scholarly journals Number Needed to Diagnose, Predict, or Misdiagnose: Useful Metrics for Non-Canonical Signs of Cognitive Status?

2018 ◽  
Vol 8 (3) ◽  
pp. 321-327 ◽  
Author(s):  
A.J. Larner
Keyword(s):  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Cognitive Status ◽  
Data Sets ◽  
Head Turning ◽  
Neurological Signs ◽  
Intuitive Appeal ◽  
Applause Sign ◽  
Single Exception ◽  
Accuracy Measures

Background/Aims: “Number needed to” metrics may hold more intuitive appeal for clinicians than standard diagnostic accuracy measures. The aim of this study was to calculate “number needed to diagnose” (NND), “number needed to predict” (NNP), and “number needed to misdiagnose” (NNM) for neurological signs of possible value in assessing cognitive status. Methods: Data sets from pragmatic diagnostic accuracy studies examining easily observed and dichotomised neurological signs (“attended alone” sign, “attended with” sign, head turning sign, applause sign, la maladie du petit papier) were analysed to calculate the NND, NNP, and NNM. Results: All measures of discrimination showed broad ranges. The range of NND and NNP suggested that these signs were, with a single exception, of value for correctly diagnosing or predicting cognitive status (presence or absence of cognitive impairment) when between 2 and 4 patients were examined. However, NNM showed similar values (range 1–5 patients) suggesting risk of misdiagnosis. Conclusion: NND, NNP, and NNM may be useful, intuitive, metrics in assessing the utility of diagnostic tests in day-to-day clinical practice. A ratio of NNM to either NND or NNP, termed the likelihood to diagnose or misdiagnose, may clarify the utility or inutility of diagnostic tests.

scholarly journals A software tool for calculating the uncertainty of diagnostic accuracy measures

2020 ◽  
Author(s):  
Theodora Chatzimichail ◽  
Aristides T. Hatjimihail
Keyword(s):  
Decision Making ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Clinical Decision Making ◽  
Single Point ◽  
Population Sample ◽  
Medical Decision ◽  
Interactive Program ◽  
Diagnostic Threshold ◽  
Accuracy Measures

Abstract Background: Screening and diagnostic tests are used to classify people with and without a disease. Although diagnostic accuracy measures are used to evaluate the correctness of a classification in clinical research and practice, there has been limited research on their uncertainty. The objective for this work is to develop a tool for calculating the uncertainty of diagnostic accuracy measures, as diagnostic accuracy is fundamental to clinical decision-making.Results: For this reason, a freely available interactive program has been developed in Wolfram Language. The program provides six modules with nine submodules, for calculating and plotting the standard and expanded uncertainty and the resultant confidence intervals of various diagnostic accuracy measures of screening or diagnostic tests, which measure a normally distributed measurand, applied at a single point in time in non-diseased and diseased populations. This is done for differing population sample sizes, mean and standard deviation of the measurand, diagnostic threshold and standard measurement uncertainty of the test.The application of the program is illustrated with a case study of glucose measurements in diabetic and non-diabetic populations, that demonstrates the calculation of the uncertainty of diagnostic accuracy measures.Conclusion: The presented interactive program is user-friendly and can be used as a flexible educational and research tool in medical decision making, to calculate and explore the uncertainty of diagnostic accuracy measures.

scholarly journals A Software Tool for Calculating the Uncertainty of Diagnostic Accuracy Measures

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 406
Author(s):  
Theodora Chatzimichail ◽  
Aristides T. Hatjimihail
Keyword(s):  
Decision Making ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Clinical Decision Making ◽  
Single Point ◽  
Medical Decision ◽  
Interactive Program ◽  
Diagnostic Uncertainty ◽  
Diagnostic Threshold ◽  
Accuracy Measures

Screening and diagnostic tests are applied for the classification of people into diseased and non-diseased populations. Although diagnostic accuracy measures are used to evaluate the correctness of classification in clinical research and practice, there has been limited research on their uncertainty. The objective for this work was to develop a tool for calculating the uncertainty of diagnostic accuracy measures, as diagnostic accuracy is fundamental to clinical decision-making. For this reason, the freely available interactive program Diagnostic Uncertainty has been developed in the Wolfram Language. The program provides six modules with nine submodules for calculating and plotting the standard combined, measurement and sampling uncertainty and the resultant confidence intervals of various diagnostic accuracy measures of screening or diagnostic tests, which measure a normally distributed measurand, applied at a single point in time to samples of non-diseased and diseased populations. This is done for differing sample sizes, mean and standard deviation of the measurand, diagnostic threshold and standard measurement uncertainty of the test. The application of the program is demonstrated with an illustrative example of glucose measurements in samples of diabetic and non-diabetic populations, that shows the calculation of the uncertainty of diagnostic accuracy measures. The presented interactive program is user-friendly and can be used as a flexible educational and research tool in medical decision-making, to calculate and explore the uncertainty of diagnostic accuracy measures.

