2nd order laboratory parameters – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.
- Small blood count
- Differential blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Urine status (including protein detection) – if vasculitic (“caused by vascular inflammation”) nodules are suspected.
- Uric acid – if gouty tophi (gouty nodules) is suspected.
- Infectious serology
- Total cholesterol, HDL cholesterol, LDL cholesterol; triglycerides – eruptive xanthomas (small yellowish-white skin lesions).
- Rheumatism diagnostics – CRP (C-reactive protein) or ESR (blood sedimentation rate); rheumatoid factor (RF), CCP-AK (cyclic citrulline peptide antibodies), ANA (antinuclear antibodies) – if rheumatoid arthritis is suspected (subcutaneous rheumatoid nodules).
- Skin biopsy (tissue sampling from the skin).