From the Guidelines
The diagnosis of sarcoidosis is based on a combination of clinical presentation, histological evidence of nonnecrotizing granulomatous inflammation, and exclusion of alternative causes of granulomatous disease.
Diagnostic Criteria
- Clinical presentation: a compatible clinical presentation is essential for the diagnosis of sarcoidosis 1
- Histological evidence: finding nonnecrotizing granulomatous inflammation in one or more tissue samples is a key diagnostic criterion 1
- Exclusion of alternative causes: excluding alternative causes of granulomatous disease is crucial for a definitive diagnosis of sarcoidosis 1
Diagnostic Tests
The American Thoracic Society clinical practice guideline recommends the use of various diagnostic tests, including imaging studies and tissue sampling, to support the diagnosis of sarcoidosis 1. However, the guideline also notes that the diagnosis of sarcoidosis is not standardized and is based on a combination of clinical, histological, and exclusionary criteria 1. Therefore, a multidisciplinary approach to diagnosis, involving clinicians from pulmonary, rheumatology, and other specialties, is recommended 1.
From the Research
Diagnostic Tests for Sarcoidosis
The diagnosis of sarcoidosis is a complex process that involves multiple steps and criteria. According to 2, 3, 4, 5, 6, there is no single diagnostic test that can confirm the disease. The following are some of the diagnostic tests and criteria used to diagnose sarcoidosis:
- Clinical presentation: A compatible clinical presentation is one of the major criteria for diagnosing sarcoidosis 3, 4, 6.
- Radiological presentation: A compatible radiological presentation, such as symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, is also a major criterion 3, 4, 6.
- Histological evidence: The histological evidence of non-necrotizing granulomatous inflammation in one or more tissues is a key criterion for diagnosing sarcoidosis 3, 4, 5, 6.
- Exclusion of alternative causes: The exclusion of alternative causes of granulomatous disease is also an essential criterion for diagnosing sarcoidosis 3, 4, 5, 6.
- Serum biomarkers: Certain serum biomarkers, such as sIL-2R, CRP, SAA, and chitotriosidase, may be useful in confirming sarcoidosis, while others, such as ACE, gammaglobulins, and lysozyme, may be more useful in discarding the diagnosis 2.
- Cytology: Cytology has been used effectively in demonstrating granulomas in various organs, and recent developments in cytodiagnosis have revolutionized this field 5.
Specific Diagnostic Criteria
Certain clinical features are considered to be highly specific of sarcoidosis and do not require histological confirmation, such as:
- Löfgren's syndrome
- Lupus pernio
- Heerfordt's syndrome New diagnostic guidelines have been published, and specific clinical criteria have been developed for the diagnosis of cardiac, neurological, and ocular sarcoidosis 6.