TableĀ 4

Sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of guaiac test for the identification of colorectal cancer

Sensitivity (95% CI)Specificity (95% CI)Accuracy (95% CI)PPV (95% CI)NPV (95% CI)
4+ FOB47% (32 to 62)91% (89 to 93)86% (82 to 93)41% (28 to 54)93% (91 to 95)
3+ FOB+ve79% (63 to 91)71% (69 to 73)72% (68 to 75)27% (21 to 30)96% (93 to 98)
2+FOB +ve88% (73 to 96)52% (50 to 53)57% (53 to 58)20% (16 to 21)97% (93 to 99)
1+ FOB+ve91% (76 to 98)31% (29 to 32)38% (35 to 40)15% (12 to 16)96% (90 to 99)
  • FOB, faecal occult blood.