C3 and systemic lupus erythematosus: Otherimmunological criteria include: increased anti-Sm antibody levels; highantiphospholipid antibody levels (positive lupus anticoagulant test,false-positive rapid plasma reagin test, moderate to high anticardiolipinantibody levels, and positive anti-β2 glycoprotein I antibodytesting); decreased complement levels (C3, C4, CH50); and positive directCoombs test in the absence of hemolytic anemia.(29) Although autoantibodies are required in thediagnosis of SLE, their role in monitoring LN is unclear.