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RPFT practice questions

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Question 1Patient Assessment and Preparation

Before any pulmonary function test begins, the technologist should first confirm the patient's identity and the ordered procedure by:

  1. verifying two identifiers against the order Correct answer.
  2. asking the patient to state a preferred nickname
  3. reviewing previous test results in the chart
  4. confirming the appointment time on the schedule

Explanation

Matching two independent identifiers, such as full name and date of birth or medical record number, to the written order prevents wrong-patient testing. A nickname or schedule entry alone does not reliably distinguish patients with similar names.

Question 2Patient Assessment and Preparation

Which action is the single most effective step in preventing transmission of respiratory pathogens between patients in the PFT laboratory?

  1. hand hygiene before and after each patient Correct answer.
  2. disinfecting the spirometer only once each day
  3. opening a window in the testing room
  4. wearing clean gloves for every maneuver

Explanation

Hand hygiene is the cornerstone of infection control and interrupts transfer of organisms from the technologist's hands and contaminated surfaces. Gloves do not replace hand hygiene, and routine disinfection schedules do not address person-to-person spread.

Question 3Patient Assessment and Preparation

When measuring standing height for use with spirometry reference equations, the patient should be instructed to:

  1. stand with the chin extended and shoulders relaxed
  2. stand with shoes on and heels slightly apart
  3. stand barefoot with heels together at the scale Correct answer.
  4. sit upright in the chair with the head level

Explanation

Accurate height requires the patient to stand barefoot with heels together, back against the stadiometer, and the head in the Frankfurt plane. Height is a major determinant of predicted values, so measurement error propagates directly into interpretation.

Question 4Patient Assessment and Preparation

A nose clip is applied during spirometry in order to:

  1. prevent air from escaping through the nose Correct answer.
  2. prevent the patient from biting the mouthpiece
  3. reduce the risk of the patient fainting
  4. keep the lips sealed tightly on the mouthpiece

Explanation

A nose clip ensures that all inspired and expired volume passes through the mouthpiece so that measured volumes reflect true lung volumes. Without it, nasal leakage produces falsely low values and inconsistent efforts.

Question 5Patient Assessment and Preparation

Which smoking information should be documented before interpreting pulmonary function results?

  1. current smoking status, pack-years, and quit date Correct answer.
  2. brand preference and cigarettes per pack only
  3. whether the patient has ever smoked marijuana
  4. the patient's opinion about the health effects of smoking

Explanation

Current smoking status, cumulative pack-years, and time since quitting all influence lung function and interpretation of obstructive and restrictive patterns. This information also guides pre-test instructions such as abstaining from smoking before DLCO.

Question 6Patient Assessment and Preparation

Informed consent for pulmonary function testing is obtained by:

  1. having the patient sign the order before any explanation
  2. explaining purpose and risks and confirming agreement Correct answer.
  3. asking the referring physician to sign on the patient's behalf
  4. recording verbal agreement from a family member by telephone

Explanation

Valid consent requires that the patient understand the purpose, risks, and alternatives and then voluntarily agree to proceed. The technologist documents this discussion; a signature without explanation is not informed consent.

Question 7Patient Assessment and Preparation

A patient uses albuterol before exercise. For routine spirometry, this short-acting beta-2 agonist is typically withheld for at least:

  1. 4 to 6 hours Correct answer.
  2. 1 hour
  3. 24 hours
  4. 2 hours

Explanation

Short-acting beta-2 agonists are generally withheld for 4 to 6 hours before spirometry so that the measured values reflect the patient's baseline airway caliber. Testing sooner may mask obstruction and confound interpretation.

Question 8Patient Assessment and Preparation

After a short-acting beta-2 agonist is given for reversibility testing, post-bronchodilator spirometry is usually obtained after:

  1. 10 to 15 minutes Correct answer.
  2. 1 to 2 minutes
  3. 30 minutes
  4. 3 to 5 minutes

Explanation

Peak bronchodilator response to a short-acting beta-2 agonist generally occurs within 10 to 15 minutes, so this interval is standard for post-bronchodilator testing. Waiting only a few minutes may miss the full response, while waiting 30 minutes or more is not required for these agents.

