Quality Of Diagnostic Accuracy Studies Research Articles

An assessment of the characteristics and quality of diagnostic accuracy studies for positron emission tomography conducted in Japan: a systematic review.

BackgroundSystematic evaluations of the diagnostic accuracy of positron emission tomography (PET) imaging have been widely conducted in many countries. Although Japan’s total number of PET units is the second highest in the world, very limited effort has been made to systematically assess the methodological quality of PET studies in Japan. We performed a systematic review to assess the characteristics and quality of PET diagnostic accuracy studies conducted in Japan and to analyze the factors related to their quality.MethodsAll PET studies conducted in Japan were identified using MEDLINE and the Japan Medical Society Database. The characteristics of the Japanese studies were examined and their methodological quality evaluated by the standardized quality assessment of diagnostic accuracy studies (QUADAS) tool. We compared the quality of studies indexed in MEDLINE with non-indexed studies, followed by a comparison of the studies’ conclusions with those of international health technology assessment (HTA) reports.ResultsA total of 138 studies were identified. Half of them were not indexed in MEDLINE. The mean quality score of the Japanese studies was 6.7 and the proportion of high-quality studies (with a quality score higher than 8) was 32.6%. A significant difference was observed in several quality items between MEDLINE-indexed and non-indexed studies, although there was no difference in total quality score. Three variables (i.e., target diseases, publication year, and study type) were identified as factors related to the quality of the studies. Conclusions of Japanese studies relating to several target diseases were relatively consistent with international assessments.ConclusionsAlthough a considerable number of diagnostic accuracy studies of PET have been conducted in Japan, a substantial proportion of high-quality studies were not indexed in international databases. High-quality Japanese studies, therefore, should be searched using Japanese databases and assessed by systematic reviews and HTA conducted internationally.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-015-0084-4) contains supplementary material, which is available to authorized users.

EUS-Guided FNA for Diagnosis of Pancreatic Cystic Lesions: a Meta-Analysis

Background: Preoperative diagnosis of pancreatic cystic lesions (PCLs) must be reliable as the current standard treatment, major or total pancreatectomy, dramatically affects quality of life. Additionally, early diagnosis of malignancy is essential to an improved prognosis. The diagnostic accuracy of fluid analysis using endoscopic ultrasonography-guided fine-needle aspiration (EUS-FNA) has been demonstrated in pancreatic solid lesions. The utility of this technique in the diagnosis of PCLs is still unknown. Methods: A comprehensive search was performed in multiple databases. Studies differentiating benign and malignant PCLs via EUS-FNA were included in this meta-analysis. The quality of diagnostic accuracy studies (QUADAS) was adopted to evaluate the selected studies. Pooled sensitivity, specificity, likelihood ratio, diagnostic odds ratio, and summary receiver operating characteristic (sROC) curve analyses were conducted. Two main classification types of malignancy were characterized and analyzed. We also generated a subgroup analysis of available clinical factors. Publication bias was evaluated by Begg's and Egger's tests. Results: Sixteen studies containing 1024 subjects have been published. The pooled sensitivity for malignant cytology according to classification 1 was 0.51 (95% CI, 0.45-0.58), and pooled specificity was 0.94 (95% CI, 0.92-0.96). When the detected PCLs were identified as classification 2, suspicious malignancy or potential malignancy, sensitivity and specificity were similar, 0.52 (95% CI, 0.46-0.57) and 0.97 (95% CI, 0.95-0.98) respectively. Conclusion: This meta-analysis demonstrates that EUS-FNA is a reliable clinical tool for the diagnosis of PCLs. However, a more accurate algorithm is needed to reduce various biases and to improve the sensitivity of EUS-FNA in the detection of malignant PCLs.

A systematic review of the PTSD Checklist's diagnostic accuracy studies using QUADAS.

