1st order laboratory parameters – obligatory laboratory tests.
- Small blood count
- Differential blood count [lymphocytosis (increase in the number of lymphocytes in the blood), eosinophilia (increase in the number of the number of eosinophilic granulocytes)]
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Liver parameters – alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), glutamate dehydrogenase (GLDH) and gamma-glutamyl transferase (gamma-GT, GGT), alkaline phosphatase, bilirubin.
- Biopsy (tissue sample) from the affected skin areas (in the advanced stages also biopsies from lymph nodes, bone marrow and the affected organs) [clonality detection: clonal atypical T-cell infiltrate with a CD4-positive immunophenotype with epidermotropism].
- Histological/immunohistological and molecular genetic examination.
- Class E immunoglobulins (IgE) [IgE↑]
- Flow cytometry (method of laboratory medicine used to analyze cells flowing individually at high speed past an electrical voltage or light beam) [marked T lymphocytosis (mainly CD4-positive cells) with increasing immaturity of lymphocytes]
Note: Only when the deeper layers of the skin are also affected, the disease is detectable for sure (T cells in the blood ↑).
