As many as 62 per cent of patients identified as depressed by two-item screening tests will actually not be.
Meta-analysis of 22 trials of ultra-short tests found two and three-item tests for depression had a positive predictive value of only 38 per cent. The sensitivity of the tests was 74 per cent and specificity 75 per cent.
The study concluded two-item questionnaires should only be used ‘where there are sufficient resources for second stage assessment of those who screen positive'.
Two-item questionnaires are also recommended by NICE.