Despite the popularity of the PTSD Checklist (PCL) as a clinical screening test, there has been no comprehensive quality review of studies evaluating its diagnostic accuracy. A systematic quality assessment of 22 diagnostic accuracy studies of the English-language PCL using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) assessment tool was conducted to examine (a) the quality of diagnostic accuracy studies of the PCL, and (b) whether quality has improved since the 2003 STAndards for the Reporting of Diagnostic accuracy studies (STARD) initiative regarding reporting guidelines for diagnostic accuracy studies. Three raters independently applied the QUADAS tool to each study, and a consensus among the 4 authors is reported. Findings indicated that although studies generally met standards in several quality areas, there is still room for improvement. Areas for improvement include establishing representativeness, adequately describing clinical and demographic characteristics of the sample, and presenting better descriptions of important aspects of test and reference standard execution. Only 2 studies met each of the 14 quality criteria. In addition, study quality has not appreciably improved since the publication of the STARD Statement in 2003. Recommendations for the improvement of diagnostic accuracy studies of the PCL are discussed.

Quality Appraisal of Diagnostic Accuracy Studies in Fine-Needle Aspiration Cytology: A Survey of Risk of Bias and Comparability

The quality of diagnostic accuracy studies is determined by 2 key factors: risk of bias and comparability. Bias can distort accuracy estimates and poor reporting impairs comparability. While diagnostic accuracy studies for fine-needle aspiration cytology (FNAC) are frequently published, the methodologic issues associated with this body of literature have never been reviewed. To assess the quality of design and reporting of diagnostic test accuracy studies in FNAC. Diagnostic accuracy studies were identified by a Medline (US National Library of Medicine) search. Sixty-four FNAC diagnostic test accuracy studies were randomly selected for structured review with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) survey. Studies were divided between 2 time periods: 2000-2001 and 2009-2011. Diagnostic test accuracy studies of FNAC suffer from numerous deficiencies in study design, which negatively affect the reliability of accuracy estimates.

Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity

To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool. Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy. The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item ("Uninterpretable Results") showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with "no fulfilment" increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy. The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies. • Good methodological quality is a basic requirement in diagnostic accuracy studies. • Most coronary CT angiography studies have only been of moderate design quality. • Weak methodological quality will affect the sensitivity and specificity. • No improvement in methodological quality was observed over time. • Authors should consider the QUADAS checklist when undertaking accuracy studies.

Diagnostic Test Studies in Nephrology: Quantity, Quality, and Scope

Diagnostic errors represent an important cause of preventable harm in health care that may be reduced through evidence-based choice, use, and interpretation of diagnostic tests. We hypothesized that diagnostic errors are reduced through evidence-based choice, use, and interpretation of diagnostic tests. Retrospective cohort study. Diagnostic test studies. Publications from 1966-2008 retrieved from MEDLINE. The Quality of Diagnostic Accuracy Studies (QUADAS) tool. Number and coverage of diagnostic studies in nephrology and methodological quality of the test accuracy subset. Fewer diagnostic studies were published in nephrology than other areas of internal medicine, although the proportion of total citations that were diagnostic studies (4.9% ± 2.8% [SD]) was not statistically different from other specialties (P = 0.2). Within nephrology, some topic areas (eg, urinary tract infections) were over-represented, whereas others (eg, acute kidney injury) had relatively few diagnostic studies (range, 2.7%-12.5%). Examining the randomly selected subset of studies that were diagnostic test accuracy studies (120) showed variable quality. Ninety-seven percent (116 of 120) of studies adequately described index test procedure, but only 27% (32 of 120) adequately blinded investigators to results of index tests, and 36% (43 of 120), to results of reference tests. The quality of nephrology diagnostic test accuracy studies has not improved substantially during the past 30 years. Comparing nephrology with other specialties, some potential inequalities of scale could not be addressed, which may influence research output results across specialties. Diagnostic research in nephrology is published less frequently than most other medical specialties. The quality of diagnostic test accuracy studies that are published is variable and leaves room for improvement.

