What is Pulmonary Function Tests: Purpose, Procedure, Results & Costs in India

In India, respiratory health is a growing concern, with conditions like asthma, Chronic Obstructive Pulmonary Disease (COPD), and various occupational lung diseases affecting millions. Early diagnosis and effective management are crucial for a better quality of life. This is where Pulmonary Function Tests (PFTs) play an indispensable role. PFTs are a group of non-invasive diagnostic procedures that provide vital insights into how well your lungs are working. They are the cornerstone for diagnosing, monitoring, and managing a wide array of respiratory conditions, helping both patients and healthcare providers make informed decisions.

For patients across India, understanding PFTs – what they are, why they are performed, how to prepare, what the procedure involves, and how to interpret the results – is key to actively participating in their healthcare journey. This comprehensive guide will delve into these aspects, specifically highlighting their relevance and accessibility within the Indian healthcare landscape, including typical costs and the importance of Indian-specific reference data.

What are Pulmonary Function Tests?

Pulmonary Function Tests (PFTs) encompass a series of sophisticated, non-invasive measurements designed to assess the mechanical function of your lungs, airways, and respiratory muscles. Essentially, they evaluate your lung capacity, airflow rates, and the efficiency of gas exchange within your lungs. Imagine your lungs as a pair of bellows; PFTs measure how much air these bellows can hold, how quickly they can push air out, and how efficiently they can transfer oxygen into your blood and remove carbon dioxide.

These tests are crucial because they provide objective, quantifiable data about your respiratory system. Unlike simply listening to your breathing, PFTs offer precise numbers that can reveal subtle abnormalities long before symptoms become severe. They don't just tell you if there's a problem, but also what kind of problem it is (e.g., difficulty getting air in, difficulty getting air out, or difficulty exchanging gases), and how severe it might be.

The spectrum of PFTs includes several distinct tests, each providing a unique piece of the puzzle regarding lung health. The most commonly performed PFT is spirometry, which focuses on airflow dynamics. However, a comprehensive evaluation often involves other tests like lung volume measurements, diffusion capacity tests, and sometimes more specialized assessments, all contributing to a holistic understanding of your pulmonary status. For accurate and standardized practices across India, organizations like the Indian Chest Society and the National College of Chest Physicians (India) have established guidelines, particularly for spirometry, ensuring consistent quality of care.

Why are Pulmonary Function Tests Performed?

Pulmonary Function Tests serve multiple critical purposes in modern medicine, particularly in the Indian context where respiratory diseases are prevalent. They are not merely diagnostic tools but also instrumental in the long-term management and prevention of lung conditions.

• 1. Diagnosis of Respiratory Disorders: PFTs are often the first line of investigation when a respiratory disorder is suspected. They help physicians:

  • Identify and Differentiate Conditions: For instance, distinguishing between asthma (often reversible airway obstruction) and Chronic Obstructive Pulmonary Disease (COPD) (largely irreversible obstruction) is crucial for appropriate treatment. They can also pinpoint other conditions like emphysema, chronic bronchitis, pulmonary fibrosis (a restrictive lung disease), and bronchiectasis.
  • Confirm a Diagnosis: When symptoms like persistent cough, wheezing, or shortness of breath are present, PFTs provide objective evidence to confirm or rule out a lung condition.
  • Characterize the Nature of the Problem: They can determine if the lung problem is "obstructive" (difficulty exhaling air due to narrowed airways) or "restrictive" (difficulty inhaling enough air due to stiff lungs or chest wall limitations).

• 2. Monitoring Disease Progression: For individuals living with chronic lung conditions, PFTs are invaluable for tracking the natural course of the disease. Regular PFTs help doctors assess:

  • Worsening or Improvement: They can objectively show if a condition like COPD or pulmonary fibrosis is progressing, remaining stable, or responding positively to interventions.
  • Long-term Trends: Serial measurements over time allow healthcare providers to identify trends and adjust management strategies proactively.