Question 9Patient Assessment and Preparation

Which finding in a patient's history is a relative contraindication to performing maximal forced expiratory maneuvers today?

  1. a chronic dry cough for several years
  2. asthma well controlled with an inhaler
  3. myocardial infarction three weeks ago Correct answer.
  4. mild hypertension treated with a diuretic

Explanation

Recent myocardial infarction is a relative contraindication because the vigorous effort and intrathoracic pressure changes increase cardiac demand and risk. Testing is typically deferred or undertaken only after cardiology consultation and clinical stabilization.

Question 10Patient Assessment and Preparation

To avoid a falsely low diffusing capacity measurement, the patient should be instructed to refrain from smoking for at least:

  1. 7 days before the test
  2. no specific period is needed
  3. 30 minutes before the test
  4. 24 hours before the test Correct answer.

Explanation

Cigarette smoke raises carboxyhemoglobin, which competes with carbon monoxide for hemoglobin binding sites and lowers the measured DLCO. A 24-hour abstinence period minimizes this acute effect.

Question 11Patient Assessment and Preparation

The modified Allen test is performed before radial artery puncture to evaluate:

  1. the presence of a radial artery aneurysm
  2. the clotting status of the patient's blood
  3. the patient's pain tolerance at the puncture site
  4. collateral circulation to the hand Correct answer.

Explanation

The modified Allen test assesses whether the ulnar artery can perfuse the hand if the radial artery is occluded or damaged by the puncture. Adequate collateral flow reduces the risk of ischemic complications.

Question 12Patient Assessment and Preparation

During measurement of thoracic gas volume in a body plethysmograph, the patient should be coached to:

  1. exhale completely and then pant against an open shutter
  2. take the deepest possible breath and hold it for 10 seconds
  3. support the cheeks and pant against a closed shutter Correct answer.
  4. breathe rapidly and shallowly through the mouthpiece

Explanation

Thoracic gas volume is derived from pressure changes generated while the patient pants against a closed shutter, with the cheeks supported to prevent mouth pressure from being dissipated. Panting at a low frequency of about 1 Hz produces reliable signals.

Question 13Patient Assessment and Preparation

Which variables are used to derive predicted spirometry values from standard reference equations?

  1. current medication use and smoking history
  2. age, height, sex, and race or ethnicity Correct answer.
  3. weight, body mass index, and physical activity level
  4. resting oxygen saturation and heart rate

Explanation

Modern spirometry reference equations are based on age, height, sex, and race or ethnicity, which together explain most of the variation in predicted values. Weight and clinical factors are not primary inputs to these equations.

Question 14Patient Assessment and Preparation

Before patient testing each day, spirometer volume calibration is verified by:

  1. injecting a 3-L syringe and checking accuracy within 3.5% Correct answer.
  2. measuring a coworker's vital capacity twice
  3. comparing the display to the manufacturer's serial number
  4. recording only the room temperature and barometric pressure

Explanation

A calibrated 3-L syringe is used to deliver a known volume, and the spirometer must record it within a defined tolerance, generally 3.5%. This check detects drift or leaks before results are collected.

Question 15Patient Assessment and Preparation

According to ATS/ERS standards, acceptable repeatability for FEV1 and FVC in adults is achieved when the two largest values are within:

  1. 250 mL
  2. 100 mL
  3. 150 mL Correct answer.
  4. 50 mL

Explanation

The current standard defines repeatability as the two largest FEV1 and FVC values falling within 150 mL of each other. Additional maneuvers are attempted until this criterion is met or a specified maximum number of efforts is reached.