Measures of chemotherapy‐induced peripheral neuropathy: a systematic review of psychometric properties

Chemotherapy-induced peripheral neuropathy (CIPN) remains the principal dose-limiting toxicity of many agents. This systematic review evaluates available CIPN measures and provides rationale for selection of measures in this field. Searches of Medline (1966-2010), CINAHL (1966-2010), Embase (1966-2010), and Cochrane (1988-2010) databases were performed. To be selected, studies had to include (1) subjects receiving peripheral neurotoxic chemotherapy for cancer and (2) a primary purpose of psychometric evaluation of CIPN measures. A modified Quality of Diagnostic Accuracy Studies (QUADAS) tool coded psychometric study quality, with 0-7 score overall possible (higher score indicating better quality). A total of 15 studies qualified for evaluation. Overall studies were of moderate quality, with 10 of 15 receiving a 4-5 QUADAS score. Averaged quality scores for two repeatedly studied measures, Total Neuropathy Score (TNS) versions and Functional Assessment of Cancer-Gynecologic Oncology Group, neurotoxicity (FACT/GOG-Ntx), were 5.4 and 4.5, respectively. Two measures emerged as potentially useful for clinical trials and patient care. The FACT/GOG-Ntx is a subjective measure of CIPN-related quality of life (QoL). TNS clinical versions incorporate both subjective measures and objective examinations of nerve function. However, to improve QUADAS scoring, additional research is needed focusing on other psychometric aspects such as responsiveness of CIPN outcome measures.

Diagnostic accuracy of vision screening tests for the detection of amblyopia and its risk factors: a systematic review

This systematic review evaluates the diagnostic accuracy of preschool vision screening tests for the detection of amblyopia and its risk factors. The literature searches were conducted in nine bibliographic databases. No limitation to a specific study design, year of publication or language was applied. Studies were included if they compared a vision screening test with a reference test (gold standard) in children from the general population. In addition, the studies had to provide sufficient data to calculate diagnostic accuracy (sensitivity and specificity). Full-text articles were assessed for studies that satisfied the inclusion criteria using the "Quality of Diagnostic Accuracy Studies (QUADAS)" checklist. Two studies with a longitudinal design and 25 cross-sectional studies met the inclusion criteria. One of the longitudinal studies compared a screening programme in children between 1 and 2 years of age with a re-examination at the age of 8. The sensitivity for the screening programme was 86% (range: 64-97%) and the specificity 99% (range: 98-99%). The second longitudinal study compared screening examinations at 8, 12, 18, 25 and 31 months, with a re-examination at the age of 37 months. In this study, the sensitivity of the screening examination increased with age, while the specificity remained unchanged. The cross-sectional studies evaluated different screening settings, visual acuity tests, auto- or photorefractors and stereo tests. A large variety of reference tests, differing criteria for defining amblyopia and its risk factors and methodological limitations of the studies prevented a valid data interpretation. Diagnostic test accuracy of preschool vision screening tests can only be sufficiently investigated after establishing age-related values defining amblyopia, refractive errors and binocular disorders. To address these questions, we recommend a controlled longitudinal study design.

PHQ-9 and PHQ-2 in Western Kenya

To the Editors:—Recently, Monahan et al. concluded that the PHQ-2 and PHQ-9 were “valid/reliable for assessing DSM-IV depressive disorders and depression severity among adults living with HIV/AIDS in Western Kenya”1. However, they did not actually use any accepted assessment tool to diagnose DSM-IV depressive disorders. Instead, they used a “diagnosis” of depression based on the self-report PHQ-9 as their criterion standard. A recent meta-analysis2 found that the PHQ-9 was acceptable for depression screening, but it was not superior to results from other depression screening tools in identifying cases of depression,3 and it was poorly sensitive in some patient groups2. Based on the authors use of the PHQ-9 as a diagnostic criterion, one might conclude that any depression questionnaire could appropriately be substituted for a gold standard structured interview. This is clearly not the case, and the PHQ-9 is not appropriate for that purpose either. Monahan et al. arrived at an inflated estimate of the performance of the PHQ-2 by committing the error of incorporation bias, in which the PHQ-2 was validated against the PHQ-9, of which it is a subset. This method will always produce favorable, albeit unrealistic, results. QUADAS, which is a tool for assessing the quality of diagnostic accuracy studies,4 contains an item explicitly assessing whether the reference criterion was independent of the index test: this study violates that standard. Monahan et al.’s favorable assessment of the PHQ-2 contradicts a more measured conclusion from a recent meta-analysis that found that ultra-short depression screens like the PHQ-2 have high false-positive rates and should only be used as an initial method to rule out diagnoses5. Monahan et al. minimized findings that the PHQ-9 had only moderate test-test stability, which is inconsistent with their claims it was validly assessing clinically significant DSM-IV depressive disorders. They also minimized indications from focus groups that patients were “challenged” by the response format. Overall, the authors’ conclusion that the PHQ can be implemented in understaffed Kenyan clinics to enhance care for depression is troubling and contradicts a meta-analysis that clearly indicated that introducing screening for depression does not improve depression outcomes without a substantial infusion of resources6. Based on evidence, there is no reason to believe that introducing PHQ screening in Kenya would benefit patients, and such claims retard the attraction of sufficient resources and reorganization of care systems that would be required to improve depression care.

