Table 1:

Summary of investigations for a 56-year-old welder, with associated differential diagnosis

Investigations		Result	Possible differential diagnosis^*
Presentation	Pulmonary function test	Mild diffusion capacity impairment	Infection Interstitial lung disease Berylliosis Pneumoconiosis Sarcoidosis Malignancy
Presentation	Blood tests: complete blood count, coagulation, liver function, electrolytes, renal function and thyroid-stimulating hormone levels	All normal
5 months later	Chest radiograph	Nonspecific subsegmental atelectasis	Infection Interstitial lung disease Berylliosis Pneumoconiosis Sarcoidosis Malignancy
5 months later	Chest computed tomography	Pulmonary nodules with prominent lymph nodes
10 months later	Bronchoscopic biopsies of lung tissue and lymph nodes	Non-caseating granulomas Negative for mycobacteria, fungi, polarizable foreign material	Interstitial lung disease Berylliosis Sarcoidosis
1 year, 9 months later	Beryllium lymphocyte proliferation test	Positive (beryllium sensitized)	Berylliosis