Question 16Patient Assessment and Preparation

To optimize effort and safety during spirometry, the patient should be seated:

  1. standing with the neck extended and chin raised
  2. upright with feet flat and legs uncrossed Correct answer.
  3. in a reclining chair with the head supported
  4. leaning forward with elbows resting on the knees

Explanation

An upright seated posture with feet flat and legs uncrossed maximizes lung volumes and reduces the risk of falling during vigorous maneuvers. A chair with arms and a stable base is preferred.

Question 17Patient Assessment and Preparation

Which set of measurements should be obtained before and immediately after a 6-minute walk test?

  1. heart rate, SpO2, blood pressure, and dyspnea rating Correct answer.
  2. diffusing capacity and lung volumes by plethysmography
  3. arterial blood gas values and serum lactate levels
  4. peak cough flow and maximum inspiratory pressure at rest

Explanation

The 6-minute walk test is monitored with heart rate, oxygen saturation, blood pressure, and a dyspnea score such as the Borg scale before and after walking. These measures document physiologic response and safety.

Question 18Patient Assessment and Preparation

A patient scheduled for a methacholine challenge uses salmeterol daily. This long-acting beta-2 agonist should be withheld for at least:

  1. 4 hours
  2. 72 hours
  3. 1 week
  4. 24 to 48 hours Correct answer.

Explanation

Long-acting beta-2 agonists can blunt bronchial responsiveness and must be held longer than short-acting agents, typically 24 to 48 hours. Inadequate withholding can produce a false-negative challenge.

Question 19Patient Assessment and Preparation

During a walk test in a patient with COPD who is at risk of hypercapnia, supplemental oxygen should be titrated to maintain SpO2 at:

  1. above 98%
  2. 88% to 92% Correct answer.
  3. 80% to 85%
  4. 94% to 98%

Explanation

In patients with COPD who are at risk of carbon dioxide retention, oxygen is titrated to a target saturation of 88% to 92% to preserve hypoxic drive and avoid hypercapnia. Higher targets increase the risk of CO2 retention in this population.

Question 20Patient Assessment and Preparation

Which preparation is standard before a cardiopulmonary exercise test?

  1. giving a short-acting bronchodilator to every patient
  2. starting supplemental oxygen at 4 L/min for all patients
  3. asking the patient to exercise to exhaustion the previous day
  4. obtaining a resting 12-lead ECG and blood pressure Correct answer.

Explanation

Baseline electrocardiography and blood pressure establish the patient's cardiovascular status and provide a comparison for exercise responses. These measurements also help identify contraindications before testing begins.

Question 21Patient Assessment and Preparation

A patient with severe anemia has a measured DLCO of 60% of predicted. How should this result be interpreted and reported?

  1. the test should be repeated after a blood transfusion before reporting
  2. the measured DLCO should be reported without any adjustment
  3. the measured DLCO should be adjusted upward for the reduced hemoglobin Correct answer.
  4. the DLCO should be adjusted downward because anemia increases diffusivity

Explanation

Diffusing capacity depends on the volume of hemoglobin available to bind carbon monoxide, so anemia lowers the measured value even when the lungs are normal. Adjusting for the patient's hemoglobin raises the corrected DLCO and prevents overestimation of lung impairment.

Question 22Patient Assessment and Preparation

Spirometry volumes recorded at ambient temperature and pressure are converted to BTPS primarily because:

  1. BTPS correction compensates for the patient's altitude of residence
  2. the conversion removes the effect of the patient's body position
  3. gas volume varies with temperature, pressure, and water vapor saturation Correct answer.
  4. the correction adjusts for the viscosity of the exhaled gas

Explanation

A gas volume changes as it is warmed and humidified in the lungs, so results are standardized to body temperature, ambient pressure, and water vapor saturation. Without this conversion, values from different conditions could not be compared with reference equations.

Question 23Patient Assessment and Preparation

A patient with suspected active pulmonary tuberculosis arrives for spirometry. Which approach best protects staff and other patients?

