline and spit into a sterile cup
- D.Swab the front of the tongue where the coating is thickest
Group A streptococcus infects the tonsils and posterior pharynx, so the swab must touch those areas while a tongue depressor holds the tongue down. Touching the tongue, cheeks or teeth contaminates the swab with normal oral flora and saliva and can cause a false-negative result.
Ref QB-CPZ7AXSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: collection of throat cultures / rapid strepReport a problem with this question
5. A patient will collect a sputum specimen for culture at home. Which instruction is correct?
- A.At bedtime, clear the throat lightly into a clean food jar
- B.Rinse with water on waking, then cough deeply into a sterile cup✓ Answer
- C.After breakfast, spit saliva from the mouth into a sterile cup
- D.Rinse with mouthwash on waking, then cough into a sterile cup
Secretions pool in the lungs overnight, so an early-morning specimen gives the best yield. Rinsing with plain water reduces oral contamination, while mouthwash can kill the organisms being cultured. The specimen must come from a deep cough, not saliva, and go into a sterile container.
Ref QB-V67DVXSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: nonblood specimen collection (sputum)Report a problem with this question
6. On a CLIA-waived rapid strep cassette, a line appears at the test (T) position, but no line appears at the control (C) position. How should the medical assistant handle the result?
- A.Weak positive; ask the provider to interpret it
- B.Positive, because the test line is visible
- C.Negative, because the control line is absent
- D.Invalid; repeat the test with a new cassette✓ Answer
The control line is the built-in internal procedural control: it shows that enough specimen was added, the reagents worked and the sample migrated correctly. Without it no result can be trusted, even a visible test line, so the test is invalid and must be repeated with a new device per the manufacturer's instructions.
Ref QB-BPNV4WSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: internal quality control (CLIA-waived testing)Report a problem with this question
7. To save time, a coworker suggests reading every pad of a CLIA-waived urine reagent strip at 30 seconds, even though the bottle chart lists different read times for different pads. Why is this unacceptable?
- A.CLIA rules require reading every reagent pad at exactly 60 seconds
- B.Dipsticks must be read only by a provider, not a medical assistant
- C.Dipstick results may only be reported if confirmed by a reference lab
- D.Changing the manufacturer's procedure means the test is no longer waived✓ Answer
A test keeps its CLIA-waived status only when it is performed exactly as the manufacturer instructs. Each pad's chemical reaction develops over its own time, so reading early or late gives inaccurate results, and any modification turns the test into a non-waived (higher complexity) test the site is not certified to perform.
Ref QB-U6U2QWSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: CLIA-waived regulations (follow manufacturer's instructions)Report a problem with this question
8. A urine specimen is tested correctly and the result is accurate, but the medical assistant enters the result into a different patient's chart. How is this error classified?
- A.An analytical error
- B.A calibration error
- C.A postanalytical error✓ Answer
- D.A preanalytical error
Errors are classified by when they occur. Preanalytical errors happen before testing (patient ID, labeling, preparation, transport), analytical errors happen during testing (reagents, QC, timing, calibration), and postanalytical errors happen after a valid result exists, such as transcription errors, reporting to the wrong chart, or delayed reporting.
Ref QB-APAJXUSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: preanalytical and postanalytical errorsReport a problem with this question
9. A 4-year-old who does not yet know the alphabet needs a distance visual acuity screening. Which approach should the medical assistant use?
- A.A Snellen letter chart read with both eyes open together
- B.A Tumbling E or picture chart at the standard distance✓ Answer
- C.An Ishihara color plate book held at reading distance
- D.A Jaeger near-vision card held about 14 to 16 inches away
Non-readers cannot name letters, so a Tumbling E chart (the child points the direction of the E) or a picture chart measures distance acuity at the standard distance, one eye at a time. Ishihara plates test color vision and a Jaeger card tests near vision, so neither measures distance acuity.
Ref QB-T6GQHVSource: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: vision tests (distance acuity for non-readers)Report a problem with this question
10. During scratch (prick) allergy testing on the forearm, the medical assistant applies histamine and saline at labeled sites along with the allergens. At 15-20 minutes, the histamine site shows no wheal. What does this most likely indicate?
- A.Antihistamine use may be suppressing reactions; notify the provider✓ Answer
- B.The patient has no allergies, so all allergen sites are negative
- C.The saline site should be read as the positive control instead
- D.The sites need to be reread at 48 to 72 hours like a TB test
Histamine is the positive control and should produce a wheal and flare in almost everyone. If it does not, the skin is not reacting, most often because the patient did not stop antihistamines as ordered, so negative allergen results cannot be trusted and the provider must be told. Saline is the negative control, and the 48-72 hour reading belongs to the Mantoux TB test, not allergy scratch testing.
Ref QB-RA7GK3Source: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: allergy testing (scratch test positive and negative controls)Report a problem with this question
11. An asthma patient's personal best peak flow is 500 L/min. In the office she blows 330, 360 and 350 L/min with good technique. What should be recorded, and which zone does it fall in?
- A.360 L/min, yellow zone✓ Answer
- B.347 L/min, yellow zone
- C.330 L/min, red zone
- D.360 L/min, green zone
Peak flow is recorded as the highest of three good efforts, not the average, because the best blow reflects true airway capacity. 360 is 72% of the 500 personal best; the yellow zone is 50-79% (caution, follow the action plan), green is 80-100% and red is below 50%.
Ref QB-8TZAZ2Source: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: peak flow rates (zones based on personal best)Report a problem with this question
12. A patient's first spirometry effort is weak and stops after about 2 seconds, and air can be heard escaping through the nose. What should the medical assistant do?
- A.Record the effort as is, since the first attempt is the most accurate
- B.Apply a nose clip, coach a full hard blast, and repeat for 3 good efforts✓ Answer
- C.Have the patient breathe slowly and steadily into the mouthpiece instead
- D.Average this blow with one more attempt and send that average result
