Tests may include the following: Serum glucose or glycosylated Hb (HbA1C) Antinuclear antibodies Hepatitis B and C serologic tests Serum and urine protein electrophoresis Cryoglobulins Rheumatoid factor Serologic test for syphilis (eg, rapid plasma reagin) HIV antibody test Complement levels (C3, C4) Test results may alter management and preclude the need for biopsy.