  1. have the patient wear a surgical mask during the forced maneuvers
  2. use a filter in a negative-pressure room, scheduled last Correct answer.
  3. defer all testing until the patient has been treated for two weeks
  4. test in the usual room and disinfect the spirometer afterward

Explanation

Forced maneuvers generate aerosols and require airborne precautions, so testing should occur in a negative-pressure room with a bacterial/viral filter and be scheduled after other patients. Post-test disinfection alone does not protect against airborne transmission.

Question 24Patient Assessment and Preparation

During radial artery puncture the patient becomes pale, diaphoretic, and reports dizziness. The appropriate immediate action is to:

  1. raise the head of the bed and apply a cold compress
  2. give supplemental oxygen and wait for symptoms to pass
  3. stop, lay the patient flat, and monitor vital signs Correct answer.
  4. continue the puncture quickly to finish the sample

Explanation

These findings suggest a vasovagal reaction, which is managed by stopping the procedure, placing the patient supine to restore cerebral perfusion, and monitoring vital signs. The sample can be obtained later once the patient has recovered.

Question 25Patient Assessment and Preparation

A patient referred for a methacholine challenge has a baseline FEV1 of 62% of predicted. What is the most appropriate action?

  1. do not proceed with the challenge and notify the provider Correct answer.
  2. perform the challenge after giving a bronchodilator
  3. perform the challenge without the saline control step
  4. proceed but double the starting dose of methacholine

Explanation

A baseline FEV1 below 70% of predicted is a contraindication to methacholine challenge because of the risk of severe induced bronchoconstriction. The referring provider should be notified and an alternative evaluation considered.

Question 26Patient Assessment and Preparation

Before beginning any pulmonary function test, the technologist must confirm the patient's identity. Which pair of identifiers is appropriate?

  1. The diagnosis written on the requisition
  2. Full name and room number
  3. Full name and date of birth Correct answer.
  4. Medical record number alone

Explanation

Two independent identifiers are required, and the most reliable pair is the patient's full name plus a unique identifier such as date of birth or medical record number. Both must be confirmed verbally with the patient and matched to the requisition.

Question 27Patient Assessment and Preparation

Which description reflects correct standing height measurement for use in predicted-value equations?

  1. Shoes off, feet shoulder-width apart, head tilted back
  2. Shoes off, heels together, head positioned so the ear canal and lower orbit are level Correct answer.
  3. Shoes off, standing on the toes, chin tucked to the chest
  4. Shoes on, heels together, chin raised

Explanation

Accurate height requires the patient to stand barefoot with heels together against a vertical surface and the head in the Frankfort plane, in which a horizontal line connects the external ear canal and the lower orbital rim. Height directly drives predicted values, so small measurement errors propagate through every result.

Question 28Patient Assessment and Preparation

A patient with full upper dentures arrives for spirometry. What is the appropriate instruction regarding the dentures?

  1. Remove them to eliminate any risk of aspiration
  2. Leave them out and use a nasal mask instead of a mouthpiece
  3. Remove them so the mouthpiece can be inserted more deeply
  4. Leave well-fitting dentures in place during testing Correct answer.

Explanation

Well-fitting dentures support the oral structures and help maintain a leak-free seal around the mouthpiece, so they are kept in place. Only loose or ill-fitting dentures that might dislodge are removed.

Question 29Patient Assessment and Preparation

A patient discharged after an uncomplicated myocardial infarction 2 weeks ago is referred for spirometry. What is the most appropriate action?

  1. Perform only the post-bronchodilator portion of the test
  2. Perform the test now because the infarction was uncomplicated
  3. Postpone testing until at least 1 month after the event Correct answer.
  4. Perform the test with the patient lying supine

Explanation

Maximal forced maneuvers transiently raise myocardial workload and can provoke arrhythmias or ischemia, so recent myocardial infarction is a relative contraindication for roughly 4 weeks. The test is rescheduled after that interval once the patient is stable.

