Reference Renal Disease Reference standards Immunoassay used Cut-off for +ve result
  Biopsy WHO GN types I-VI Proteinuria(P)/ Creatinine (C) RBC count/field    
Siegert  et al. [30] 13/88 biopsy P>0.5 g/24 h Increased C >10 Lab -made >137 U/ml
Siegert  et al. [31] 25/68 biopsy P>0.5 g/24 h RBCs in urine Lab-made >90 U/ml
Coremans  et al. [27] 17/33 biopsy P>0.5 g/24 h >5 Lab-made >90 U/ml
**Ravelli  et al. [57] 7/29 biopsy P>0.5 g/24 h Increased C >10 Lab-made >mean 95% OD above 59 HC controls
Norsworthy  et al. [29] 37/199 biopsy P>15 mg/ 24 h >10 Lab-made >20 U + 5 SD above controls
Trendelenberg  et al. [58] 14/48 biopsy Abnormal values of P >20 Lab-made > 80 U/ml
Loizou  et al. [59] 31/56 biopsy Abnormal P NR Lab-made >20 U + 5 SD above controls
Moroni  et al. [60] biopsy P>0.5 g/24 h >5 Lab-made > 80 U/ml
Oelzner  et al. [61] 27/79 biopsy P ≥ 0.5 g/24 h NR IMTEC ≥ 30 U/ml
Marto  et al. [62] 77/151 biopsy NR NR Diagenics >18 U/ml
Sinico  et al. [63] 40/61 biopsy P>2.0 g/24 h NR Lab-made >55 U/ml
Jaekell  et al. [64] Some biopsy P ≥ 0.5 g/24 h Increased C NR Orgentec >10 U/ml
**Kozyro  et al. [65] 12/112 biopsy P>1 g/L >20 Bühlmann >15 U/ml
Trendelenberg  et al. [66] 40/72 biopsy NR >20 Bühlmann >40 U/ml
Braun  et al. [67] 47/78 biopsy NR   INOVA >20 U/ml
Meyer  et al. [68] 55/70 biopsy P>0.5 g/dL/24 h Increased C Increased RBCs Bühlmann >32 U/ml
Smykal-Jankowiak  et al. [69] 37/48 Biopsy P ≥ 0.5g/24 h serum C Increased RBCs Bühlmann >32 U/ml
Fang  et al. [70] Biopsy P>0.3 g/24 h Increased C ≥ 5 Lab-made >mean OD + 2 SD above 63 controls
Tan  et al. [45] Biopsy NR NR Lab-made >mean OD + 2 SD above 100 controls
Cai  et al. [71] Biopsy P ≥ 0.5 g/24 h Increased RBCs IMTEC >20 U/ml
Mok  et al. [72] NR NR NR Euroimmun NR
Pradhan  et al. [73] Biopsy NR NR Binding Site >8 U/ml
Katsumata  et al. [33] 20/126 Biopsy P ≥ 0.5 g/24 h NR Bühlmann >40 U/ml
**Wu  et al. [74] 28/90 Biopsy P ≥ 50 mg/Kg/24 h Increased C NR Lab-made >mean OD + 1 SD  (40 U/ml) above controls
Zhang  et al. [75] 5/49 Biopsy P ≥ 0.5 g/24 h Increased RBCs Euroimmun ≥ 20U/ml
Pradhan  et al. [76] 45/60 Biopsy NR NR Autostat II C1q-CIC ≥ 50 μg/ml anti-C1q
Bernstein  et al. [26] 8/60 Biopsy P ≥ 0.5 g/24 h Increased C NR Lab-made >mean OD + 2 SD above 30 inactive SLE controls
Haseley  et al. [28] 75/240 Biopsy P ≥ 0.5 g/24 h Increased C >10 Lab-made >mean OD + 5 SD above 30 controls
Moura  et al. [77] No P ≥ 0.5 g/24 h Increased C NR INOVA >20 U/ml
De Moura  et al. [78] 15/62 Biopsy P ≥ 0.5 g/24 h serum C NR Diagenics ≥ 20 U/L
**Jesus  et al. [79] No P ≥ 0.5g/24 h Increased C >10 QUATA Lite >20 U/ml
** Pediatric study; OD: Optical Density; NR: Not Recorded
Table 2: Clinical assessment of nephritis and detection of anti-C1q antibodies in 31 studies.