From the Guidelines
The workup for sarcoidosis should begin with a thorough history and physical examination, followed by chest radiography and pulmonary function tests, as recommended by the American Thoracic Society clinical practice guideline 1. The diagnosis of sarcoidosis requires a comprehensive approach, including laboratory tests such as complete blood count, comprehensive metabolic panel, serum calcium, 25-hydroxyvitamin D, angiotensin-converting enzyme (ACE) levels, and urinalysis.
- High-resolution computed tomography (HRCT) of the chest is essential for evaluating lung involvement.
- Definitive diagnosis typically requires tissue biopsy showing non-caseating granulomas, commonly obtained via bronchoscopy with transbronchial lung biopsy or mediastinal lymph node sampling. Additional testing should be guided by symptoms and may include:
- Cardiac MRI
- Electrocardiogram
- Ophthalmologic examination
- Neurological evaluation Pulmonary function tests should assess for restrictive or obstructive patterns, and the 6-minute walk test helps evaluate exercise capacity and oxygen desaturation, as noted in the European Respiratory Journal 1. The diagnosis is one of exclusion, requiring elimination of other granulomatous diseases such as tuberculosis, fungal infections, and malignancy before confirming sarcoidosis, and serum soluble interleukin-2 (sIL-2R), angiotensin converting enzyme (ACE) and lysozyme levels have become useful tools in the diagnosis of sarcoidosis and for evaluating disease activity 1.
From the Research
Sarcoidosis Workup
- The diagnosis of sarcoidosis relies on three criteria:
- a compatible clinical and radiologic presentation
- pathologic evidence of noncaseating granulomas
- exclusion of other diseases with similar findings, such as infections or malignancy 2
- A comprehensive diagnostic work-up and monitoring protocol is proposed, including a multidisciplinary approach, as sarcoidosis is a systemic disease 3
- The work-up should include:
- Chest radiography to identify bilateral hilar lymphadenopathy, the most typical sign of sarcoidosis 4
- Computed tomography (CT) to evidence diffuse pulmonary perilymphatic micronodules and to avoid confusion with differential diagnoses and comorbidities 4
- Pulmonary function tests, such as forced vital capacity, to reflect the impact of pulmonary sarcoidosis 4
- Cardiopulmonary exercise testing to understand the mechanism behind dyspnea of uncertain origin 4
- Endoscopic transbronchial needle aspiration and bronchoalveolar lavage (BAL) as additional tools to support diagnosis 4
- The diagnosis is not standardized, but certain clinical features are considered highly specific of the disease and do not require histological confirmation, such as Löfgren's syndrome, lupus pernio, and Heerfordt's syndrome 5
- New diagnostic guidelines have been published, including specific clinical criteria for the diagnosis of cardiac, neurological, and ocular sarcoidosis 5
- The probability of diagnosis at presentation is variable from case to case and may often be reinforced with time, and some investigations are mandatory at diagnosis to assess organ involvement and disease activity 4