scholarly journals Viewpoint: Diagnosis in primary care: probabilistic reasoning

2012 ◽  
Vol 4 (2) ◽  
pp. 166 ◽  
Author(s):  
Bruce Arroll ◽  
GM Allan ◽  
C Raina Elley ◽  
Tim Kenealy ◽  
James McCormack ◽  
...  
Keyword(s):  
Primary Care ◽  
Diagnostic Accuracy ◽  
False Positive ◽  
Probabilistic Reasoning ◽  
False Negative ◽  
Post Test ◽  
Low Prevalence ◽  
Post Test Probability ◽  
Test Probability ◽  
Rule Out

This article develops the concept of probabilistic reasoning as one of the techniques clinicians use in making a diagnosis. We develop the concept that every question and every examination is a diagnostic test ultimately leading to a rule in or rule out of a diagnosis. We also develop the concept of pre-test probability pointing out that false positive tests are an issue in low-prevalence settings and false negative tests are a problem. Investigative tests work best in medium-prevalence settings. The purpose of taking a history and conducting an examination is to increase the pre-test probability to a point where either treatment is commenced or more expensive/time-consuming/dangerous tests are indicated. Pre-test probabilities on their own can be used to rule out conditions. We also show how pre-test probabilities relate to the Fagan nomogram which enables visualisation of large changes in post-test probabilities which can lead to treatment/further investigation. KEYWORDS: Likelihood ratio; pre-test and post-test probability; diagnostic accuracy; probabilistic reasoning

scholarly journals Impact of a decreasing pre-test probability on the performance of diagnostic tests for coronary artery disease

2019 ◽  
Vol 20 (11) ◽  
pp. 1198-1207 ◽  
Author(s):  
Luis Eduardo Juarez-Orozco ◽  
Antti Saraste ◽  
Davide Capodanno ◽  
Eva Prescott ◽  
Haitham Ballo ◽  
...  
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
False Positive ◽  
Diagnostic Technique ◽  
Non Invasive ◽  
Selection Tool ◽  
Post Test ◽  
Artery Disease ◽  
Post Test Probability ◽  
Test Probability

Abstract Aims To provide a pooled estimation of contemporary pre-test probabilities (PTPs) of significant coronary artery disease (CAD) across clinical patient categories, re-evaluate the utility of the application of diagnostic techniques according to such estimates, and propose a comprehensive diagnostic technique selection tool for suspected CAD. Methods and results Estimates of significant CAD prevalence across sex, age, and type of chest pain categories from three large-scale studies were pooled (n = 15 815). The updated PTPs and diagnostic performance profiles of exercise electrocardiogram, invasive coronary angiography, coronary computed tomography angiography (CCTA), positron emission tomography (PET), stress cardiac magnetic resonance (CMR), and SPECT were integrated to define the PTP ranges in which ruling-out CAD is possible with a post-test probability of <10% and <5%. These ranges were then integrated in a new colour-coded tabular diagnostic technique selection tool. The Bayesian relationship between PTP and the rate of diagnostic false positives was explored to complement the characterization of their utility. Pooled CAD prevalence was 14.9% (range = 1–52), clearly lower than that used in current clinical guidelines. Ruling-out capabilities of non-invasive imaging were good overall. The greatest ruling-out capacity (i.e. post-test probability <5%) was documented by CCTA, PET, and stress CMR. With decreasing PTP, the fraction of false positive findings rapidly increased, although a lower CAD prevalence partially cancels out such effect. Conclusion The contemporary PTP of significant CAD across symptomatic patient categories is substantially lower than currently assumed. With a low prevalence of the disease, non-invasive testing can rarely rule-in the disease and focus should shift to ruling-out obstructive CAD. The large proportion of false positive findings must be taken into account when patients with low PTP are investigated.

The diagnostic accuracy of wrist cineradiography in diagnosing scapholunate dissociation

2013 ◽  
Vol 39 (3) ◽  
pp. 263-271 ◽  
Author(s):  
G. S. I. Sulkers ◽  
N. W. L. Schep ◽  
M. Maas ◽  
C. M. A. M. van der Horst ◽  
J. C. Goslings ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Predictive Value ◽  
Diagnostic Value ◽  
Inclusion Criteria ◽  
Scapholunate Ligament ◽  
Scapholunate Dissociation ◽  
Post Test ◽  
Sensitivity Specificity ◽  
Post Test Probability ◽  
Test Probability

