Table 1.

Validity of self-reported screening of each type according to recommendations: sensitivity, specificity, PPV, and NPV at baseline and follow-up

Sensitivity (95% CI)Specificity (95% CI)PPV (95% CI)NPV (95% CI)
Baseline (%)
    FOBT (n = 119)93.0 (75.1-99.6)89.7 (85.7-93.6)60.0 (42.6-75.9)98.9 (94.8-100.0)
    Flexible sigmoidoscopy (n = 118)86.9 (74.4-95.4)87.1 (81.4-92.4)72.5 (57.8-84.5)94.9 (88.4-98.4)
    Colonoscopy (n = 120)100.0 (85.6-100.0)86.6 (82.4-90.9)60.5 (45.8-74.0)100.0 (96.2-100.0)
    Barium enema (n = 120)73.5 (50.3-90.8)92.7 (89.5-96.0)55.0 (34.3-74.6)97.0 (92.3-99.3)
    Overall adherence (n = 120)*95.8 (88.7-99.4)80.6 (72.8-87.9)81.7 (71.6-89.5)95.9 (87.7-99.4)
Year 1 follow-up (%)
    FOBT (n = 119)77.3 (56.8-92.7)81.4 (77.8-85.6)40.5 (26.7-55.3)96.1 (90.1-99.1)
    Flexible sigmoidoscopy (n = 120)79.8 (67.2-90.0)81.1 (75.0-87.3)64.3 (49.5-77.5)91.0 (83.4-96.1)
    Colonoscopy (n = 118)91.8 (78.8-98.5)86.0 (80.8-91.2)66.7 (51.4-79.9)97.5 (92.2-100.0)
    Barium enema (n = 117)48.8 (27.6-71.4)90.3 (87.3-93.8)38.9 (19.6-61.0)93.9 (88.1-97.6)
    Overall adherence (n = 120)*93.9 (86.4-98.4)70.2 (62.0-78.5)76.3 (66.3-84.6)92.5 (81.7-98.1)
  • NOTE: Sensitivity (Se) and specificity (Sp) can then be computed by the following formulae: Se = (PPV × p) / [PPV × p + (1 − NPV)(1 − p)]; Sp = [NPV × (1 − p)] / [(1 − PPV) p + NPV (1 − p)].

    Abbreviation: 95% CI, 95% confidence interval.

  • * Overall screening adherence via any one of the four tests per recommendations.