Laboratory parameters of the 2nd order – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification
- Small blood count
- Differential blood count
- Inflammatory parameter – CRP (C-reactive protein)
- Rheumatism diagnostics – CRP (C-reactive protein) or BSG (blood sedimentation rate); rheumatoid factor (RF), CCP-AK (cyclic citrulline peptide antibodies), ANA (antinuclear antibodies); HLA-B27.
- Allergy tests – e.g., epicutaneous test (synonyms: patch test, patch test), prick test.
- Tear swab (microbiology) – for therapy-resistant conjunctivitis (conjunctivitis).