• 3. Evaluating Treatment Effectiveness: PFTs are a key metric for determining whether prescribed medications and therapies are working.

  • Medication Efficacy: For example, in asthma, a significant improvement in airflow after using a bronchodilator indicates the medication is effective.
  • Therapy Adjustments: If PFT results show no improvement or a decline, it signals to the doctor that the current treatment plan may need modification, dosage adjustment, or a different therapeutic approach.

• 4. Pre-operative Assessment: Before certain surgeries, especially cardiothoracic, upper abdominal, and other major procedures, PFTs are performed to assess a patient's respiratory reserve and identify potential post-operative risks.

  • Risk Stratification: Patients with poor lung function are at a higher risk of complications like pneumonia or respiratory failure after surgery. PFTs help surgeons and anesthesiologists evaluate this risk.
  • Optimization of Lung Health: If PFTs reveal significant impairment, steps can be taken before surgery to optimize lung health, potentially reducing complications.

• 5. Screening for Occupational Lung Diseases: In India, many workers are exposed to hazardous substances in various industries. PFTs are recommended for individuals exposed to:

  • Dusts and Fumes: Such as sawdust, coal dust, asbestos fibers, graphite, silica, and chemical fumes from paint or other industrial agents.
  • Early Detection: Regular screening helps detect early signs of occupational lung diseases (e.g., asbestosis, silicosis, coal worker's pneumoconiosis) before symptoms become debilitating, allowing for timely intervention and workplace modifications.

• 6. Investigating Symptoms: When patients present with unexplained respiratory symptoms, PFTs help determine the underlying cause. These symptoms include:

  • Chronic Cough: A persistent cough without an obvious cause.
  • Wheezing: A whistling sound during breathing, often indicative of narrowed airways.
  • Shortness of Breath (Dyspnea): Difficulty breathing, especially during exertion. PFTs can help differentiate between cardiac and pulmonary causes of dyspnea.
  • Chest Tightness: A feeling of constriction in the chest.

By providing objective data, PFTs empower healthcare providers to accurately diagnose, effectively manage, and proactively prevent the progression of respiratory conditions, ultimately enhancing patient care in India.

Preparation for Pulmonary Function Tests

Accurate PFT results depend heavily on proper patient preparation. Adhering to specific guidelines ensures that the measurements reflect your true lung function and are not skewed by external factors. Your doctor or the diagnostic center will provide detailed instructions, but here are the general preparations typically advised for Indian patients:

• 1. Avoid Heavy Meals: It is generally advised to avoid eating a heavy meal for at least 4-6 hours before the test. A full stomach can push against the diaphragm, making it difficult to take a maximal deep breath and perform forceful exhalations, which are critical for accurate spirometry. A light snack a few hours before is usually acceptable.

• 2. Refrain from Smoking: Smoking should be avoided for at least four hours, and ideally 24 hours, prior to the test. Nicotine and other chemicals in cigarettes can cause temporary narrowing of the airways (bronchoconstriction), affect gas exchange, and irritate the respiratory system, leading to inaccurate readings.

• 3. Avoid Caffeine Intake: Refrain from consuming caffeine for at least four hours before the test. Caffeine, found in coffee, tea, certain soft drinks, and energy drinks, can have mild bronchodilatory effects, potentially altering airway measurements and affecting the test's validity.

• 4. Discuss Medications with Your Doctor: This is one of the most crucial steps. Your physician will provide specific instructions regarding your medications, especially bronchodilators.

  • Bronchodilators: These medications relax and open the airways. Depending on the purpose of the test (e.g., to assess baseline lung function or bronchodilator responsiveness), you may be asked to withhold short-acting bronchodilators (like salbutamol/albuterol) for 4-8 hours and long-acting bronchodilators (like formoterol, salmeterol, tiotropium) for 12-24 hours prior to the test. Never stop any medication without explicit instructions from your doctor.
  • Other Medications: Inform your doctor about all other medications, vitamins, and supplements you are taking, as some might subtly influence lung function or interact with the test procedure.