Question 30Patient Assessment and Preparation

A 62-year-old patient with severe kyphoscoliosis cannot stand for height measurement. Which approach best provides a value for use in predicted equations?

  1. Substitute body mass index for height
  2. Substitute a standard adult default of 170 cm
  3. Measure arm span and use it as a surrogate for height Correct answer.
  4. Use the height the patient reports from memory

Explanation

When standing height cannot be obtained because of spinal deformity, amputation, or inability to stand, measured arm span closely approximates height and is the recommended substitute. A default or reported value introduces systematic error into every predicted value.

Question 31Patient Assessment and Preparation

A patient reports a severe latex allergy. Which preparation is required before pulmonary function testing?

  1. Cancel all pulmonary function testing permanently for this patient
  2. Ask the patient to bring their own gloves while standard equipment is used
  3. Use latex-free gloves, mouthpiece, filter, and reservoir bag Correct answer.
  4. Use vinyl gloves but continue with latex mouthpieces and reservoir bags

Explanation

Latex exposure can trigger anaphylaxis in sensitized patients, so every item that contacts the patient or staff must be latex-free, including gloves, mouthpieces, filters, and rebreathing bags. The allergy is documented and communicated to all staff involved.

Question 32Patient Assessment and Preparation

Which dietary instruction should be given to a patient scheduled for a cardiopulmonary exercise test?

  1. Eat a light meal about 2 to 3 hours before the test Correct answer.
  2. Eat a large meal immediately before testing to ensure energy
  3. Skip all food and fluids on the day of the test
  4. Fast for 12 hours before the test

Explanation

A light meal taken 2 to 3 hours beforehand maintains glucose availability without causing splanchnic blood flow diversion, nausea, or discomfort during exercise. Prolonged fasting and heavy meals both degrade exercise performance and test quality.

Question 33Patient Assessment and Preparation

A patient arrives for spirometry with a temperature of 38.5 degrees Celsius, a productive cough, and generalized myalgias. What is the most appropriate action?

  1. Proceed with spirometry but omit the diffusing capacity
  2. Defer testing until the acute illness has resolved Correct answer.
  3. Perform the test in a negative-pressure room
  4. Proceed with testing as long as a filter is used

Explanation

Acute febrile illness reduces effort and alters measured lung function, and it raises the risk of transmitting infection to staff and other patients. Testing is rescheduled once the patient has recovered.

Question 34Patient Assessment and Preparation

Which piece of history is most important to obtain before radial artery puncture for blood gas analysis?

  1. The date of the patient's last spirometry
  2. Whether the patient has eaten in the past 4 hours
  3. Current use of anticoagulant therapy Correct answer.
  4. Family history of coronary artery disease

Explanation

Anticoagulants and known coagulopathy increase the risk of hematoma and bleeding at the puncture site, affecting site selection and the duration of post-puncture compression. This history is therefore part of the pre-procedure safety assessment.

Question 35Patient Assessment and Preparation

A patient is referred for spirometry 10 days after uncomplicated cataract surgery. What is the most appropriate action?

  1. Perform only a slow vital capacity instead of forced maneuvers
  2. Delay testing for at least 4 weeks after the surgery Correct answer.
  3. Proceed with the full test as scheduled
  4. Delay testing for 24 hours

Explanation

Forced expiratory maneuvers raise intraocular pressure, so recent eye surgery is a relative contraindication for approximately one month. Testing is deferred until the surgical site has healed sufficiently.

Question 36Patient Assessment and Preparation

A patient is scheduled for baseline spirometry, diffusing capacity, and post-bronchodilator spirometry during a single visit. Which sequence is correct?

