Eighteen studies reporting 28 datasets were included in the review. The prevalence of positive stool samples ranged from 6% to 53% (median 15%) across these 28 datasets.
There was significant between-study heterogeneity for all assays except TechLab Tox A/B Quik Chek (four studies) and BioMérieux VIDAS (one study).
The median (interquartile range) sensitivities of assays were: TechLab Tox A/B II 0.83 (0.82, 0.85; six studies, n=2,158); Meridian Premier 0.95 (0.86, 0.97; nine studies, n=2,891); TechLab Tox A/B Quik Chek 0.84 (0.81, 0.87; four studies, n=1,307); Remel Xpect 0.82 (0.75, 0.88; two studies, n=520), Meridian ImmunoCard 0.90 (0.87, 0.92; six studies, n=1,982); and BioMérieux VIDAS 0.76 (one study, n=62).
The median (interquartile range) specificities of assays were: TechLab Tox A/B II 0.99 (0.98,1.00; six studies, n=2,158); Meridian Premier 0.97 (0.95, 0.98; nine studies, n=2,891); TechLab Tox A/B Quik Chek 1.00 (0.99, 1.00; four studies, n=1,307); Remel Xpect 0.96 (0.95, 0.98; two studies, n=520); Meridian ImmunoCard 0.99 (0.98, 1.00; six studies, n=1,982); and BioMérieux VIDAS 0.93 (one study, n=62).
The reference method used did not affect sensitivity (p=0.45) or specificity (p=0.36).
There was no evidence for a significant difference in diagnostic odds ratios between any of the assays (p=0.33). Logistic regression suggested significant differences in sensitivity and specificity. Meridian Premier was most likely to give a positive result for true cases and TechLab Quik Chek was most likely to give a negative result for negative samples.