• 5. Avoid Vigorous Exercise: Do not engage in strenuous physical activity for at least 30 minutes to an hour before the test. Vigorous exercise can temporarily alter breathing patterns, increase heart rate, and lead to fatigue, which might affect your ability to perform the forceful breathing maneuvers required.

• 6. Wear Loose, Comfortable Clothing: Choose clothing that does not restrict your chest and abdominal movement. Tight clothing can make it difficult to take a full deep breath and exhale completely, impacting the accuracy of lung volume measurements.

• 7. Remove Prosthetic Loose Dentures: If you wear loose dentures, you may be asked to remove them before the test. This ensures a tight seal around the mouthpiece of the spirometer, preventing air leakage during the breathing maneuvers. Fixed dentures are generally not an issue.

• 8. Bring a List of Current Medications: Always carry an updated list of all your current medications, including dosage and frequency. This information is vital for the interpreting physician to correlate your PFT results with your medical history and current treatment regimen.

• 9. Inform the Technician of Any Recent Illnesses: If you have had a recent respiratory infection (like a cold, flu, or active tuberculosis), or are experiencing symptoms like a severe cough or fever, inform the diagnostic center. The test may need to be postponed to ensure accurate results and prevent the spread of infection.

By diligently following these preparation guidelines, you contribute significantly to obtaining reliable PFT results, which in turn leads to a more accurate diagnosis and effective management of your respiratory health.

The Pulmonary Function Tests Procedure

Pulmonary Function Tests are typically conducted in a specialized PFT laboratory or diagnostic center by trained technicians under the supervision of a pulmonologist. The process is generally comfortable, though some maneuvers require significant effort.

• General Setup:
  • You will usually be seated comfortably in a quiet room.
  • A soft nose clip will be placed on your nose to ensure all air passes through your mouth.
  • You will be instructed to breathe into a sterile mouthpiece connected to the PFT machine (spirometer or other specialized equipment).
  • The technician will provide clear, step-by-step instructions and encouragement throughout the test. Formal training for personnel (physicians and technicians) conducting spirometry is strongly recommended by Indian guidelines to ensure proper technique and accurate results.

Now, let's look at the specific types of PFTs you might undergo:

• 1. Spirometry (The Most Common PFT):

  • Spirometry measures how much air you can inhale and exhale, and how quickly. It's an effort-dependent test, meaning your cooperation is key.
  • Procedure:
    • You will be asked to take the deepest breath possible, filling your lungs completely.
    • Then, you will place your lips tightly around the mouthpiece.
    • You will be instructed to exhale as forcefully and completely as you can, for as long as you can (usually at least 6 seconds, sometimes longer for patients with obstructive disease).
    • After a brief rest, you may be asked to repeat this maneuver several times.
    • Acceptable Spirograms: For accurate results, at least three acceptable spirograms should be obtained during a session, showing consistent and maximal effort. The technician will guide you to ensure you perform the maneuver correctly.
  • Bronchodilator Reversibility Test: Sometimes, spirometry is performed before and after administering a bronchodilator medication (e.g., salbutamol) through an inhaler. This helps determine if airway obstruction is reversible, which is crucial for diagnosing asthma.

• 2. Lung Volume Measurement:

  • Spirometry cannot measure all lung volumes, such as the air remaining in your lungs after a maximal exhalation (Residual Volume, RV). For a complete picture, lung volume measurements are used.
  • Techniques:
    • Body Plethysmography: This is the most accurate method. You sit in an airtight, telephone-booth-like chamber. As you breathe, changes in pressure and volume inside the box and your lungs are measured, allowing the machine to calculate Total Lung Capacity (TLC), Functional Residual Capacity (FRC), and Residual Volume (RV).
    • Nitrogen Washout or Helium Dilution: These gas dilution techniques involve breathing a known concentration of a tracer gas (like nitrogen or helium) for several minutes. The change in gas concentration helps calculate lung volumes.
  • Purpose: These tests determine the total amount of air your lungs can hold (TLC) and help differentiate between obstructive and restrictive lung diseases, as spirometry alone cannot confirm a restrictive pattern.