  1. Baseline spirometry, diffusing capacity, post-bronchodilator spirometry Correct answer.
  2. Post-bronchodilator spirometry, diffusing capacity, baseline spirometry
  3. Post-bronchodilator spirometry, baseline spirometry, diffusing capacity
  4. Diffusing capacity, post-bronchodilator spirometry, baseline spirometry

Explanation

Baseline spirometry is obtained first, the diffusing capacity is measured before any bronchodilator is given, and the bronchodilator is administered last so that the post-bronchodilator spirometry can be performed. Giving a bronchodilator early would confound both the baseline and diffusing capacity measurements.

Question 37Patient Assessment and Preparation

Which practice best minimizes cross-contamination between patients undergoing spirometry?

  1. Rinsing the mouthpiece in tap water and drying it with a cloth
  2. Using a new single-use filter and mouthpiece for each patient and disinfecting reusable parts as directed Correct answer.
  3. Wiping the mouthpiece with alcohol between patients
  4. Reusing the same in-line filter for all patients on the same day once it has air-dried overnight

Explanation

Single-use barriers such as a bacterial/viral filter and mouthpiece, combined with disinfection of reusable components according to the manufacturer's instructions, is the accepted approach to infection control. Barriers are never reused between patients.

Question 38Patient Assessment and Preparation

A patient scheduled for a maximal cardiopulmonary exercise test arrives with a temperature of 38.6 degrees Celsius, a resting heart rate of 118 beats per minute, and malaise. What is the best action?

  1. Give an antipyretic, wait 10 minutes, and proceed
  2. Proceed because fever has little effect on exercise performance
  3. Proceed but use a shortened exercise protocol
  4. Notify the supervising physician and defer the test Correct answer.

Explanation

Acute febrile illness with resting tachycardia is a contraindication to maximal exercise testing because it increases cardiac and metabolic demand and risks arrhythmia or collapse. The supervising physician is informed and the test is rescheduled after recovery.

Question 39Patient Assessment and Preparation

A patient with moderate dementia cannot consistently follow the breathing instructions for spirometry. What is the most appropriate action?

  1. Document the limitation and consult the ordering provider about whether testing can be performed or modified Correct answer.
  2. Perform the test and report the values as valid
  3. Report predicted values in place of measured values
  4. Ask the caregiver to perform the forced maneuvers in place of the patient while the patient watches

Explanation

Valid spirometry depends on the patient's ability to understand and cooperate with the forced maneuver, so an inability to follow instructions must be documented and discussed with the ordering provider. A surrogate cannot perform the maneuver, and predicted values are never substituted for measured values.

Question 40Patient Assessment and Preparation

A patient scheduled for body plethysmography reports severe claustrophobia. Which preparation is most appropriate?

  1. Administer a sedative before the patient enters the box
  2. Explain each step and remain in the patient's view throughout the test Correct answer.
  3. Cancel testing permanently and note the phobia in the record
  4. Close the door quickly without explanation to shorten exposure time

Explanation

Anxiety increases irregular breathing and panting artifacts, so the technologist explains the procedure beforehand, allows the patient to become familiar with the enclosure, and stays visible during testing. Reassurance and a calm, stepwise approach improve both comfort and test quality.

Question 41Equipment Quality Control and Calibration

Which device is the standard for daily volume calibration verification of a pulmonary function spirometer?

  1. A calibrated 3-L syringe Correct answer.
  2. A rotameter flowmeter
  3. A 1-L volumetric flask
  4. A water-sealed spirometer

Explanation

A calibrated 3-L syringe is the standard volume standard for daily spirometer verification because it delivers a known volume that can be compared with the spirometer reading. The check confirms that the device measures volume within accepted tolerance before patient testing.

Question 42Equipment Quality Control and Calibration

How often should a spirometer's volume calibration be verified with a 3-L syringe in a busy PFT laboratory?

  1. Before each patient is tested
  2. At least once each testing day Correct answer.
  3. Once each month
  4. Once each week

Explanation

Standards require spirometer volume verification at least daily before patient testing, with more frequent checks if the device is unstable or after sensor changes. Daily verification detects drift before it affects clinical results.

