Table 2

Overall agreement between reviewers and agreement with consensus for each of the QUADAS items and for all items combined

QUADAS item

Agreement with consensus diagnosis (%) (95% confidence interval)

Reviewer variability (κ) (95% confidence interval)


1

2

3


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)*

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)


* Items for which review specific details were added to QUADAS

+The item relating to reference standard was not assessed for this review

Whiting et al. BMC Medical Research Methodology 2006 6:9   doi:10.1186/1471-2288-6-9

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