Assessing the quality of diagnostic studies using psychometric instruments: applying QUADAS

There has been an increase in the number of systematic reviews of diagnostic tests, which has resulted in the introduction of two checklists: statement for reporting of diagnostic accuracy (STARD) and quality assessment of diagnostic accuracy studies (QUADAS). To examine the validity and usefulness of QUADAS when applied to diagnostic accuracy studies using psychometric instruments and to examine the quality in reporting of these studies during practical application of the checklist. Two reviewers independently rated the quality of 54 studies using QUADAS. The proportion of agreement was used to assess overall agreement and individual agreement of QUADAS items between reviewers. The overall agreement between the two reviewers for all QUADAS items combined was 85.7%. The proportion of agreement between reviewers for each item ranged from just over 57-100% and was over 80% for 8 of the items. The poorest agreement was associated with the items for selection criteria, indeterminate results and withdrawals. None of the studies adequately reported all relevant information to enable all QUADAS item to be scored as 'yes'. Overall QUADAS was relatively easy to use and appears to be an acceptable tool for appraising the quality of diagnostic accuracy studies using psychometric instruments. The application of QUADAS was hampered by the poor quality of reporting encountered.

Diagnostic Imaging Practice Guidelines for Musculoskeletal Complaints in Adults—An Evidence-Based Approach—Part 3: Spinal Disorders

Purpose To develop evidence-based diagnostic imaging practice guidelines to assist chiropractors and other primary care providers in decision making for the appropriate use of diagnostic imaging for spinal disorders. Methods A comprehensive search of the English and French language literature was conducted using a combination of subject headings and keywords. The quality of the citations was assessed using the Quality of diagnostic accuracy studies (QUADAS), the Appraisal of Guidelines Research and Evaluation (AGREE), and the Stroke Prevention and Educational Awareness Diffusion (SPREAD) evaluation tools. The Referral Guidelines for Imaging (radiation protection 118) coordinated by the European Commission served as the initial template. The first draft was sent for an external review. A Delphi panel composed of international experts on the topic of musculoskeletal disorders in chiropractic radiology, clinical sciences, and research were invited to review and propose recommendations on the indications for diagnostic imaging. The guidelines were pilot tested and peer reviewed by practicing chiropractors, and by chiropractic and medical specialists. Recommendations were graded according to the strength of the evidence. Results Recommendations for diagnostic imaging guidelines of adult spine disorders are provided, supported by more than 385 primary and secondary citations. The overall quality of available literature is low, however. On average, 45 Delphi panelists completed 1 of 2 rounds, reaching more than 85% agreement on all 55 recommendations. Peer review by specialists reflected high levels of agreement, perceived ease of use of guidelines, and implementation feasibility. Dissemination and implementation strategies are discussed. Conclusions The guidelines are intended to be used in conjunction with sound clinical judgment and experience and should be updated regularly. Future research is needed to validate their content.

