Twenty studies (978 participants) were included in the review. Fourteen of 20 studies were prospective. Median QUADAS score was 10 (range 7 to 11).
D-lactate (four studies): The pooled estimate of sensitivity was 0.82 (95% CI 0.65 to 0.93) and the pooled estimate of specificity was 0.48 (95% CI 0.38 to 0.58). The pooled estimate of positive likelihood ratios was 3.04 (95% CI 0.73 to 12.59) and the pooled estimate of negative likelihood ratios was 0.35 (95% CI 0.18 to 0.70). There was significant between study heterogeneity for specificity and positive likelihood ratios.
i-FABP (three studies): The pooled estimate of sensitivity was 0.72 (95% CI 0.51 to 0.88) and the pooled estimate of specificity was 0.73 (95% CI 0.62 to 0.83). The pooled estimate of positive likelihood ratios was 2.44 (95% CI 0.41 to 14.58) and the pooled estimate of negative likelihood ratios was 0.51 (95% CI 0.29 to 0.91). There was significant between study heterogeneity for specificity and positive likelihood ratios.
GST (three studies): The pooled estimate of sensitivity was 0.68 (95% CI 0.54 to 0.80) and the pooled estimate of specificity was 0.85 (05% CI 0.76 to 0.92). The pooled estimate of positive likelihood ratios was 3.38 (95% CI 1.64 to 6.97) and the pooled estimate of negative likelihood ratios was 0.40 (95% CI 0.11 to 1.47). There was significant between study heterogeneity for sensitivity and negative likelihood ratios.
D-dimer (three studies): The pooled estimate of sensitivity was 0.89 (95% CI 0.77 to 0.96) and the pooled estimate of specificity was 0.40 (95% CI 0.33 to 0.47). The pooled estimate of positive likelihood ratios was 1.48 (95% CI 1.28 to 1.71) and the pooled estimate of negative likelihood ratios was 0.30 (95% CI 0.14 to 0.64). There was no significant between study heterogeneity for any measure.
Two studies were identified for each of the traditional laboratory markers of intestinal ischaemia (amylase, white blood count, pH, and base excess). The pooled sensitivity estimate for these markers ranged from 0.38 (95% CI 0.24 to 0.54) for pH to 0.80 (95% CI 0.66 to 0.91) for white blood count. Pooled specificity estimates ranged from 0.42 (95% CI 0.20 to 0.67) for base excess to 0.84 (95% CI 0.60 to 0.97) for pH.
Data for other markers were reported in the paper.
Data were insufficient to allow definitive comparison between traditional and novel markers of intestinal ischaemia.
Funnel plots showed no evidence of publication bias.