Seventeen studies (n=2,374) were included. Only three studies were considered to be of high methodological quality as they fulfilled at least 55% of the quality criteria. All studies included small numbers of patients. No studies were blinded. All studies failed to provide sufficient details on the included patients. Only three studies were reported to be prospective and consecutive, one was not and all other studies did not provide information on this. All studies avoided verification bias and provided sufficient information on the index test and reference standard.
Sensitivity ranged from 28% to 100%. Pooled sensitivity was 80% (95% CI 76% to 82%). There was strong evidence of heterogeneity (p=0.001, I2=89%).
Specificity ranged from 46% to 98%. Pooled specificity was 75% (95% CI 73% to 77%). There was strong evidence of heterogeneity (p=0.001, I2=96%).
Restriction of the analysis to the three studies judged to be of high methodological quality showed similar results.