1st order laboratory parameters – obligatory laboratory tests.
- Blood count
- Eosinophilia (increase in the number of eosinophilic granulocytes) [frequently expressed].
- Leukocytosis with left shift [may occur].
- Lymphopenia (decrease in lymphocytes).
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Muscle enzymes
- Creatine kinase (CK) [↑]
- Aldolase [↑]
- GOT [↑]
- Lactate dehydrogenase (LDH) [↑]
- Possibly detection of myoglobin in serum and urine.
- Immunological parameters
- ANF titer [negative]
- Antinuclear antibodies (ANAs) [detection is possible in approximately 50% of cases]
- Anti-Jo-1 (antibodies against histidyl transfer RNA synthetase) [detected in about 5% of cases]
- Anti-Mi2 [in 10% of cases]
- Anti-PmScl [in 10% of cases]
- U1-RNP [in 15% of cases]
- Anti-SRP [in approximately 5% of cases, often with cardiac involvement]
- Direct immunofluorescence (DIF) [frequently positive]
- Urine
- Proteinuria (increased excretion of protein in the urine) in the episode.
- Skin biopsy (tissue removal from the skin).
- Muscle biopsy – measurement of histological and biochemical properties; determined are pathological (disease-related) changes in the tissue.