McNemar χ2test revisited: comparing sensitivity and specificity of diagnostic examinations
- 1 January 2008
- journal article
- research article
- Published by Taylor & Francis Ltd in Scandinavian Journal of Clinical and Laboratory Investigation
- Vol. 68 (1), 77-80
- https://doi.org/10.1080/00365510701666031
Abstract
When evaluating a novel diagnostic examination for clinical use, it should be compared with a reference standard, defined as the best available examination, which may include clinical and laboratory criteria. The novel examination and reference standard's results are usually presented in the form of a 2×2 table, which allows calculation of sensitivity, specificity and accuracy. It has been recommended that the measures of statistical uncertainty should be reported, such as the 95% confidence interval, when evaluating the accuracy of diagnostic examinations. Comparing the difference in sensitivity or specificity of a novel examination with the reference standard is important when evaluating its usefulness. The McNemar χ2 test, used to compare discordance of two dichotomous responses, can be applied for this purpose. However, applying the McNemar test to a 2×2 table for comparing the accuracy of examinations is not recommended, since this test is sensitive to the proportion of positive versus negative subjects. Moreover, if the novel examination has higher sensitivity than the one considered as the reference standard, constructing a classic 2×2 table would result in low specificity of the novel examination. Thus, in order to compare sensitivities and specificities between examinations, this table is inappropriate and an independent reference standard is necessary. In this article, we propose the use of the McNemar χ2 test to compare sensitivities between examinations using a 2×2 table exclusively among diseased patients, defined by a set of criteria and follow‐up of patients. Likewise, specificities can be compared applying the McNemar test among healthy individuals.Keywords
This publication has 14 references indexed in Scilit:
- Pleural fluid ADA, IgA‐ELISA and PCR sensitivities for the diagnosis of pleural tuberculosisScandinavian Journal of Clinical and Laboratory Investigation, 2007
- Clinical value of specific detection of immune complex-bound antibodies in pulmonary tuberculosisDiagnostic Microbiology and Infectious Disease, 2006
- The clinical applications and accuracy of 2 rapid near-patient tests in detecting Helicobacter pylori infectionDiagnostic Microbiology and Infectious Disease, 2006
- Biopsy vs. superficial scraping: detection of human papillomavirus 6, 11, 16, and 18 in potentially malignant and malignant oral lesionsJournal of Oral Pathology & Medicine, 2006
- Statistical Inference for ProportionsAmerican Journal of Roentgenology, 2005
- Immunoglobulin A (IgA) and IgG Immune Responses against P-90 Antigen for Diagnosis of Pulmonary Tuberculosis and Screening for Mycobacterium tuberculosis InfectionClinical and Vaccine Immunology, 2004
- Towards Complete and Accurate Reporting of Studies of Diagnostic Accuracy: The STARD InitiativeClinical Chemistry, 2003
- Pleural EffusionThe New England Journal of Medicine, 2002
- Evaluation of two ELISA's for detecting Chlamydia trachomatis from endocervical swabsDiagnostic Microbiology and Infectious Disease, 1992
- Simultaneous testing of McNemar's problem for several populationsPsychometrika, 1975