Which initial investigations should be performed for a patient suspected of having interstitial lung disease?

For a patient suspected of having interstitial lung disease (ILD), the initial investigations should include:

• Detailed clinical history and examination to identify clinical features and exclude alternative diagnoses such as environmental exposures, connective tissue diseases, or drug-induced lung disease.
• Blood tests to help exclude alternative diagnoses and associated conditions.
• Lung function tests, including spirometry and gas transfer (diffusing capacity for carbon monoxide), to assess lung impairment.
• Chest X-ray as a baseline imaging to identify abnormalities and exclude other pathologies.
• High-resolution computed tomography (HRCT) of the thorax to provide detailed imaging necessary for diagnosis and assessment of ILD.

These investigations form the basis for multidisciplinary team assessment and further diagnostic steps if a confident diagnosis cannot be made from these initial tests alone.

References: NICE CG163