• 3. Diffusion Capacity Test (DLCO - Diffusing Capacity of the Lung for Carbon Monoxide):

  • This test evaluates how efficiently oxygen and carbon dioxide move from the air sacs (alveoli) in your lungs into your bloodstream. It assesses the integrity of the alveolar-capillary membrane.
  • Procedure: You take a single, deep breath of a gas mixture containing a very small, harmless amount of carbon monoxide (a tracer gas). You hold your breath for about 10 seconds, then exhale. The amount of carbon monoxide absorbed into your blood is measured.
  • Purpose: A reduced DLCO can indicate conditions that affect the lung tissue or blood vessels, such as emphysema, pulmonary fibrosis, pulmonary hypertension, or anemia.

• 4. Impulse Oscillation Testing (IOS):

  • IOS is a less effort-dependent PFT, particularly useful for children, elderly patients, or those unable to perform forced maneuvers accurately.
  • Procedure: You simply breathe normally through a mouthpiece while the device sends small pressure waves (oscillations) into your airways.
  • Purpose: It assesses airway resistance and reactance (stiffness), providing information about the mechanics of both large and small airways, which can aid in diagnosing conditions like asthma or COPD.

• 5. Arterial Blood Gas Analysis (ABG):

  • While technically not a PFT in the same vein as spirometry, ABG is often considered part of a comprehensive respiratory evaluation.
  • Procedure: A small sample of blood is drawn from an artery (usually in the wrist).
  • Purpose: It measures the levels of oxygen (pO2) and carbon dioxide (pCO2) in your blood, as well as blood pH and bicarbonate levels. This test provides immediate information about your body's acid-base balance and the severity of respiratory failure.

The entire PFT session can take anywhere from 30 to 90 minutes, depending on the specific tests ordered. Throughout the procedure, the technician will monitor you for any discomfort and ensure your safety.

Understanding Results

Interpreting Pulmonary Function Test results is a sophisticated process performed by a pulmonologist or a physician with specialized training in respiratory medicine. It involves comparing your measured values against established norms and considering your individual clinical context.

• 1. Comparison to Predicted Values and Lower Limits of Normal (LLN):

  • Your PFT results are not assessed in isolation. They are compared to "predicted values" – what is considered normal for a person of your age, gender, height, and ethnicity.
  • The "Lower Limit of Normal (LLN)" is a statistically derived threshold below which your lung function is considered abnormal.
  • Importance of Indian-Specific Reference Equations: This is a crucial aspect for patients in India. Applying international or Caucasian reference values can lead to significant misdiagnosis or misinterpretation in the Indian population. Due to genetic, environmental, and lifestyle differences, Indian individuals often have different lung capacities and flow rates compared to Western populations. Reputable guidelines from the Indian Chest Society emphasize the use of appropriate, region-specific reference equations to ensure accurate diagnosis and management.

• 2. Key Spirometric Variables: The primary values derived from spirometry are central to interpretation:

  • Forced Vital Capacity (FVC): This is the total amount of air you can forcefully exhale after taking the deepest possible breath. It represents your total lung capacity that can be exhaled.
  • Forced Expiratory Volume in 1 second (FEV1): This is the volume of air you can forcefully exhale during the first second of the FVC maneuver. It's a measure of how quickly you can move air out of your lungs.
  • FEV1/FVC Ratio: This ratio is a clinically vital index. It tells us what percentage of your total forced exhalation occurs in the first second. A low ratio indicates airflow obstruction.