Ruptures of the scapholunate ligament (SLL) may cause carpal instability, also known as scapholunate dissociation (SLD). SLD may lead to osteoarthritis of the radiocarpal and midcarpal joints. The aim of this retrospective study was to determine the diagnostic value of wrist cineradiography in detecting SLD. All cineradiographic studies made during a 24 year period were retrieved. All patients who underwent the confirmation method (arthroscopy and/or arthrotomy) and cineradiography were included. In total, 84 patients met the inclusion criteria. Sensitivity, specificity, likelihood ratio, positive predictive value, negative predictive value, and diagnostic accuracy for detecting SLD were calculated for radiography and cineradiography. Cineradiography had a sensitivity of 90%, a specificity of 97%, and a diagnostic accuracy of 0.93 in detecting SLD. Radiography had a sensitivity of 81%, a specificity of 80%, and a diagnostic accuracy of 0.81. Cineradiography has a high diagnostic value for diagnosing SLDs. A positive cineradiography markedly increases the post-test probability of SLD.

Diagnostic accuracy of three clinical dehydration scales: a systematic review

2017 ◽  
Vol 103 (4) ◽  
pp. 383-388 ◽  
Author(s):  
Anna Falszewska ◽  
Hania Szajewska ◽  
Piotr Dziechciarz
Keyword(s):  
Diagnostic Accuracy ◽  
Low Income ◽  
Positive Likelihood Ratio ◽  
High Income ◽  
Low Income Countries ◽  
Severe Dehydration ◽  
Post Test ◽  
Sensitivity Specificity ◽  
Post Test Probability ◽  
Test Probability

ObjectiveTo systematically assess the diagnostic accuracy of the Clinical Dehydration Scale (CDS), the WHO Scale and the Gorelick Scale in identifying dehydration in children with acute gastroenteritis (AGE).DesignThree databases, two registers of clinical trials and the reference lists from identified articles were searched for diagnostic accuracy studies in children with AGE. The index tests were the CDS, WHO Scale and Gorelick Scale, and reference standard was the percentage loss of body weight. The main analysed outcomes were the sensitivity, specificity, positive likelihood ratio (LR) and negative LR.ResultsTen studies were included. In high-income countries, the CDS provided a moderate-to-large increase in the post-test probability of predicting moderate to severe (≥6%) dehydration (positive LR 3.9–11.79), but it was of limited value for ruling it out (negative LR 0.55–0.71). In low-income countries, the CDS showed limited value both for ruling in and ruling out moderate-to-severe dehydration. In both settings, the CDS showed poor diagnostic accuracy for ruling in or out no dehydration (<3%) or some dehydration (3%–6%). The WHO Scale showed no or limited value in assessing dehydration in children with diarrhoea. With one exception, the included studies did not confirm the diagnostic accuracy of the Gorelick Scale.ConclusionLimited evidence suggests that the CDS can help in ruling in moderate-to-severe dehydration (≥6%) in high-income settings only. The WHO and Gorelick Scales are not helpful for assessing dehydration in children with AGE.

scholarly journals Component-Resolved Diagnosis of Hazelnut Allergy in Children

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 640
Author(s):  
Carlo Caffarelli ◽  
Carla Mastrorilli ◽  
Angelica Santoro ◽  
Massimo Criscione ◽  
Michela Procaccianti
Keyword(s):  
Diagnostic Accuracy ◽  
Area Under The Curve ◽  
Food Challenge ◽  
Final Diagnosis ◽  
Childhood And Adolescence ◽  
Test Results ◽  
Post Test ◽  
Food Challenges ◽  
Post Test Probability ◽  
Test Probability

Hazelnuts commonly elicit allergic reactions starting from childhood and adolescence, with a rare resolution over time. The definite diagnosis of a hazelnut allergy relies on an oral food challenge. The role of component resolved diagnostics in reducing the need for oral food challenges in the diagnosis of hazelnut allergies is still debated. Therefore, three electronic databases were systematically searched for studies on the diagnostic accuracy of specific-IgE (sIgE) on hazelnut proteins for identifying children with a hazelnut allergy. Studies regarding IgE testing on at least one hazelnut allergen component in children whose final diagnosis was determined by oral food challenges or a suggestive history of serious symptoms due to a hazelnut allergy were included. Study quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Eight studies enrolling 757 children, were identified. Overall, sensitivity, specificity, area under the curve and diagnostic odd ratio of Cor a 1 sIgE were lower than those of Cor a 9 and Cor a 14 sIge. When the test results were positive, the post-test probability of a hazelnut allergy was 34% for Cor a 1 sIgE, 60% for Cor a9 sIgE and 73% for Cor a 14 sIgE. When the test results were negative, the post-test probability of a hazelnut allergy was 55% for Cor a 1 sIgE, 16% for Cor a9 sIgE and 14% for Cor a 14 sIgE. Measurement of IgE levels to Cor a 9 and Cor a 14 might have the potential to improve specificity in detecting clinically tolerant children among hazelnut-sensitized ones, reducing the need to perform oral food challenges.