scholarly journals Diagnostic Accuracy of the InBios Scrub Typhus Detect™ ELISA for the Detection of IgM Antibodies in Chittagong, Bangladesh

2018 ◽  
Vol 3 (3) ◽  
pp. 95 ◽  
Author(s):  
Stuart Blacksell ◽  
Hugh Kingston ◽  
Ampai Tanganuchitcharnchai ◽  
Meghna Phanichkrivalkosil ◽  
Mosharraf Hossain ◽  
...  
Keyword(s):  
General Population ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Scrub Typhus ◽  
Febrile Illness ◽  
High Sensitivity ◽  
Immunofluorescence Assay ◽  
Immunoglobulin M ◽  
Regional Assessment ◽  
Igm Elisa

Here we estimated the accuracy of the InBios Scrub Typhus Detect™ immunoglobulin M (IgM) ELISA to determine the optimal optical density (OD) cut-off values for the diagnosis of scrub typhus. Patients with undifferentiated febrile illness from Chittagong, Bangladesh, provided samples for reference testing using (i) qPCR using the Orientia spp. 47-kDa htra gene, (ii) IFA ≥1:3200 on admission, (iii) immunofluorescence assay (IFA) ≥1:3200 on admission or 4-fold rise to ≥3200, and (iv) combination of PCR and IFA positivity. For sero-epidemiological purposes (ELISA vs. IFA ≥1:3200 on admission or 4-fold rise to ≥3200), the OD cut-off for admission samples was ≥1.25, resulting in a sensitivity (Sn) of 91.5 (95% confidence interval (95% CI: 96.8–82.5) and a specificity (Sp) of 92.4 (95% CI: 95.0–89.0), while for convalescent samples the OD cut-off was ≥1.50 with Sn of 66.0 (95% CI: 78.5–51.7) and Sp of 96.0 (95% CI: 98.3–92.3). Comparisons against comparator reference tests (ELISA vs. all tests including PCR) indicated the most appropriate cut-off OD to be within the range of 0.75–1.25. For admission samples, the best Sn/Sp compromise was at 1.25 OD (Sn 91.5%, Sp 92.4%) and for convalescent samples at 0.75 OD (Sn 69.8%, Sp 89.5%). A relatively high (stringent) diagnostic cut-off value provides increased diagnostic accuracy with high sensitivity and specificity in the majority of cases, while lowering the cut-off runs the risk of false positivity. This study underlines the need for regional assessment of new diagnostic tests according to the level of endemicity of the disease given the high levels of residual or cross-reacting antibodies in the general population.

Translation: Beyond Diagnostic Accuracy: The Clinical Utility of Diagnostic Tests

2013 ◽  
Vol 3 (4) ◽  
pp. 269
Author(s):  
Patrick M.M. Bossuyt ◽  
Johannes B. Reitsma ◽  
Kristian Linnet ◽  
Karel G.M. Moons
Keyword(s):  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Clinical Utility

Diagnostic Tests and Diagnostic Accuracy in Surgery

2010 ◽  
pp. 83-98 ◽  
Author(s):  
Catherine M. Jones ◽  
Lord Ara Darzi ◽  
Thanos Athanasiou
Keyword(s):  
Diagnostic Accuracy ◽  
Diagnostic Tests

scholarly journals Five Reasons for the Failure to Diagnose Aldosterone Excess in Hypertension

2020 ◽  
Vol 52 (12) ◽  
pp. 827-833
Author(s):  
George P. Piaditis ◽  
Gregory Kaltsas ◽  
Athina Markou ◽  
George P. Chrousos
Keyword(s):  
Essential Hypertension ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Performance Characteristics ◽  
Primary Hyperaldosteronism ◽  
Present Review ◽  
Clinical Implications

