Does my patient have asthma? Are they... Fit to fly? Fit to drive? What effect is their therapy having? COPD?

Why perform lung function testing?

  • It provides an objective means of evaluating the respiratory system (imagine managing hypertension without ever taking blood pressure measurements!)
  • Help with diagnosing the presence or absence of lung disease where there is a history of respiratory symptoms, physical indicators and abnormal laboratory findings.
  • Quantify the extent of respiratory changes in known diseases such as COPD, Asthma, Bronchiectasis, Interstitial disease, Neuromuscular disease, Autoimmune disease.
  • Measure effects of occupational or environmental exposure to dust and fumes.
  • Determine beneficial or negative effects of therapy such as respiratory medications, chemotherapy, radiotherapy or pulmonary rehabilitation.
  • Assess risk for surgical procedures such as lobectomy, pneumonectomy, upper abdominal procedures.

What's the difference between Lung Function Testing in General Practice and Lung Function Testing at the Tasmanian Lung Service(TLS)?

  • Peak Flow, COPD Screening (e.g. COPD-6, Piko-6) and Spirometry may often be called Lung Function Tests but are limited to measuring the airways.  Whilst many lung diseases affect this area, that is not the whole story. The TLS measures many additional aspects of the respiratory system (such as total lung size and diffusing capacity) so that we can supply you with the most complete picture available.
  • Our Respiratory Scientists and Technologists are trained specifically in lung function testing. The testing of lung function plus the research into respiratory disease is our entire focus.
  • Our equipment is excellent quality and calibrated regularly to be accurate.
  • We apply international guidelines to all our testing.
  • We understand what we are testing and work closely with patients to motivate them in achieving their best efforts.
  • Results are interpreted by Respiratory Physicians who bring their years of experience in providing meaningful and useful reports.

What lung function testing is appropriate?

This can depend on the amount of clinical and other information that you have already but we have grouped particular tests together as diseases or damage to the respiratory system tends to affect the following areas: the airways, the lung tissue, chest cavity and the pulmonary circulation. Respiratory disease can generally be characterised by patterns that take into account airway function (with or without reversibility), lung size and alveolar function. It may also depend on whether you have a known diagnosis or not.

  • Standard Test (Spirometry, Diffusing Capacity, Lung Volumes) - This is the "Catch Most" test and generally the most useful for diagnosis and monitoring of respiratory disease. It may be less helpful for diagnosing asthma as this disease is characterised by variable airway reversibility which may not be evident on the day of testing pre and post bronchodilator spirometry.
  • Exhaled Nitric Oxide and Spirometry – In people with atopic asthma, this test can be helpful to determine if airway function is impaired together with providing a marker of airway inflammation. It also a useful tool to determine the effect of, and titration of anti-inflammatory therapy (“Preventers”) in the control of known disease.
  • Respiratory Muscle Strength (MIPS/MEPS) – For people with neuromuscular disease or impairment, this test gives an indication of the degree of impairment to muscles of respiration.
  • Airwave Oscillometry – For children or adults who are unable to perform spirometry, this test provides an indication of airway function from tidal breathing only. It is highly sensitive to changes in the small airways and can be a useful tool looking for a bronchodilator response in people who have suspected or confirmed asthma.
  • Bronchial Challenge Test - On the occasions where a bronchodilator response has not been apparent with pre/post spirometry but asthma is still suspected, this test is appropriate. It is designed to challenge the airways with a “trigger” and determine if they are hyperresponsive. A positive test is consistent with the presence of asthma.
  • High Altitude Simulation Test - For people who have known respiratory disease, there is discomfort and a risk of adverse events from prolonged oxygen desaturation during domestic and international flights in commercial aircraft. This test is helpful to determine if supplemental oxygen is required during a flight, and the recommended amount.

Some examples for test selection – we are happy to answer any questions should you wish to call.

Example, 1
A person has symptoms of cough and breathlessness on exertion. They have a 20 pack year history of smoking. Possible diagnosis - Chronic Obstructive Pulmonary Disease (COPD)

Select “Standard Test” - This will help determine if the person has results consistent with COPD i.e. Narrowed/collapsed airways which are largely irreversible (No bronchodilator response). Diffusing capacity will give an indication of alveolar function and/or pulmonary vascular disease. Normal diffusing capacity can help determine if the person has predominant chronic bronchitis or with a component of emphysema. Large Total Lung Capacity with a higher than proportional Residual Volume gives an indication of Hyperinflation and Gas-trapping.

Example, 2
A person with Rheumatoid Arthritis has respiratory symptoms of breathlessness that has developed over the last 3 months, coinciding with the introduction of a new therapy. Possible diagnosis – Interstitial lung disease secondary to RA, or acute pneumonitis.

Select “Standard Test” - If established interstitial lung disease is present, there is likely to be a pattern of normal or supra-normal airway function, reduced diffusing capacity and lowered lung volumes. An acute episode of pneumonitis may be indicated by lowered diffusing capacity in the presence of normal airways and lung volumes.

Example, 3
A person has an established diagnosis of a mixed connective tissue disease and new treatment is being considered.

Select “Standard Test” - Baseline airway, diffusing capacity and lung volumes can be established which allow an excellent point of comparison should respiratory side-effects occur from treatment and re-testing be performed to monitor changes.

Example, 4
A person has intermittent symptoms of wheeze, sometimes associated with exertion. No history of smoking. Possible diagnosis of Asthma.

Select “Exhaled Nitric Oxide and spirometry”- Pre and Post bronchodilator spirometry give an indication of airway function and possible reversibility whilst NO results can indicate elevated levels of inflammation. If the previous test does not provide a clear picture i.e. airway function is normal/near normal without demonstrated reversibility and NO is normal then…

Select “Bronchial Challenge” - which provides a strong trigger for the airways that may demonstrate hyperresponsivess. i.e. Asthma

Example, 5
A person with known respiratory impairment wishes to visit family overseas but is concerned about being breathless in-flight.

Select “Altitude Simulation Test” - The available oxygen level in-flight at cruising altitude is replicated so that the patient response can be determined. If the O2 saturation drops below a threshold, additional O2 is given to maintain an adequate level and this is recommended for the upcoming flight.

Example, 6
A 5 year old child with cough and occasional wheeze is unable to successfully perform spirometry at the surgery with the practice nurse. Asthma is suspected.

Select “Airwave Oscillometry” - This gentle test requires only tidal breathing from the child and gives a measurement of airway function and any narrowing can be determined. When tested again after a bronchodilator, any changes can be measured to see if there is a reversible component consistent with asthma.

If you have concerns about your patients lung health, you can download a request form for your region below.