Diagnostic Imaging Guideline for Musculoskeletal Complaints in Adults—An Evidence-Based Approach—Part 2: Upper Extremity Disorders

Purpose To develop evidence-based diagnostic imaging practice guidelines to assist chiropractors and other primary care providers in decision making for the appropriate use of diagnostic imaging for upper extremity disorders. Methods A comprehensive search of the English and French language literature was conducted using a combination of subject headings and keywords. The quality of the citations was assessed using the Quality of diagnostic accuracy studies (QUADAS), the Appraisal of Guidelines Research and Evaluation (AGREE), and the Stroke Prevention and Educational Awareness Diffusion (SPREAD) evaluation tools. The Referral Guidelines for Imaging (radiation protection 118) coordinated by the European Commission served as the initial template. The first draft was sent for an external review. A Delphi panel composed of international experts on the topic of musculoskeletal disorders in chiropractic radiology, clinical sciences, and research was invited to review and propose recommendations on the indications for diagnostic imaging. The guidelines were pilot tested and peer-reviewed by practicing chiropractors and by chiropractic and medical specialists. Recommendations were graded according to the strength of the evidence. Dissemination and implementation strategies are discussed. Results Recommendations for diagnostic imaging guidelines of adult upper extremity disorders are provided, supported by over 126 primary and secondary citations. The overall quality of available literature is low, however. On average, 44 Delphi panelists completed 1 of 2 rounds, reaching over 88% agreement on all 32 recommendations. Peer review by specialists reflected high levels of agreement and perceived ease of use of guidelines and implementation feasibility. Conclusions The guidelines are intended to be used in conjunction with sound clinical judgment and experience and should be updated regularly. Future research is needed to validate their content.

Diagnostic Imaging Practice Guidelines for Musculoskeletal Complaints in Adults—An Evidence-Based Approach: Part 1: Lower Extremity Disorders

Purpose The aim of this study was to develop evidence-based diagnostic imaging practice guidelines to assist chiropractors and other primary care providers in decision making for the appropriate use of diagnostic imaging of lower extremity disorders. Methods A comprehensive search of the English and French language literature was conducted using a combination of subject headings and keywords. The quality of the citations was assessed using the Quality of Diagnostic Accuracy Studies (QUADAS), the Appraisal of Guidelines Research and Evaluation (AGREE), and the Stroke Prevention and Educational Awareness Diffusion (SPREAD) evaluation tools. The Referral Guidelines for Imaging (Radiation Protection 118) coordinated by the European Commission served as the initial template. The first draft was sent for external review. A Delphi panel composed of international experts on the topic of musculoskeletal disorders in chiropractic radiology, clinical sciences, and research were invited to review and propose recommendations on the indications for diagnostic imaging. The guidelines were pilot tested and peer reviewed by field chiropractors, and by chiropractic and medical specialists. Recommendations were graded according to the strength of the evidence. Results Recommendations for diagnostic imaging guidelines of adult lower extremity disorders are provided, supported by more than 174 primary and secondary citations. Except for trauma, the overall quality of available literature is low. On average, 57 Delphi panelists completed 1 of 2 rounds, reaching more than 83% agreement on all 56 recommendations. Peer review by specialists reflected high levels of agreement, perceived ease of use of guidelines, and implementation feasibility. Conclusions The guidelines are intended to be used in conjunction with sound clinical judgment and experience and should be updated regularly. Dissemination and implementation strategies are discussed. Future research is needed to validate their content.

The quality of diagnostic accuracy studies since the STARD statement

To assess whether the quality of reporting of diagnostic accuracy studies has improved since the publication of the Standards for the Reporting of Diagnostic Accuracy studies (STARD statement). The quality of reporting of diagnostic accuracy studies published in 12 medical journals in 2000 (pre-STARD) and 2004 (post-STARD) was evaluated by two reviewers independently. For each article, the number of reported STARD items was counted (range 0 to 25). Differences in completeness of reporting between articles published in 2000 and 2004 were analyzed, using multilevel analyses. We included 124 articles published in 2000 and 141 articles published in 2004. Mean number of reported STARD items was 11.9 (range 3.5 to 19.5) in 2000 and 13.6 (range 4.0 to 21.0) in 2004, an increase of 1.81 items (95% CI: 0.61 to 3.01). Articles published in 2004 reported the following significantly more often: methods for calculating test reproducibility of the index test (16% vs 35%); distribution of the severity of disease and other diagnoses (23% vs 53%); estimates of variability of diagnostic accuracy between subgroups (39% vs 60%); and a flow diagram (2% vs 12%). The quality of reporting of diagnostic accuracy studies has improved slightly over time, without a more pronounced effect in journals that adopted the STARD statement. As there is still room for improvement, editors should mention the use of the STARD statement as a requirement in their guidelines for authors, and instruct reviewers to check the STARD items. Authors should include a flow diagram in their manuscript.

