Laboratory studies include chest roentgenogram, complete and differential blood cell counts, serum electrolytes, serum protein electrophoresis, erythrocyte sedimentation rate, tuberculin skin test (50), antinuclear antibody, C-reactive protein, venereal disease research laboratory test, serum antibody tests for herpes simplex virus I and II, herpes zoster virus, cytomegalovirus, rubella and measles and serological tests associated with syphilis, toxoplasmosis, systemic lupus erythematosus or rheumatoid arthritis. Here, CRP is linked to syphilis.