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Table 3 Diagnostic accuracy when basing endoscopy referral on varying SCD probability thresholds for the basic and the five faecal biomarker extended models, as observed in 810 Dutch patients with lower abdominal complaints referred for endoscopy in the CEDAR studya

From: Is there an added value of faecal calprotectin and haemoglobin in the diagnostic work-up for primary care patients suspected of significant colorectal disease? A cross-sectional diagnostic study

  Referred, % (95 % CI) SCD detected, n Missed SCDb, n Accuracy for SCD
Diagnostic model SCD probability threshold Total CRC IBD D AA Sensitivity, % (95 % CI) PPV, % (95 % CI) Specificity, % (95 % CI) NPV, % (95 % CI)
Basic
 ≥2.5 % 98.0 (96.4–99.2) 141 0 99.7 (96.7–100.0) 17.7 (15.2–20.5) 2.3 (1.0–4.1) 98.0 (76.5–100.0)
 ≥5.0 % 86.9 (83.9–89.6) 136 5 2 3 97.0 (92.6–98.8) 19.4 (16.6–22.5) 15.2 (12.1–18.8) 95.9 (90.2–98.5)
 ≥7.5 % 72.5 (69.1–75.6) 126 15 1 4 10 89.5 (83.2–93.8) 21.5 (18.3–25.0) 31.1 (27.5–35.0) 93.4 (89.2–96.1)
Calprotectin POC extended
 ≥2.5 % 97.9 (96.4–98.9) 141 0 100.0 (97.3–100.0) 17.8 (15.3–20.6) 2.6 (1.4–4.3) 100.0 (81.1–100.0)
 ≥5.0 % 83.6 (80.3–86.6) 138 3 1 2 97.4 (93.1–99.2) 20.3 (17.4–23.5) 19.3 (15.8–23.3) 97.2 (92.6–99.2)
 ≥7.5 % 68.5 (64.9–71.9) 125 16 1 1 5 9 88.1 (81.5–92.7) 22.4 (19.1–26.1) 35.6 (31.7–39.7) 93.4 (89.6–96.0)
Calprotectin ELISA extended
 ≥2.5 % 97.6 (96.0–98.8) 141 0 100.0 (97.3–100.0) 17.8 (15.3–20.7) 2.9 (1.5–4.8) 100.0 (82.7–100.0)
 ≥5.0 % 84.0 (81.1–86.6) 135 6 1 2 3 96.3 (91.5–98.7) 20.0 (17.1–23.2) 18.6 (15.5–22.0) 96.0 (90.7–98.6)
 ≥7.5 % 68.1 (64.7–71.4) 126 15 1 5 9 90.0 (83.7–94.2) 23.0 (19.7–26.7) 36.5 (32.8–40.4) 94.5 (91.0–96.8)
POC FIT extended
 ≥2.5 % 92.8 (89.0–96.2) 140 1 1 99.4 (96.2–100.0) 18.6 (16.0–21.6) 8.6 (4.5–13.1) 98.7 (91.2–99.9)
 ≥5.0 % 69.9 (64.4–75.3) 131 10 1 4 5 93.0 (87.4–96.4) 23.2 (19.6–27.1) 34.9 (28.7–41.4) 96.0 (92.6–97.9)
 ≥7.5 % 54.3 (49.6–59.1) 124 17 1 4 6 6 88.1 (81.4–92.8) 28.2 (24.0–32.9) 52.8 (47.4–58.1) 95.5 (92.7–97.2)
Calprotectin POC and POC FIT extended model
 ≥2.5 % 92.8 (89.4–95.7) 141 0 100.0 (97.3–100.0) 18.8 (16.1–21.8) 8.7 (5.2–12.8) 100.0 (93.4–100.0)
 ≥5.0 % 69.6 (64.7–74.3) 132 9 1 4 4 93.7 (88.2–96.8) 23.5 (19.9–27.3) 35.5 (29.9–41.2) 96.4 (93.1–98.2)
 ≥7.5 % 53.3 (48.7–57.8) 124 17 1 3 7 6 88.4 (81.7–93.1) 28.9 (24.7–33.5) 54.1 (49.1–59.1) 95.7 (93.1–97.4)
Calprotectin ELISA and POC FIT extended model
 ≥2.5 % 92.8 (89.5–95.6) 141 0 100.0 (97.3–100.0) 18.8 (16.1–21.8) 8.7 (5.3–12.7) 100.0 (93.5–100.0)
 ≥5.0 % 69.0 (64.8–73.0) 132 9 1 4 4 93.3 (87.7–96.7) 23.6 (20.2–27.3) 36.2 (31.6–40.9) 96.3 (93.0–98.1)
 ≥7.5 % 53.4 (49.2–57.6) 124 17 1 2 7 7 87.9 (81.0–92.7) 28.7 (24.4–33.3) 53.9 (49.2–58.5) 95.5 (92.7–97.3)
  1. AA advanced adenoma, CEDAR Cost-Effectiveness of a Decision rule for Abdominal complaints in primary caRe, CI confidence interval, CRC colorectal cancer, D diverticulitis, ELISA enzyme-linked immunosorbent assay, FIT faecal immunochemical test for haemoglobin, IBD inflammatory bowel disease, NPV negative predictive value, POC point-of-care, PPV positive predictive value, SCD significant colorectal disease
  2. aThe percentage referred and the accuracy measures are each averaged over the 10 imputed datasets. Hence, it is possible that, e.g. 100.0 % sensitivity does not directly match with 100.0 % NPV
  3. bA patient with SCD was considered missed if his/her predicted SCD probability was below the respective threshold for referral in at least 5 of the 10 imputed datasets