• 3. Categorization of Abnormalities: Based on these variables, PFT results are typically categorized into patterns:

  • Obstructive Ventilatory Defect:
    • Characteristic: FEV1/VC (or FEV1/FVC) less than the Lower Limit of Normal (LLN). This indicates difficulty in exhaling air quickly due to narrowed or obstructed airways.
    • What it means: Air gets trapped in the lungs, making it harder to empty them efficiently.
    • Common conditions: Asthma, Chronic Obstructive Pulmonary Disease (COPD - including emphysema and chronic bronchitis), bronchiectasis.
    • Further testing: Often followed by a bronchodilator reversibility test to differentiate between reversible (e.g., asthma) and largely irreversible (e.g., COPD) obstruction.
  • Restrictive Ventilatory Defect:
    • Characteristic: Suggested by a Vital Capacity (VC, which can be FVC or Slow VC) below the LLN, but with a normal or even increased FEV1/VC ratio. Confirmation usually requires lung volume measurements (e.g., TLC below LLN).
    • What it means: The lungs cannot expand fully, or the chest wall is stiff, leading to reduced total lung capacity.
    • Common conditions: Pulmonary fibrosis, sarcoidosis, obesity, neuromuscular disorders (e.g., muscular dystrophy), chest wall deformities.
  • Mixed Ventilatory Defect:
    • Involves elements of both obstruction and restriction, meaning both airflow is limited, and lung volumes are reduced.

• 4. Severity of Impairment: Once an abnormality (obstructive or restrictive) is identified, its severity is assessed, typically based on FEV1 values for obstruction and VC or TLC for restriction:

  • Mild: FEV1 or VC ≥ 70% of the predicted value.
  • Moderate: FEV1 or VC 50%–69% of the predicted value.
  • Severe: FEV1 or VC < 50% of the predicted value. This categorization helps guide treatment decisions and predict prognosis.

• 5. Other PFTs:

  • Lung Volumes (TLC, RV): Confirm restrictive patterns or identify hyperinflation (air trapping) in obstructive diseases.
  • DLCO: Assesses gas exchange. Reduced DLCO can indicate emphysema, interstitial lung disease, or pulmonary vascular disease.
  • IOS: Provides detailed information on airway resistance in different parts of the lungs, especially useful in patients who cannot perform spirometry.
  • ABG: Measures blood oxygen and carbon dioxide, providing insights into the severity of respiratory failure.

Ultimately, your doctor will integrate these PFT results with your medical history, physical examination, imaging studies (like X-rays or CT scans), and other laboratory tests to arrive at a comprehensive diagnosis and formulate the most appropriate treatment plan tailored to your specific needs.

Risks

Pulmonary Function Tests are widely regarded as safe, non-invasive procedures with minimal risks. The discomfort experienced is usually transient and mild. However, it's important to be aware of the potential minor side effects and certain conditions that may warrant caution or contraindicate the test.

• Minor Side Effects (Generally Mild and Temporary):

  • Dizziness or Lightheadedness: This can occur due to the forceful and rapid breathing maneuvers, leading to hyperventilation. It usually subsides quickly with rest.
  • Temporary Shortness of Breath: Some individuals, especially those with pre-existing respiratory conditions, might experience transient shortness of breath during or immediately after the forceful breathing.
  • Mild Discomfort: Performing deep breaths and forced exhalations repeatedly can cause temporary chest or abdominal muscle strain, leading to mild discomfort.
  • Coughing: The forced exhalation can sometimes trigger a cough reflex, especially in individuals with sensitive airways.
  • Asthma Attack (Rare): In very rare instances, the vigorous breathing maneuvers might trigger a mild asthma attack in highly susceptible individuals. The PFT lab is equipped to manage such situations.
  • Fatigue: The effort required for some tests can be tiring, particularly for elderly patients or those with severe lung disease.

