1st order laboratory parameters – obligatory laboratory tests.
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate) [moderately to markedly elevated].
- Pathogen detection – succeeds in most cases already subsided infection rarely; detection from morning urine or stool.
- Detection of the HLA-B27 allele in the HLA-B gene (variant of the human protein complex Human Leukocyte Antigen-B (HLA-B); frequency: 70-80%).
Laboratory parameters 2nd order – depending on the results of the history, physical examination and the obligatory laboratory parameters – for differential diagnostic clarification.
- Urine status (rapid test for: nitrite, protein, hemoglobin, erythrocytes, leukocytes) incl. sediment, if necessary urine culture (pathogen detection and resistogram, that is, testing of suitable antibiotics for sensitivity/resistance).
- Antibodies (AK) against Chlamydia trachomatis; detection of Chlamydia trachomatis in the urethral swab (urethral swab).
- Rheumatoid factors (RF), antinuclear antibodies (ANA), cyclic citrulline peptide antibodies (CCP-Ak, anti-CCP, ACPA), Borrelia serology – to exclude other diseases from the rheumatic form circle.