Air leaking through the nose and an early stop both underestimate FVC and FEV1. A nose clip and a tight lip seal prevent leaks, and active coaching gets a maximal inhalation followed by a hard, fast exhalation sustained for about 6 seconds or more. Spirometry requires at least 3 acceptable efforts; it is not a slow breath or a simple average of two blows.
Ref QB-SAJTR4Source: NHA CCMA Test Plan — Domain 3D Point of Care Testing and Laboratory Procedures: spirometry / pulmonary function testingReport a problem with this question
13. During a resting 12-lead EKG, the tracing suddenly shows chaotic, irregular waves with no identifiable P waves, QRS complexes or T waves. What should the medical assistant do first?
- A.Check the patient's responsiveness and pulse✓ Answer
- B.Turn on the 60 Hz filter and rerun the strip
- C.Print the strip and send it to the provider
- D.Re-prep the skin and replace the electrodes
This pattern looks like ventricular fibrillation, a cardiac arrest rhythm. The rule is to assess the patient before assuming artifact: if the patient is unresponsive and pulseless, call for help and start CPR and the AED; only after confirming the patient is stable should the MA troubleshoot electrodes or interference.
Ref QB-9TCN64Source: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: recognize emergent results (dysrhythmia vs artifact)Report a problem with this question
14. A patient is being fitted with a Holter monitor for a 24-hour recording. Which instruction should the medical assistant give?
- A.Shower as usual, since the electrodes are waterproof
- B.Keep a diary of activities and symptoms with their times✓ Answer
- C.Press the button only when you feel symptoms to record
- D.Rest in bed as much as possible during the recording
A Holter records continuously, so the provider matches the timed diary entries against the tracing to link symptoms and activities to rhythm changes. The patient should keep up normal daily activity, keep the electrodes and device dry (no showering or swimming unless the device allows it), and not remove the electrodes. Pressing a button to capture symptoms describes an event monitor.
Ref QB-PAGT8ZSource: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: Holter monitoring patient instructionsReport a problem with this question
15. A patient reports brief palpitations that occur only once or twice a month. The provider wants a tracing captured during an episode. Which device fits this purpose?
- A.A treadmill stress test performed once with BP monitoring
- B.A Holter monitor worn for 24 hours that records continuously
- C.An event monitor worn for weeks that the patient activates✓ Answer
- D.A resting 12-lead EKG repeated at each monthly office visit
An event monitor is worn for weeks (up to about 30 days) and the patient activates it when symptoms occur, so it can catch infrequent episodes and transmit them to the provider. A 24-hour Holter would likely miss a monthly symptom, and an office EKG or a single stress test records only a few minutes.
Ref QB-6TANNYSource: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: ambulatory cardiac monitoring (event monitor vs Holter)Report a problem with this question
16. During a treadmill stress test, the patient becomes pale and sweaty and says he feels dizzy. What should the medical assistant do?
- A.Lower the treadmill speed and continue the test
- B.Record the symptoms and review them after the test
- C.Encourage him to finish the current stage first
- D.Stop the test and notify the provider immediately✓ Answer
Dizziness, pallor and diaphoresis are signs that the heart may not be getting enough blood flow under stress, and they are standard reasons to stop the test, along with chest pain, severe shortness of breath, a significant BP change or a dangerous arrhythmia. Continuing, even at a slower speed, risks syncope or a cardiac event, so the MA stops and alerts the provider with the crash cart ready.
Ref QB-QAU5E2Source: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: assist with stress test; signs of adverse reactionReport a problem with this question
17. A regular rhythm strip is recorded at the standard paper speed of 25 mm/sec. There are 4 large boxes between consecutive R waves. What is the heart rate?
- A.100 beats per minute
- B.120 beats per minute
- C.60 beats per minute
- D.75 beats per minute✓ Answer
At 25 mm/sec, each large box is 0.20 sec, so 300 large boxes pass in one minute; 300 divided by 4 large boxes equals 75 bpm. The small-box method agrees: 4 large boxes are 20 small boxes, and 1500 divided by 20 is 75.
Ref QB-7TNYTZSource: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: waveforms, intervals and calibration (paper speed and heart-rate calculation)Report a problem with this question
18. While labeling an EKG waveform for a new coworker, which pairing of a waveform component with the cardiac event it represents is correct?
- A.QRS: atrial repolarization only
- B.PR interval: ventricular repolarization
- C.P wave: ventricular depolarization
- D.T wave: ventricular repolarization✓ Answer
The T wave represents ventricular repolarization, the electrical recovery of the ventricles. The P wave is atrial depolarization, the QRS complex is ventricular depolarization (atrial repolarization is hidden inside it), and the PR interval spans atrial depolarization plus the conduction delay through the AV node.
Ref QB-MAS5WWSource: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: waveforms, intervals and segmentsReport a problem with this question
19. A rhythm strip on a 68-year-old woman shows an irregularly irregular rhythm with no distinct P waves and a wavy, fibrillatory baseline. She is alert and has no complaints. What is the appropriate action?
- A.Delete the tracing because the patient has no symptoms at all
- B.Treat it as artifact and repeat the tracing without reporting
- C.Note it on the tracing and report it to the provider promptly✓ Answer
- D.Tell the patient she has atrial fibrillation and needs treatment
An irregularly irregular rhythm with no distinct P waves is the classic pattern of atrial fibrillation, an abnormal rhythm the provider needs to know about even when the patient feels well. The MA performs, labels and reports the EKG but does not diagnose or discuss the interpretation with the patient, and a true rhythm finding is never discarded as artifact.
Ref QB-4TKYAWSource: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: recognize abnormal rhythms and report to the providerReport a problem with this question
20. A male patient with a hairy chest is scheduled for a 12-lead EKG. What is the correct skin preparation at the chest electrode sites?
- A.Shave the sites, clean off oils, and let the skin dry✓ Answer
- B.Wet the sites with water and apply electrodes at once
- C.Apply lotion so the electrodes slide into position
- D.Place electrodes over the hair and press down firmly
Electrodes need full, direct contact between the gel and clean, dry skin. Hair, oils, lotion and moisture all lift the electrode or raise skin impedance, which causes a wandering baseline or a lost signal, so the MA shaves the small site, cleans it with soap or alcohol, and lets it dry before applying the electrode.
Ref QB-F47ZZQSource: NHA CCMA Test Plan — Domain 3F EKG and Cardiovascular Testing: patient preparation and minimizing artifacts (skin prep)Report a problem with this question