• Contraindications and Precautions (When PFTs Might Be Risky or Inadvisable): Certain medical conditions may increase the risk associated with PFTs or make the test results unreliable. It is crucial to inform your doctor and the PFT technician about any of the following:

  • Recent Thoraco-abdominal or Eye Surgery: The increased intrathoracic and intra-abdominal pressure generated during forceful breathing maneuvers can pose a risk. This includes recent cataract surgery or any surgery where increased pressure might be detrimental (e.g., within 3-6 months).
  • Unstable Heart Conditions:
    • Recent Myocardial Infarction (Heart Attack): PFTs are generally avoided within one month of a heart attack due to the potential strain on the heart.
    • Unstable Angina: Chest pain that is worsening or occurring at rest.
    • Uncontrolled Hypertension: Very high blood pressure.
    • Recent Stroke: Increased intracranial pressure can be a concern.
    • Recent Cardiac Surgery: Similar to other major surgeries, a recovery period is needed.
  • Cerebral or Aortic Aneurysms: The increased pressure during forceful exhalation could theoretically increase the risk of rupture.
  • Active Hemoptysis: Coughing up blood. Performing PFTs could worsen bleeding.
  • Active Pneumothorax: A collapsed lung. PFTs can exacerbate the condition.
  • Dementia or Confused Patients: Individuals who are unable to understand or follow complex instructions may not be able to perform the maneuvers accurately, leading to unreliable results. Alternative tests like IOS might be considered.
  • Active Respiratory Infections:
    • Active Tuberculosis (TB): PFTs should be postponed to prevent the spread of airborne infection to healthcare personnel and other patients, and because acute infection can skew results.
    • Flu, Severe Cough, or Cold: Similar to TB, these conditions can lead to inaccurate results and pose an infection risk. It's generally advised to wait until symptoms resolve.
  • Severe Nausea or Vomiting: The forceful breathing could induce or worsen these symptoms.

Before scheduling a PFT, your doctor will review your medical history to ensure the test is safe and appropriate for you. Open communication with your healthcare provider about your health status and any concerns is paramount.

Costs in India

The cost of Pulmonary Function Tests in India can vary significantly, reflecting the diverse healthcare landscape across the country. Factors influencing the price include the city, the type of facility (e.g., large corporate hospital, smaller diagnostic center, government hospital), the specific PFTs included in the package, and the expertise of the interpreting physician.

Generally, the price for a basic PFT (spirometry) in India ranges from approximately ₹800 to ₹2,500. However, some sources indicate a wider range, with costs potentially starting as low as ₹440 for basic spirometry in smaller centers or specific regions, and going up to ₹4,000 or more for a comprehensive PFT panel including lung volumes and diffusion capacity tests in premium facilities.

Here's an approximate breakdown of costs in various Indian cities based on available data, keeping in mind these are indicative and can fluctuate:

• Hyderabad: ₹440 to ₹2,200
• Bhubaneswar: ₹800 to ₹1,200
• Nagpur: ₹900 to ₹1,200
• Raipur: ₹1,200 to ₹2,000
• Indore and Aurangabad: ₹1,200 to ₹2,200
• Visakhapatnam: ₹1,200 to ₹2,500
• Delhi (NCR): ₹600 to ₹3,720 (for a comprehensive panel in some facilities)
• Bangalore/Bengaluru: Approximately ₹700 to ₹2,500
• Mumbai: ₹1,000 to ₹3,000 (depending on the facility and specific tests)
• Chennai: ₹800 to ₹2,500
• Kolkata: ₹700 to ₹2,000

Factors Influencing the Cost:

• Type of Test: Spirometry alone is usually less expensive than a full PFT panel that includes lung volume measurements (plethysmography) and diffusion capacity (DLCO). Specialized tests like IOS or ABG analysis might be priced separately or as part of a more extensive package.
• Facility Type:
  • Government Hospitals: Often offer PFTs at highly subsidized rates or sometimes free for eligible patients. However, waiting times can be longer.
  • Standalone Diagnostic Centers: Typically offer competitive pricing and specialized PFT labs.
  • Private Multi-specialty Hospitals: Generally have higher costs due to advanced equipment, comprehensive services, and renowned specialists.
• Pulmonologist's Consultation Fee: If you are seeing a pulmonologist for a consultation and they then order PFTs, their consultation fee will be separate from the test cost. Some packages might include a follow-up interpretation.
• Equipment and Technology: Centers with state-of-the-art, calibrated PFT machines may charge more.
• Technician Charges: The expertise and training of the PFT technician contribute to the overall cost.
• Report Generation and Doctor's Interpretation: The fee often includes the generation of a detailed report and its interpretation by a qualified pulmonologist.
• Location: Major metropolitan cities generally have higher healthcare costs compared to tier-2 or tier-3 cities.

