Diagnostic performance of different fecal calprotectin assays to support the diagnosis of SpA.
| Quantum Blue Calprotectin | LIAISON Calprotectin | QUANTA Lite Calprotectin Extended Range | |||
|---|---|---|---|---|---|
| AUC (95% CI) | 0.658 (0.556–0.750) | 0.684 (0.583–0.774), p = 0.2964* | 0.661 (0.559–0.754), p = 0.9056* | ||
| Median (95% CI) in SpA (n = 52) | 59.0 µg/g (39.9–82.0) | 25.4 µg/g (15.8–38.7) | 24.6 µg/g (15.2–32.6) | ||
| Median (95% CI) in non-SpA (n = 47) | 32 µg/g (15.0–45.4), p = 0.0056§ | 11.5 µg/g (7.9–16.6), p = 0.0017§ | 13.0 µg/g (10.9–15.6) p = 0.0057§ | ||
| Manufacturer’s cutoff | 50 µg/g | 200 µg/g | 50 µg/g | 50 µg/g | 120 µg/g |
| Sensitivity for SpA (95% CI) | 56% (41–70) | 6% (1–16) | 29% (17–43) | 15% (7–28) | 0% (0–7) |
| Specificity for SpA (95% CI) | 68% (53–81) | 98% (89–100) | 94% (83–99), p < 0.0001** | 96% (86–100), p < 0.0001** | 98% (89–100) |
| Cutoff at 98% specificity for SpA | 157 µg/g | 62 µg/g | 60 µg/g | ||
| Sensitivity for SpA (95% CI) | 13% (6–26) | 21% (11–35) | 8% (2–19) | ||
| Likelihood ratio for SpA (95% CI) | 6.3 (0.8–49.5) | 9.9 (1.3–74.1) | 3.6 (0.4–31.2) | ||
| OR for SpA (95% CI) | 7.2 (0.8–60.5), p = 0.1308§§ | 12.3 (1.5–99.8), p = 0.018§§ | 3.8 (0.4–35.6), p = 0.2372§§ | ||
↵* Evaluation performed versus AUC Quantum Blue Calprotectin using the method of DeLong, et al, in MEDCALC software (version 17.1).
↵§ Mann-Whitney U test (independent samples).
↵** McNemar test (paired proportions) versus Quantum Blue Calprotectin.
↵§§ OR calculated using the method of Altman, et al, in MEDCALC: if the associated p value is < 0.05 it can be concluded that the OR is significantly different from 1 and that the odds in 1 group are significantly higher than in the other. SpA: spondyloarthropathies; AUC: area under the curve.