scholarly journals “Clinician’s Probability Calculator” to Convert Pre-Test to Post-Test Probability of COVID-19, Based on Method Validation from Each Laboratory

2021 ◽  
Author(s):  
Zoe Brooks ◽  
Saswati Das ◽  
Tom Pliura
Keyword(s):  
Test Performance ◽  
False Negative ◽  
Likelihood Ratios ◽  
Unique Challenge ◽  
Molecular Tests ◽  
Percent Agreement ◽  
Post Test ◽  
Test Result ◽  
Post Test Probability ◽  
Test Probability

Identifying the SARS-CoV-2 virus has been a unique challenge for the scientific community. In this paper, we discuss a practical solution to help guide clinicians with interpretation of the probability that a positive, or negative, COVID-19 test result indicates an infected person, based on their clinical estimate of pre-test probability of infection.The authors conducted a small survey on LinkedIn to confirm that hypothesis that that the clinical pre-test probability of COVID-19 increases relative to local prevalence of disease plus patient age, known contact, and severity of symptoms. We examined results of PPA (Positive Percent Agreement, sensitivity) and NPA (Negative Percent Agreement, specificity) from 73 individual laboratory experiments for molecular tests for SARS-CoV-2 as reported to the FIND database 1, and for selected methods in FDA EUA submissions2,3. Authors calculated likelihood ratios to convert pre-test to post-test probability of disease and designed an online calculator to create graphics and text to report results. Despite best efforts, false positive and false negative Covid-19 test results are unavoidable4,5. A positive or negative test result from one laboratory has a different probability for the presence of disease than the same result from another laboratory. Likelihood ratios and confidence intervals can convert the physician or other healthcare professional&rsquo;s clinical estimate of pre-test probability to post-test probability of disease. Ranges of probabilities differ depending on proven method PPA and NPA in each laboratory. We recommend that laboratories verify PPA and NPA and utilize a the &ldquo;Clinician&rsquo;s Probability Calculator&rdquo; to verify acceptable test performance and create reports to help guide clinicians with estimation of post-test probability of COVID-19.

Performance of the 2016 diagnostic criteria for fibromyalgia in a tertiary care pain rehabilitation setting: a diagnostic accuracy study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Karin Due Bruun ◽  
Hanne Irene Jensen ◽  
Morten Rune Blichfeldt-Eckhardt ◽  
Henrik Bjarke Vaegter ◽  
Palle Toft ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Diagnostic Criteria ◽  
Tertiary Care ◽  
Survey Questionnaire ◽  
Diagnostic Accuracy Study ◽  
Rehabilitation Centers ◽  
Post Test ◽  
Accuracy Study ◽  
Post Test Probability ◽  
Test Probability

Abstract Objectives With the International Classification of Diseases 11th revision (classifying fibromyalgia as a primary pain disorder) soon to be implemented, the importance of pain physicians being able to identify patients with fibromyalgia is emphasized. The diagnostic criteria proposed in 2016 are based on self-reported pain distribution and symptom severity. The study aimed to evaluate the diagnostic accuracy of the 2016 diagnostic criteria for fibromyalgia applied in a population of patients with high impact chronic pain referred for pain rehabilitation. Methods The study was performed as a diagnostic accuracy study at two Danish interdisciplinary pain rehabilitation centers, including 215 participants. All participants were evaluated clinically to identify patients with fibromyalgia. The diagnosis was based on expert opinion, but the minimum requirements were: (1) pain in all four body quadrants and axially for at least three months and (2) minimum 8 of 18 positive tender points. Participants filled in the fibromyalgia survey questionnaire, the patient version of the 2016 diagnostic criteria. Sensitivity, specificity, likelihood ratios, and positive and negative post-test probabilities were calculated using a clinical diagnosis of fibromyalgia as the reference standard. Results Based on clinical diagnosis 45% of the participants were diagnosed with fibromyalgia; of these, only 19% had been diagnosed previously. The 2016 diagnostic criteria demonstrated a sensitivity of 88.5%, a specificity of 81.5%, a positive likelihood ratio of 4.79, a negative likelihood ratio of 0.14, a positive post-test probability of 79.4%, and a negative post-test probability of 10.2%. Conclusions Fibromyalgia was severely under-diagnosed among patients with high impact chronic pain referred to tertiary care in two pain rehabilitation centers in Denmark. The 2016 diagnostic criteria showed sufficient discriminatory properties suggesting that the fibromyalgia survey questionnaire can be used as a screening tool assisting the identification of fibromyalgia in this patient population.

