ITEM 19.  Report a cross tabulation of the results of the index tests (including indeterminate and missing results) by the results of the reference standard; for continuous results report the distribution of the test results by the results of the reference standard.

Example 1

Example 2 

Figure. Distribution on a log scale of the test results according to anti-CCP units for the different groups of patients.

A cutoff value set at 50 units guarantees a good specificity because all but seven of the non-RA patients have an antibody concentration below the threshold.[2] CTD:connective tissue disease; Oth. Rh. Dis: other rheumatoid diseases; NC:healthy controls.[2]

Scientists want to verify important results, and so re-analysis is an important aspect of the scientific method. To facilitate this process, authors should present results in the form of absolute numbers. Cross tabulations of test results in categories and graphs of distributions of continuous results are essential to allow scientific colleagues to (re)calculate measures of diagnostic accuracy or to perform alternative analyses, including meta-analysis. Authors should report all test results, including indeterminate test results on the index test and reference test.  

One example, with a few categories of test results, is taken from a study of fine-needle aspiration cytology in histologically proven thyroid carcinoma; the second example shows the distribution of the concentration of anti-citruline antibodies in patients with the target condition (rheumatoid arthritis) and in patients with several alternative diagnosis.

References