The advantages of the immunochemical test in detecting hidden blood in the stool

Abstract

The aim of the study: to compare new generation immunochemical test (FIT) with traditional guaiac test (FOB) in detection of fecal occult blood. A cohort of 300 patients referred for colonoscopy was examined by two different tests for FOB: quick test (CV) (FIT test for haemoglobin (Hb) and haemoglobin/haptoglobin (Hb/Hp) complex) and (quaiac test for Hb). Three fecal samples were tested and all subjects were examined by diagnostic colonoscopy with biopsy verification. The performance indicators (sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV) and area under the curve (AUC)) were calculated for both tests using three endpoints (adenoma (A), adenoma/ carcinoma (A/AC) and carcinoma (AC)). Colonoscopy (and biopsies) disclosed normal results in 114 (38.0 %) subjects, A in 91cases (30.3 %) and AC in 95 (31.7 %) patients. For the combined A + AC endpoint, the HS test had SE of 58.3 % and SP of 96.5 % (AUC = 0.774), while the CV test had 97.2 % SE and 85.8 % SP (AUC = 0.916) (p = 0.0001). For the A endpoint, the difference between HS and CV was even more significant, AUC = 0.637 and AUC = 0.898, respectively (p = 0.0001). For the AC endpoint, the HS test had SE of 85.3 % and SP of 96.5 % (AUC = 0.909), while the CV test had 100.0 % SE and 85.1 % SP (AUC = 0.925) (p = 0.0001). The ColonView test can be represented as a rapid test in the screening programme for colorectal cancer.