Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (830 page)

   Tubulointerstitial nephritis

   Dense deposit disease: C3 and factor B levels are low, and C4 is normal

   Goodpasture syndrome

Associated with miscellaneous conditions

   The antiphospholipid antibody syndrome

   Bacterial endocarditis

   Cryoglobulinemia (decreased C2 and C4)

   Acquired angioedema due to C1 inhibitor deficiency in B-cell lymphoproliferative diseases

   Alcoholic liver disease: low C3 and C4 due to decreased synthesis

   Acquired deficiency of decay accelerating factor (DAF) and CD59— complement regulatory proteins that normally inhibit complement activation—develops in PNH, resulting in accelerated red cell hemolysis

   Evans syndrome

Synovial Fluid

   Depressed CH50 is found in the synovial fluid of joints in

   Seronegative rheumatoid arthritis

   SLE