AbstractPrimary hyperaldosteronism (PA) is a well-known cause of hypertension although its exact prevalence amongst patients with apparent essential hypertension has been a matter of debate. A number of recent studies have suggested that mild forms of PA may be relatively common taking into consideration factors that were previously either overestimated or ignored when developing diagnostic tests of PA and when applying these tests into normotensive individuals. The performance characteristics and diagnostic accuracy of such tests are substantially increased when the adrenocorticotrophin effect, inappropriate potassium levels and their application in carefully selected normotensive individuals are considered. In the present review, we critically analyze these issues and provide evidence that several, particularly mild, forms of PA can be effectively identified exhibiting potentially important clinical implications.

scholarly journals A Systematic Review and Meta-analysis of the Diagnostic Accuracy of Nucleic Acid Amplification Tests for Tuberculous Meningitis

2019 ◽  
Vol 57 (6) ◽  
Author(s):  
Ali Pormohammad ◽  
Mohammad Javad Nasiri ◽  
Timothy D. McHugh ◽  
Seyed Mohammad Riahi ◽  
Nathan C. Bahr
Keyword(s):  
Systematic Review ◽  
Nucleic Acid ◽  
Diagnostic Accuracy ◽  
Likelihood Ratio ◽  
Tuberculous Meningitis ◽  
Meta Analysis ◽  
Nucleic Acid Amplification ◽  
Data Sets ◽  
Reference Standard ◽  
Sensitivity Specificity

ABSTRACTThe diagnosis of tuberculous meningitis (TBM) is difficult and poses a significant challenge to physicians worldwide. Recently, nucleic acid amplification (NAA) tests have shown promise for the diagnosis of TBM, although their performance has been variable. We undertook a systematic review and meta-analysis to evaluate the diagnostic accuracy of NAA tests with cerebrospinal fluid (CSF) samples against that of culture as the reference standard or a combined reference standard (CRS) for TBM. We searched the Embase, PubMed, Web of Science, and Cochrane Library databases for the relevant records. The QUADAS-2 tool was used to assess the quality of the studies. Diagnostic accuracy measures (i.e., sensitivity and specificity) were pooled with a random-effects model. All statistical analyses were performed with STATA (version 14 IC; Stata Corporation, College Station, TX, USA), Meta-DiSc (version 1.4 for Windows; Cochrane Colloquium, Barcelona, Spain), and RevMan (version 5.3; The Nordic Cochrane Centre, the Cochrane Collaboration, Copenhagen, Denmark) software. Sixty-three studies comprising 1,381 cases of confirmed TBM and 5,712 non-TBM controls were included in the final analysis. These 63 studies were divided into two groups comprising 71 data sets (43 in-house tests and 28 commercial tests) that used culture as the reference standard and 24 data sets (21 in-house tests and 3 commercial tests) that used a CRS. Studies which used a culture reference standard had better pooled summary estimates than studies which used CRS. The overall pooled estimates of sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) of the NAA tests against culture were 82% (95% confidence interval [CI], 75 to 87%), 99% (95% CI, 98 to 99%), 58.6 (95% CI, 35.3 to 97.3), and 0.19 (95% CI, 0.14 to 0.25), respectively. The pooled sensitivity, specificity, PLR, and NLR of NAA tests against CRS were 68% (95% CI, 41 to 87%), 98% (95% CI, 95 to 99%), 36.5 (95% CI, 15.6 to 85.3), and 0.32 (95% CI, 0.15 to 0.70), respectively. The analysis has demonstrated that the diagnostic accuracy of NAA tests is currently insufficient for them to replace culture as a lone diagnostic test. NAA tests may be used in combination with culture due to the advantage of time to result and in scenarios where culture tests are not feasible. Further work to improve NAA tests would benefit from the availability of standardized reference standards and improvements to the methodology.

scholarly journals A Prospective Hospital Study to Evaluate the Diagnostic Accuracy of Rapid Diagnostic Tests for the Early Detection of Leptospirosis in Laos

2018 ◽  
Vol 98 (4) ◽  
pp. 1056-1060 ◽  
Author(s):  
Sabine Dittrich ◽  
Latsaniphone Boutthasavong ◽  
Dala Keokhamhoung ◽  
Weerawat Phuklia ◽  
Scott B. Craig ◽  
...  
Keyword(s):  
Early Detection ◽  
Diagnostic Accuracy ◽  
Diagnostic Tests ◽  
Rapid Diagnostic Tests ◽  
Hospital Study
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