CABT Clinical Procedures & Techniques 2 — Questions and Answers
Question 1: During a 12-lead ECG procedure, which electrode placement is considered the reference point (Wilson's central terminal) for augmented unipolar limb leads?
- Right arm electrode only
- Average of right arm, left arm, and left leg electrodes (Correct answer)
- Left arm and left leg electrodes combined
- Sternum midpoint electrode
Correct answer: Average of right arm, left arm, and left leg electrodes
Wilson's central terminal averages the potentials from RA, LA, and LL electrodes to create a near-zero reference for augmented leads (aVR, aVL, aVF).
Question 2: A biomedical technician is calibrating a spirometer. The primary performance verification standard for volume accuracy requires the device to be within what tolerance?
- ±1% of reading
- ±3.5% of reading or 65 mL (whichever is greater) (Correct answer)
- ±5% of reading
- ±10 mL absolute
Correct answer: ±3.5% of reading or 65 mL (whichever is greater)
ATS/ERS standards require spirometer volume accuracy within ±3.5% of reading or ±65 mL, whichever is greater.
Question 3: When performing a blood glucose meter accuracy check per ISO 15197:2013, what percentage of results must fall within ±15 mg/dL (for concentrations <100 mg/dL) or ±15%?
- 85%
- 90%
- 95% (Correct answer)
- 99%
Correct answer: 95%
ISO 15197:2013 requires 95% of blood glucose meter results to meet the specified accuracy criteria compared to a reference method.
Question 4: Which sterilization method is most appropriate for heat-sensitive flexible endoscopes?
- Steam autoclave at 134°C
- Dry heat oven at 160°C
- Ethylene oxide (EtO) or hydrogen peroxide gas plasma (Correct answer)
- UV radiation chamber
Correct answer: Ethylene oxide (EtO) or hydrogen peroxide gas plasma
EtO and hydrogen peroxide gas plasma are low-temperature sterilization methods suitable for heat-sensitive endoscopes that cannot withstand steam autoclaving.
Question 5: During phlebotomy, the tourniquet should be released within what timeframe to prevent hemoconcentration artifacts in laboratory results?
- 30 seconds
- 1 minute (Correct answer)
- 2 minutes
- 5 minutes
Correct answer: 1 minute
Tourniquets should be released within 1 minute of application to prevent hemoconcentration, which can falsely elevate cell counts, proteins, and other analytes.
Question 6: A patient's pulse oximeter reads 98% SpO2 but the patient appears cyanotic. Which condition could MOST likely cause this discrepancy?
- Hypercapnia
- Carbon monoxide poisoning (Correct answer)
- Iron deficiency anemia
- Hypothyroidism
Correct answer: Carbon monoxide poisoning
Pulse oximeters cannot distinguish carboxyhemoglobin from oxyhemoglobin, so CO poisoning causes falsely elevated SpO2 readings despite severe hypoxia.
Question 7: When setting up a continuous passive motion (CPM) device post-knee surgery, which parameter is adjusted FIRST before range-of-motion settings?
- Speed of cycling
- Flexion angle limit
- Limb length/segment alignment (Correct answer)
- Pause time at end range
Correct answer: Limb length/segment alignment
Proper limb segment alignment in the CPM device must be confirmed first to ensure the mechanical joint axis matches the anatomical joint axis and prevent injury.
CABT Clinical Procedures & Techniques 2
During a 12-lead ECG procedure, which electrode placement is considered the reference point (Wilson's central terminal) for augmented unipolar limb leads?