1. A patient suspects early pregnancy, and the provider orders a urine hCG test. Which specimen instruction gives the most reliable result?

2. A patient begins a 24-hour urine collection at 7:00 a.m. Monday. What should the medical assistant tell the patient about the first void and the end of the collection?

3. During a workplace drug-screen collection, the donor hands the medical assistant the specimen cup. Under chain-of-custody procedure, what should the MA do next?

4. The provider orders a rapid strep test. How should the medical assistant collect the throat specimen?

5. A patient will collect a sputum specimen for culture at home. Which instruction is correct?

6. On a CLIA-waived rapid strep cassette, a line appears at the test (T) position, but no line appears at the control (C) position. How should the medical assistant handle the result?

7. To save time, a coworker suggests reading every pad of a CLIA-waived urine reagent strip at 30 seconds, even though the bottle chart lists different read times for different pads. Why is this unacceptable?

8. A urine specimen is tested correctly and the result is accurate, but the medical assistant enters the result into a different patient's chart. How is this error classified?

9. A 4-year-old who does not yet know the alphabet needs a distance visual acuity screening. Which approach should the medical assistant use?

10. During scratch (prick) allergy testing on the forearm, the medical assistant applies histamine and saline at labeled sites along with the allergens. At 15-20 minutes, the histamine site shows no wheal. What does this most likely indicate?

11. An asthma patient's personal best peak flow is 500 L/min. In the office she blows 330, 360 and 350 L/min with good technique. What should be recorded, and which zone does it fall in?

12. A patient's first spirometry effort is weak and stops after about 2 seconds, and air can be heard escaping through the nose. What should the medical assistant do?

13. During a resting 12-lead EKG, the tracing suddenly shows chaotic, irregular waves with no identifiable P waves, QRS complexes or T waves. What should the medical assistant do first?

14. A patient is being fitted with a Holter monitor for a 24-hour recording. Which instruction should the medical assistant give?

15. A patient reports brief palpitations that occur only once or twice a month. The provider wants a tracing captured during an episode. Which device fits this purpose?

16. During a treadmill stress test, the patient becomes pale and sweaty and says he feels dizzy. What should the medical assistant do?

17. A regular rhythm strip is recorded at the standard paper speed of 25 mm/sec. There are 4 large boxes between consecutive R waves. What is the heart rate?

18. While labeling an EKG waveform for a new coworker, which pairing of a waveform component with the cardiac event it represents is correct?

19. A rhythm strip on a 68-year-old woman shows an irregularly irregular rhythm with no distinct P waves and a wavy, fibrillatory baseline. She is alert and has no complaints. What is the appropriate action?

20. A male patient with a hairy chest is scheduled for a 12-lead EKG. What is the correct skin preparation at the chest electrode sites?

Other topics in this exam