Question 43Equipment Quality Control and Calibration

A daily 3-L syringe check is acceptable when the measured volume falls within which range?

  1. 2.895 to 3.105 L Correct answer.
  2. 2.970 to 3.030 L
  3. 2.700 to 3.300 L
  4. 2.850 to 3.150 L

Explanation

The accepted tolerance is ±3.5% of the 3-L syringe volume, which equals ±0.105 L. Therefore the acceptable range is 2.895 to 3.105 L.

Question 44Equipment Quality Control and Calibration

Which reference gas is used to set the span on the carbon monoxide analyzer of a DLCO system?

  1. 100% oxygen
  2. 0.3% carbon monoxide Correct answer.
  3. 21% oxygen
  4. 5% carbon dioxide

Explanation

The CO analyzer span is set with a reference gas containing a known CO concentration, commonly about 0.3% CO. This establishes the analyzer's response to the test gas concentration used during DLCO testing.

Question 45Equipment Quality Control and Calibration

When zeroing an infrared gas analyzer before testing, which gas is typically used?

  1. Exhaled air from a healthy subject
  2. 100% nitrogen for all analyzers
  3. A gas free of the measured analyte Correct answer.
  4. The calibration span gas

Explanation

Zeroing sets the analyzer's baseline using a gas that contains none of the analyte being measured, such as room air for a CO analyzer. The span gas is then used to set the upper calibration point.

Question 46Equipment Quality Control and Calibration

What is the main purpose of a biological control program in the PFT laboratory?

  1. To determine the patient's predicted values
  2. To detect changes in equipment or technician performance over time Correct answer.
  3. To verify that the calibration syringe is accurate
  4. To calibrate the gas analyzers each morning

Explanation

A biological control uses repeated measurements from a healthy stable subject and compares them with baseline values. This helps detect gradual equipment drift or changes in testing technique that may not be evident from calibration checks alone.

Question 47Equipment Quality Control and Calibration

Which ambient measurement is required with temperature and humidity to correct gas volumes to BTPS?

  1. Carbon dioxide concentration
  2. Airflow resistance
  3. Barometric pressure Correct answer.
  4. Oxygen saturation

Explanation

BTPS correction requires ambient temperature, water vapor pressure or humidity, and barometric pressure. These values allow measured gas volumes to be converted to body temperature, ambient pressure, saturated conditions.

Question 48Equipment Quality Control and Calibration

How is a leak test usually performed on a spirometer?

  1. By comparing two gas analyzers
  2. By measuring a known volume with a 3-L syringe
  3. By recording barometric pressure
  4. By occluding the mouthpiece and applying positive pressure Correct answer.

Explanation

A leak test applies positive pressure to an occluded system and observes whether the pressure is maintained. A rapid pressure loss indicates a leak that must be corrected before volume measurements are reliable.

Question 49Equipment Quality Control and Calibration

A technologist injects 3.00 L from a calibrated syringe and the spirometer records 2.88 L. What is the appropriate interpretation?

  1. It is acceptable because the error is under 5%
  2. It is acceptable if the room is warm
  3. It fails the ±3.5% accuracy limit Correct answer.
  4. The syringe is the likely source of error

Explanation

The recorded volume is 0.12 L low, which is a 4.0% error. Because this exceeds the ±3.5% acceptance limit, the spirometer requires recalibration or service before patient testing.

Question 50Equipment Quality Control and Calibration

After a flow sensor is replaced on a spirometer, what should be done before testing patients?

  1. Nothing if the sensor is factory calibrated
  2. Only a leak test
  3. A volume calibration and linearity check Correct answer.
  4. Only a biological control

Explanation

Replacing a flow sensor changes the device's calibration, so volume accuracy and flow linearity must be verified before clinical use. Factory calibration does not account for the sensor's installation in the specific system.