Table 2 Proposed diagnostic criteria for hypersensitivity pneumonitis for clinical purposes

Terho [10]

1. exposure to offending antigens (revealed by history aerobiological or microbiological investigations of the environment, or measurements of antigen-specific IgG antibodies)

2. symptoms compatible with HP present and appearing or worsening some hours after antigen exposure;

3. lung infiltrations compatible with HP visible on chest X-ray

1. basal crepitant rales

2. impairment of the diffusing capacity

3. oxygen tension (or saturation) of the arterial blood either decreased at rest, or normal at rest but decreased during exercise

4. restrictive ventilation defect in the spirometry

5. histological changes compatible with HP

6. positive provocation test whether by work exposure or by controlled inhalation challenge

Richerson et al. [35]

1. the history and physical findings and pulmonary function tests indicate an interstitial lung disease

2. the X-ray film is consistent

3. there is exposure to a recognized cause

4. there is antibody to that antigen

Cormier et al. [36]

1. appropriate exposure

2. inspiratory crackles

3. lymphocytic alveolitis (if BAL is done)

4. dyspnea

5. infiltrates on chest radiographs or High Resolution Computed Tomography (HRCT)

1. recurrent febrile episodes

2. decreased Diffusing Capacity Test (DLCO)

3. precipitating antibodies to HP antigens

4. granulomas on lung biopsy (usually not required)

5. improvement with contact avoidance or appropriate treatment

Schuyler et al. [37]

1. symptoms compatible with HP

2. evidence of exposure to appropriate antigen by history or detection in serum and/or BAL fluid antibody

3. findings compatible with HP on chest radiograph or HRCT

4. BAL fluid lymphocytosis

5. pulmonary histologic changes compatible with HP

6. positive «natural challenge»

1. bibasilar rales

2. decreased DLCO

3. arterial hypoxemia, either at rest or during exercise