2nd order laboratory parameters – depending on the results of the history, physical examination, etc. – for differential diagnostic clarification
- Small blood count
- Differential blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Smear for bacteria / viruses
- Creatine kinase (CK) – if dermatomyositis (muscle inflammation with skin involvement) is suspected.
- Muscle biopsy – if dermatomyositis is suspected.
- Autoantibodies such as ANA (antinuclear antibodies) – if lupus erythematosus is suspected.
- Skin biopsy (tissue removal from the skin) – if sarcoidosis (Boeck’s disease) is suspected; see also under sarcoidosis (inflammatory multisystem disease, the cause of which is still unclear).