scholarly journals The Diagnostic Accuracy of Сoronary Сomputed Tomography Angiography in the Diagnosis of Stable Coronary Artery Disease in Patients Aged 70 Years and Older

Kardiologiia ◽  
2019 ◽  
Vol 59 (12) ◽  
pp. 28-34
Author(s):  
S. G. Kozlov ◽  
O. V. Chernova ◽  
T. N. Veselova ◽  
S. K. Ternovoy
Keyword(s):  
Chest Pain ◽  
Coronary Artery ◽  
Diagnostic Accuracy ◽  
Positive Result ◽  
Likelihood Ratio ◽  
Stable Coronary Artery Disease ◽  
Post Test ◽  
Artery Disease ◽  
Post Test Probability ◽  
Test Probability

Aim: The purpose of this study was to evaluate the diagnostic accuracy of сoronary сomputed tomography angiography (CCTA) in the diagnosis of stable coronary artery disease (CAD) in patients aged ≥70 years. Materials and methods: The study included 390 patients aged ≥70 years with symptoms suggested stable CAD which underwent elective coronary artery angiography (CAG). Initially the prevalence of angiographically significant CAD was estimated according to the gender and chest pain character, and identifications of patients in whom CCTA was appropriate. After that diagnostic accuracy and сost-efficiency of CCTA in the diagnosis of stable CAD in 82 patients with atypical angina and non-anginal chest pain were evaluated. Results: The prevalence of obstructive CAD in patients with typical angina was very high and they were excluded from the final analysis. Among 82 patients with atypical angina and non-anginal pain which underwent CCTA 48 (59%) patients had obstructive CAD. CСTA data matched with results of CAG in all cases. Among 34 patients that had non-obstructive CAD the results of CCTA and CAG matched in 88% cases. CCTA has sensitivity, specificity, positive predictive value, negative predictive value of 100%, 88%, 92% and 100% respectively. The likelihood ratio for positive result was 8.3, likelihood ratio for negative result was 0.3. Positive result increased post-test probability of obstructive CAD from 42% to 86%, negative result reduced post-test probability of obstructive CAD to 0%. Conclusion: negative CCTA result in patients aged 70 years and older with atypical angina and non-anginal pain allows to exclude the presence of obstructive CAD.  The likelihood ratio for positive result indicates a moderately difference between the pre-test and post-test probability of the presence of obstructive CAD. In patients aged ≥70 years with atypical angina or non-anginal chest pain which have inconclusive results of functional testing or unable undergo functional testing CCTA allows to increase diagnostic yield of CAG and reduce the frequency of minor complications and diagnostic evaluation costs.

Abstract 30: Prediction Scale Thresholds Selected to Rule Out Large Vessel Occlusion Stroke Result in Very Low Positive Predictive Values and Many False Positives

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Kevin J Keenan ◽  
Wade S Smith ◽  
Sara Cole ◽  
Christine Martin ◽  
J Claude Hemphill ◽  
...  
Keyword(s):  
Large Vessel ◽  
Large Vessel Occlusion ◽  
Stroke Patients ◽  
Vessel Occlusion ◽  
Scale Scores ◽  
Post Test ◽  
Suspected Stroke ◽  
Post Test Probability ◽  
Test Probability ◽  
Rule Out

Introduction: Many prior large vessel occlusion (LVO) prevalence and prediction scale accuracy studies have not had samples representative of a prehospital suspected stroke population. To address this, we studied emergency medical systems (EMS) identified prehospital suspected stroke patients brought to the Emergency Department (ED) at Zuckerberg San Francisco General Hospital from July 2017 to July 2018. Methods: Patients were eligible for the prevalence study if the EMS prehospital alert call included suspected stroke with a last known well time within 6 hours and a positive Cincinnati Prehospital Stroke Scale. LVO prediction scale scores were retrospectively calculated from arrival NIHSS subitems. We excluded patients missing NIHSS scores and scales requiring non-NIHSS data. LVO stroke included internal carotid, M1, M2, or basilar arteries. Diagnoses were determined by chart review. Prevalences, scale scores, and accuracy statistics were then calculated. We prespecified that negative results of scale thresholds must reduce the post-test probability to ≤5% to rule out LVO stroke and positive results must increase the post-test probability to ≥80% to rule in LVO stroke. Results: Of 220 EMS transported patients there were 30 LVO strokes (13.6%), 35 ICHs (15.9%), 45 non-LVO strokes (20.5%), and 110 mimics (50%). There were 184 patients eligible for the LVO prediction study. Table 1 shows the accuracy statistics of qualifying scale thresholds. False positive rates ranged from 58% to 80%. Only FAST-ED ≥7 resulted in a positive predictive value (PPV) of ≥80% but this missed 83% of LVO strokes. Conclusions: The prevalence of LVO stroke among EMS suspected acute stroke patients brought to our ED over one year was 13.6%. Prediction scale thresholds selected to rule out LVO stroke result in very low PPVs and many false positives. No scale achieved a PPV above 50% while maintaining a sensitivity above 50% suggesting limitations in the ability of scales to rule in LVO stroke.

