Additional tests include a complete blood count with differential, complete metabolic profile, thyroid function tests, serum protein electrophoresis, immunofixation electrophoresis, an autoimmune panel including ANA (antinuclear antibody), rheumatoid factor, anti-dsDNA, HIV testing, vitamin D level, sexually transmitted infection swabs, and if lymphadenopathy is present, lymph node biopsy. Here, BTG3 is linked to sexually transmitted disease.