Table 2

Performance of faecal haemoglobin concentration (FHb) and faecal calprotectin concentration (FC) in the detection of colorectal cancer (CRC), higher-risk adenoma (HRA) and IBD using cut-offs at different concentrations (units: µg/g) (n=755)

FHb ≥10FC ≥50FHb detectableFHb detectable and/or FC ≥50FC ≥200FHb detectable and/or FC ≥200
Positivity rate23.5%62.0%58.3%80.5%25.9%66.0%
CRC (n=28)
 Number of cases282828282828
 True positives252328281328
 False negatives3500150
 False positives151427409573175464
 True negatives571271313146523254
 PPV14.2%5.1%6.4%4.7%6.9%5.7%
 NPV99.5%98.2%100%100%97.2%100%
 Sensitivity89.3%82.1%100%100%46.4%100%
 Specificity79.1%38.8%43.4%20.3%74.9%35.4%
HRA (n=41)
 Number of cases40*4140414140
 True positives20243338834
 False negatives201773336
 False positives156426404563180458
 True negatives554259306143505248
 PPV11.4%5.3%7.6%6.3%4.3%6.9%
 NPV96.5%93.8%97.8%97.9%93.8%97.6%
 Sensitivity50.0%58.5%82.5%92.7%19.5%85.0%
 Specificity78.0%37.8%43.1%20.3%73.7%35.1%
IBD (n=34)
 Number of cases34 32*34343234
 True positives252929332331
 False negatives935193
 False positives151421408568165461
 True negatives565273308145529251
 PPV14.2%6.4%6.7%5.5%12.2%6.3%
 NPV98.4%98.9%98.4%99.3%98.3%98.8%
 Sensitivity73.5%90.6%85.3%97.1%71.9%91.2%
 Specificity78.9%39.3%43.0%20.3%76.2%35.3%
CRC+HRA+IBD
 Number of cases102101*102103101102
 True positives707690994493
 False negatives3225124579
 False positives106374347502144399
 True negatives542251301142481245
 PPV39.8%16.9%20.6%16.5%23.4%18.9%
 NPV94.4%90.9%96.2%97.3%89.4%96.5%
 Sensitivity68.6%75.2%88.2%96.1%43.6%91.2%
 Specificity83.6%40.2%46.4%22.0%77.0%38.0%
  • *One case of HRA had FHb sample unsuitable for analysis. Two cases of IBD had FC samples unsuitable for analysis.

  • NPV, negative predictive value.