Spirometry & Respiratory Diagnosis in Primary Care

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How high-quality spirometry can improve respiratory diagnosis in primary care By Charlene Mhangami, Lead UK comPAS™ Clinical Specialist, Vitalograph High-quality spirometry gives you objective evidence to support earlier respiratory diagnosis, guide referral decisions and monitor lung function over time. This article looks at where spirometry adds the most value in primary care, what reliable testing requires, and how to build it into your everyday diagnostic pathway. Key Takeaways Reliable spirometry results depend on trained operators, the right device for the purpose, and testing to the ATS/ERS 2019 standard. Spirometry and FeNO provide complementary information - combining them, where available, reduces repeat appointments and delay. Wider access to quality-assured spirometry in primary care can support earlier diagnosis and reduce avoidable delay in treatment. Why spirometry is needed in primary care Primary care is often the first point of contact for people with respiratory symptoms. Objective tests such as spirometry and fractional exhaled nitric oxide (FeNO) — interpreted alongside clinical history and treatment response — can improve your diagnostic confidence. They also help you decide whether a condition can be managed in primary care or needs onward referral, reducing repeat appointments and delays to diagnosis. Symptoms alone cannot provide all the information needed for a respiratory diagnosis. Spirometry measures the volume and flow of air exhaled after a full inhalation. It can identify airflow obstruction or findings that may suggest a restrictive ventilatory defect. Access to high-quality spirometry in primary care can be limited by funding, staff training, service design and patient-related factors. As respiratory disease diagnoses rise, and mortality attributed to respiratory disease remains high, improving access to objective testing matters more than ever. Primary care providers are well placed to support early detection, diagnosis and long-term management of respiratory disease — helping to reduce mortality over time. Spirometry overview Spirometry commonly reports vital capacity (VC), forced expiratory volume in one second (FEV1), the FEV1/FVC ratio and peak expiratory flow (PEF). The clinical indication will determine which parameters are required for interpretation. Results are compared with reference values based on variables such as age, height and sex. Percentage-predicted values are used in some diagnostic criteria, while z-scores and lower limits of normal provide a more statistically appropriate way to identify results outside the expected range. Absolute values are also useful for tracking lung function over time, provided test quality and testing conditions are comparable. Important considerations for testing Reliable spirometry depends on obtaining technically acceptable and repeatable measurements. Competent operators and appropriate quality assurance are also key. The ATS/ERS 2019 technical statement provides the international benchmark for test performance. Reliable testing requires: • Suitable initial training, plus regular practice and refresher education to maintain competence • A device matched to the purpose of testing — handheld monitors may support case-finding or screening, while diagnostic spirometers must provide the accuracy, quality-control features and measurements needed for full assessment • Preparation and maintenance that follow the specific device's instructions and your local quality-assurance procedures, since these vary by technology and manufacturer Modern spirometers are available in handheld and PC-based formats, making testing easier to deliver in primary care. It's worth understanding the measurement technology behind each device, as this affects preparation, maintenance and quality assurance. Low-cost respiratory monitors typically use turbine-based technology, which is useful for screening, but not suitable for diagnostic spirometry. Diagnostic spirometers, by contrast, may use technologies such as Fleisch or ultrasonic flow measurement, designed for full assessment and greater precision. Respiratory monitors and screeners do not require calibration verification; diagnostic spirometers do, according to the ATS/ERS 2019 technical statement. Modern diagnostic spirometers are generally highly stable and seldom, if ever, need recalibration. However, calibration verification is important to confirm that the device is operating correctly and has not been damaged since it was last used. The rationale for testing should always determine the device used and the preparation required. Note: Patient safety is central to spirometry. Before testing, the operator should explain the effort required, check for relative contraindications in line with ATS/ERS guidance and consider whether forced respiratory manoeuvres could place the patient at unnecessary risk. If a contraindication is present, or if its clinical significance is uncertain, testing should be deferred until an appropriate clinical opinion has been obtained. Applying spirometry in primary care pathways Disease-specific guidance helps you decide when to use spirometry for diagnosis, monitoring and ongoing management. Relevant sources include GOLD guidance for COPD; the joint BTS, NICE and SIGN guidance for asthma; GINA guidance for asthma; and NICE guidance for idiopathic pulmonary fibrosis. In an asthma pathway, FeNO and spirometry provide complementary information: FeNO assesses type 2 airway inflammation, while spirometry evaluates expiratory airflow and may demonstrate variable airflow obstruction. Where both tests are indicated and locally available, coordinating them within the diagnostic pathway can reduce repeat visits and avoid unnecessary delay. Bronchodilator responsiveness should be assessed using the criteria in the current applicable guideline, rather than in isolation from the wider clinical picture. FeNO testing: FeNO measures type 2 airway inflammation. A raised result may support an asthma diagnosis when it is consistent with the patient's symptoms and clinical history. A normal or low result does not exclude asthma, particularly non-type 2 asthma. Baseline spirometry: Spirometry measures expiratory airflow and may identify abnormalities in lung mechanics such as airflow obstruction. Results should meet recognized quality standards and be interpreted alongside symptoms, clinical history and other objective findings. Bronchodilator responsiveness: Baseline spirometry is performed first. A bronchodilator, commonly salbutamol, is then administered and spirometry is repeated after the appropriate interval. The change in FEV1 should be assessed using the criteria in the relevant diagnostic guideline and interpreted within the wider clinical picture. Coordinated testing: Where FeNO and spirometry are both indicated and available, completing them within the same diagnostic pathway can reduce repeat appointments and unnecessary delay. The pathway should also define when abnormal, unclear or technically unacceptable results require repeat testing, further investigation or referral. Note: FeNO and spirometry provide complementary information rather than interchangeable results. FeNO assesses type 2 airway inflammation, while spirometry assesses lung function and variable obstruction. Optimizing spirometry in primary care Preventing exacerbations through monitoring People with respiratory conditions may experience exacerbations that affect their health and quality of life. Regular clinical review — including symptom assessment and appropriately timed objective testing — can help you identify deterioration and guide management. Full spirometry or selected measurements may support monitoring over time, but results should be considered alongside symptoms, treatment use and exacerbation history. Where software supports trending, comparable high-quality results can help you identify meaningful changes in lung function. Reducing diagnos