Table 2. PPV and NPV for the diagnosis of HCC of the AFP–BC (10 ng ml−1) and Δ6+AFP calculated for the training group (HCC prevalence 33%) and the validation group (HCC prevalence 25%), and for two tumour prevalences encountered in clinical practice.
|
Training group |
Validation group |
|||||||
|---|---|---|---|---|---|---|---|---|
| HCC prevalence (%) | PPV (95% CI) | NPV (95% CI) | Sens (95% CI) | Spec (95% CI) | PPV (95% CI) | NPV (95% CI) | Sens (95% CI) | Spec (95% CI) |
|
AFP-BC | ||||||||
| Study | 63.1 (56.6–69.1) | 82.7 (77.2–87.1) | 66.3 (59.8–72.1) | 80.6 (74.9–85.3) | 66.7 (58.3–74.2) | 88.9 (82.3–93.3) | 66.7 (58.3–74.2) | 88.9 (82.3–93.3) |
| 5 | 15.3 (11.1–20.6) | 97.8 (94.8–99.2) | 24 (16.3–33.8) | 98.1 (92.4–99.7) | ||||
| 3 | 9.6 (6.3–14.2) | 98.7 (96–99.7) | 15.7 (9.4–24.6) | 98.9 (93.5–99.9) | ||||
|
Δ6+ AFP | ||||||||
| Study | 53.5 (46.9–59.9) | 81.3 (75.4–85.9) | 67.5 (61.1–73.3) | 70.6 (64.4–76.2) | 43.5 (35.4–52.1) | 89 (82.5–93.4) | 75 (67–81.7) | 67.6 (59.2–75) |
| 5 | 10.8 (7.3–15.6) | 97.6 (94.6–99.1) | 10.9 (5.8–19.1) | 98.1 (92.4–99.7) | ||||
| 3 | 6.6 (4–10.8) | 98.6 (95.9–99.6) | 6.5 (2.8–13.8) | 98.9 (93.5–99.9) | ||||
|
CAI | ||||||||
| Study | 51.6 (45.1–58.1) | 86.2 (81–90.2) | 80 (74.3–84.8) | 62.5 (56–68.6) | 41.4 (33.4–49.9) | 90.5 (84.2–94.6) | 80.6 (73–86.5) | 62 (53.5–69.9) |
| 5 | 10.1 (6.7–14.8) | 98.3 (95.5–99.5) | 10 (5.2–18.1) | 98.4 (92.8–99.8) | ||||
| 3 | 6.2 (3.6–10.2) | 99 (96.5–99.8) | 6.2 (2.6–13.3) | 99 (93.8–100) | ||||
AFP-BC=alpha-fetoprotein best-cut-off at the time of HCC detection; Δ6+ AFP=increasing alpha-fetoprotein in the semester prior to HCC detection; CAI=combined Alpha-fetoprotein Index; HCC=hepatocellular carcinoma; PPV=positive predictive value; NPV=negative predictive value; Sens=sensibility; Spec=specificity; CI=confidence interval.