Serum C3 is persistently low in the following except:

Answer is A (Post streptococcal glomerulonephritis): Although all conditions mentioned in the question are associated with low compliment levels 'persistently depressed levels' are not seen in post streptococcal glomerulonephritis. In post streptococcal glomerulonephritis: serum C3 levels are depressed within 2 weeks, however these usually return to normal levels within 6 to 8 weeks Persistently depressed levels after this period should suggest another cause such as presence of C3 nephritic factor (Membranoproliferative glomenulonephritis) - Harrison Low complement levels (Immune complex glonerulonephritis) Idiopathic proliferative glomerulonephritis Crescentric glomenelonephritis Membranoproliferative glomerulonephritis Lupus nephritis Cryoglobulinemia Bacterial endocarditis Shunt nephritis Post infectious glomerulonephritis.(post streptococcal) Normal complement levels Anti GBM disease: Good posture's syndrome Pauci immune glomenulonephritis - Wegeners granulomatoses - Microscopic polyaeritis nodosa Immune complex mediated - IgA Nephropathy - Henoch schonlein purpura - Fibrillar)/ Glomerulonephritis