Examination of synovial fluid from swollen and painful joints can contribute substantially to the diagnosis of joint diseases. After a skillful arthrocentesis the sample processing must follow swiftly, because the synovial fluid can not be effectively fixed due to its viscosity. The viscosity test and cellularity assessment with particular reference to the neutrophilic granulocyte fraction, as well as the examination of the native preparation in polarized light, are some specific steps in the processing of these samples. Diagnostic images include traumaticinfectiousand autoimmune arthritides, arthropaties associated with crystals and, least often, with tumors. Conclusion: The cytological examination of synovial fluid has its own pre-analytical and analytical characteristics. Respecting and supplementing them with nonmorphological examinations can significantly contribute to the successful treatment of pathological joint conditions.
Keywords: arthropathies associated with crystals; autoimmune arthritis; infectious arthritis; synovial fluid cytology; traumatic arthritis.