Table 2 Overall agreement between reviewers and agreement with consensus for each of the QUADAS items and for all items combined
From: Evaluation of QUADAS, a tool for the quality assessment of diagnostic accuracy studies
QUADAS item | Agreement with consensus diagnosis (%) (95% confidence interval) | Reviewer variability (κ) (95% confidence interval) | |||
|---|---|---|---|---|---|
| Â | Â | 1 | 2 | 3 | Â |
All items combined |  | 91 (88–94) | 90 (86–93) | 85 (81–89) | 0.66 (0.63 to 0.67) |
1 | Was the spectrum of patients representative of the patients who will receive the test in practice? (spectrum composition)* | 90 (73–98) | 87 (69–96) | 83 (65–94) | 0.73 (0.60 to 0.76) |
2 | Were selection criteria clearly described? (selection criteria) | 90 (73–98) | 83 (65–94) | 73 (54–88) | 0.55 (0.33 to 0.61) |
3 | Is the reference standard likely to correctly classify the target condition? (reference standard)* | Â | Â | Â | Â |
4 | Is the time period between reference standard and index test short enough to be reasonably sure that the target condition did not change between the two tests? (disease progression bias)* | 87 (69–96) | 90 (73–98) | 83 (65–94) | 0.68 (0.63 to 0.86) |
5 | Did the whole sample or a random selection of the sample, receive verification using a reference standard of diagnosis? (partial verification) | 87 (69–96) | 90 (73–98) | 93 (78–99) | 0.27(-0.06 to 0.39) |
6 | Did patients receive the same reference standard regardless of the index test result? (differential verification) | 97 (83–100) | 97 (83–100) | 97 (83–100) | 0.31 (-0.01 to 0.46) |
7 | Was the reference standard independent of the index test (i.e. the index test did not form part of the reference standard)? (incorporation bias) | 100 (88–100) | 100 (88–100) | 93 (78–99) | -0.02 (-0.03 to -0.01) |
8 | Was the execution of the index test described in sufficient detail to permit replication of the test? (index test execution) | 97 (83–100) | 100 (88–100) | 87 (69–96) | 0.60 (0.33 to 0.73) |
9 | Was the execution of the reference standard described in sufficient detail to permit its replication? (reference standard execution) | 93 (78–99) | 93 (78–99) | 93 (78–99) | 0.81 (0.60 to 0.87) |
10 | Were the index test results interpreted without knowledge of the results of the reference standard? (test review bias) | 90 (73–98) | 87 (69–96) | 97 (83–100) | 0.55 (-0.04 to 0.75) |
11 | Were the reference standard results interpreted without knowledge of the results of the index test? (reference standard review bias) | 93 (78–99) | 93 (78–99) | 93 (78–99) | 0.68 (0.46 to 0.76) |
12 | Were the same clinical data available when test results were interpreted as would be available when the test is used in practice? (clinical review bias)* | 90 (73–98) | 93 (78–99) | 50 (31–69) | 0.18 (-0.13 to 0.36) |
13 | Were uninterpretable/ intermediate test results reported? (uninterpretable test results) | 83 (65–94) | 70 (50–85) | 87 (69–96) | 0.32 (0.18 to 0.44) |
14 | Were withdrawals from the study explained? (withdrawals) | 90 (73–98) | 83 (65–94) | 80 (61–92) | 0.38 (0.33 to 0.51) |