scholarly journals Best diagnostic accuracy of sepsis combining SIRS criteria or qSOFA score with Procalcitonin and Mid-Regional pro-Adrenomedullin outside ICU

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Silvia Spoto ◽  
Edoardo Nobile ◽  
Emanuele Paolo Rafano Carnà ◽  
Marta Fogolari ◽  
Damiano Caputo ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Sofa Score ◽  
Consensus Conference ◽  
Post Test ◽  
Qsofa Score ◽  
No Gold Standard ◽  
Post Test Probability ◽  
Test Probability ◽  
Score Evaluation ◽  
Sirs Criteria

Abstract Early diagnosis and treatment significantly reduce sepsis mortality. Currently, no gold standard has been yet established to diagnose sepsis outside the ICU. The aim of the study was to evaluate the diagnostic accuracy of sepsis defined by SIRS Criteria of 1991, Second Consensus Conference Criteria of 2001, modified Second Consensus Conference Criteria of 2001 (obtaining SIRS Criteria and SOFA score), Third Consensus Conference of 2016, in addition to the dosage of Procalcitonin (PCT) and MR-pro-Adrenomedullin (MR-proADM). In this prospective study, 209 consecutive patients with clinical diagnosis of sepsis were enrolled (May 2014–June 2018) outside intensive care unit (ICU) setting. A diagnostic protocol could include SIRS criteria or qSOFA score evaluation, rapid testing of PCT and MR-proADM, and SOFA score calculation for organ failure definition. Using this approach outside the ICU, a rapid diagnostic and prognostic evaluation could be achieved, also in the case of negative SIRS, qSOFA or SOFA scores with high post-test probability to reduce mortality and improve outcomes.

scholarly journals Percent free prostate-specific antigen in assessing the probability of prostate cancer under optimal analytical conditions

1998 ◽  
Vol 44 (12) ◽  
pp. 2462-2470 ◽  
Author(s):  
Massimo Gion ◽  
Riccardo Mione ◽  
Paola Barioli ◽  
Mario Barichello ◽  
Filiberto Zattoni ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Prostate Specific Antigen ◽  
Diagnostic Performance ◽  
False Negative ◽  
Specific Antigen ◽  
Free Psa ◽  
Post Test ◽  
Total Psa ◽  
Post Test Probability ◽  
Test Probability

Abstract Although general consensus exists that percent free prostate-specific antigen (PSA) is superior to total immunoreactive PSA for prostate cancer (CaP) detection, its diagnostic performance is not yet well established. Analytical problems may account for difficulties in evaluating percent free PSA because the free PSA concentration is substantially lower than that of total PSA. The aim of the present study was to establish the diagnostic performances of the IMMULITE percent free PSA assay from Diagnostics Products Corp. under experimental conditions optimized to minimize analytical variability. Eighty-five patients with untreated primary CaP and 261 with untreated benign prostate hypertrophy (BPH) were prospectively enrolled. The Diagnostics Products IMMULITE total (Third Generation) and free PSA were measured by the same technician, using the same instrument and the same reagent batch. We calculated the post-test probability to express how the likelihood of the diagnosis of CaP changed after the percent free PSA was determined. Areas under the ROC curves of percent free PSA were better than those of total PSA in every evaluated range of total PSA. The percent free PSA could have reduced the rate of unnecessary biopsies by 47% in patients with total PSA ≥4 μg/L with only 3.8% false-negative results. The post-test probability of percent free PSA was, however, &lt;50% in men 50–70 years of age, using cutoff points providing sensitivity from 99% to 80%. Percent free PSA is superior to total PSA in distinguishing primary CaP from BPH in patients with total PSA between 2 and 30 μg/L. In men with low total PSA, the diagnostic performance of the percent free PSA assay may be optimized by controlling methodological variability. The percent free PSA assay is effective in reducing the rate of unnecessary biopsies in men with total PSA &gt;4 μg/L. However, the post-test probability provided by percent free PSA is relatively low in asymptomatic patients 50–70 years of age.

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