Recommendations for Patients:

• Compare Prices: It is advisable to call different diagnostic centers and hospitals in your area to inquire about their PFT costs and what is included in the price.
• Insurance Coverage: Check with your health insurance provider to see if PFTs are covered under your policy. Many policies do cover diagnostic tests when medically prescribed.
• Ask for a Detailed Breakup: Understand if the quoted price includes all components, such as the test itself, technician charges, report generation, and doctor's interpretation.
• Prescription: Always ensure you have a valid doctor's prescription for the PFT, as this is usually required for both scheduling and insurance claims.

By being informed about these cost variations and factors, patients in India can make more economical and suitable choices for their PFT needs.

How Ayu Helps

Ayu simplifies your healthcare journey by digitizing your medical records, including PFT results, making them easily accessible and securely shareable with your doctors for continuous, informed care.

FAQ

1. Is Pulmonary Function Test (PFT) painful? No, PFTs are not painful. They are non-invasive procedures. Some maneuvers, especially the forceful breathing during spirometry, require significant effort and might cause temporary dizziness or mild discomfort, but actual pain is not involved.

2. How long does a PFT take? The duration of a PFT session varies depending on the specific tests ordered. Basic spirometry might take 15-30 minutes, while a comprehensive PFT panel including lung volumes, diffusion capacity, and bronchodilator responsiveness can take anywhere from 45 to 90 minutes.

3. Can children undergo PFTs? Yes, children can undergo PFTs. However, specific techniques, child-friendly equipment, and highly trained technicians are often required, as younger children might struggle with the complex instructions for forced maneuvers. Alternative tests like Impulse Oscillation Testing (IOS) are excellent for children as they only require normal breathing.

4. What's the difference between spirometry and a full PFT? Spirometry is the most common and fundamental part of PFTs, measuring airflow and volume. A "full PFT" typically encompasses spirometry along with additional tests like lung volume measurements (e.g., using plethysmography) and diffusion capacity (DLCO) to provide a more complete assessment of lung function.

5. Do I need a referral from a doctor for PFT? Yes, generally you will need a referral or prescription from a physician (often a pulmonologist or general practitioner) to undergo PFTs. This ensures the test is medically indicated and the results can be interpreted within your clinical context.

6. How often should PFTs be done for chronic conditions? For chronic lung conditions like asthma or COPD, the frequency of PFTs depends on the stability and severity of the disease, as well as the treatment plan. Your doctor will advise on the appropriate schedule, which could range from annually to more frequently if symptoms worsen or treatment changes.

7. Can PFTs diagnose all lung diseases? No, PFTs are powerful diagnostic tools, but they are not the sole determinant for all lung diseases. They provide objective physiological data, which is then integrated with your medical history, physical examination findings, imaging studies (like chest X-rays or CT scans), and other laboratory tests to reach a comprehensive diagnosis. For example, PFTs can suggest interstitial lung disease, but a CT scan is often needed to confirm the diagnosis.

8. What if I can't perform the PFT maneuvers correctly? The PFT technician is highly trained to coach and guide you through the maneuvers. They will provide clear instructions and encouragement. If you are genuinely unable to perform the forced breathing maneuvers due to physical limitations or cognitive reasons, your doctor may consider alternative tests like Impulse Oscillation Testing (IOS) or other diagnostic approaches better suited to your condition.