Development and validation of methods for assessing the quality of diagnostic accuracy studies

Development and validation of methods for assessing the quality of diagnostic accuracy studies

Interrater Reliability in Assessing Quality of Diagnostic Accuracy Studies Using the QUADAS Tool: A Preliminary Assessment

Quality Assessment of Diagnostic Accuracy Studies (QUADAS) is a new tool to measure the methodological quality of diagnostic accuracy studies in systematic reviews. We used data from a systematic review of magnetic resonance spectroscopy (MRS) in the characterization of suspected brain tumors to provide a preliminary evaluation of the inter-rater reliability of QUADAS. A structured literature search identified 19 diagnostic accuracy studies. These publications were distributed randomly to primary and secondary reviewers for dual independent assessment. Reviewers recorded methodological quality by using QUADAS on a custom-designed spreadsheet. We calculated correlation, percentage of agreement, and kappa statistic to assess inter-rater reliability. Most studies in our review were judged to have used an accurate reference standard. Conversely, the MRS literature frequently failed to specify the length of time between index and reference tests or that the clinicians were unaware of the index test findings when reporting the reference standard. There was good correlation (rho = 0.78) between reviewers in assessment of the overall number of quality criteria met. However, mean agreement for individual QUADAS questions was only fair (kappa = 0.22) and ranged from no agreement beyond chance (kappa < 0) to moderate agreement (kappa = 0.58). Inter-rater reliability in our study was relatively low. Nevertheless, we believe that QUADAS potentially is a useful tool for highlighting the strengths and weaknesses of existing diagnostic accuracy studies. Low reliability suggests that different reviewers will reach different conclusions if QUADAS is used to exclude "low-quality" articles from meta-analyses. We discuss methods for improving the validity and reliability of QUADAS.

Challenges in Systematic Reviews of Diagnostic Technologies

Diagnostic tests are critical components of effective health care. They help determine treatments that are most beneficial for a given patient. Their assessment is a complex process that includes such challenges as a dearth of studies that evaluate clinical outcomes and lack of data on use of the test in realistic clinical settings. The methodologic quality of studies of diagnostic tests also lags behind the quality of studies of therapeutic interventions. Statistical methods to combine diagnostic accuracy data are more complex and not as well developed, leading to difficulties in the interpretation of results. The Agency for Healthcare Research and Quality Technology Assessment Program has adopted a 6-level framework for evaluating diagnostic technologies. The model emphasizes the need for systematic reviews of diagnostic test studies to go beyond the assessment of technical feasibility and accuracy to examine the impact of the test on health outcomes. In this paper, we use examples from 3 Evidence-based Practice Center reports to illustrate 3 challenges reviewers may face when reviewing diagnostic test literature: finding relevant studies, assessing methodologic quality of diagnostic accuracy studies, and synthesizing studies that evaluate tests in different patient populations or use different outcomes.

A Toxicologist's Guide to Studying Diagnostic Tests

Diagnostic testing plays an important role in medicine, including in clinical toxicology. In comparison with therapeutics however, until recently, much less focus has been input in this vital area of research and practice. In the absence of stringent and constructive criteria, the quality and interpretability of studies evaluating diagnostic accuracy has been less than optimal. Recently, a group of researchers and clinicians have attempted to outline a checklist intended to provide guidelines for undertaking and reporting studies examining diagnostic accuracy. Also, a tool to assess the quality of diagnostic accuracy studies was developed. The purpose of this review is to inform practitioners and researchers in the field of clinical toxicology on the basic concepts underlying measurements of the accuracy of diagnostic tests, methodological concerns related to design and analysis of studies, the strengths and weaknesses of different measures of accuracy and an overview of the Standards for Reporting Diagnostic Accuracy (STARD statement) and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Understanding key concepts in the field of diagnostic testing can not only help improve future studies but also explain why diagnostic tests currently used by clinical toxicologists are not performing well in particular circumstances.

A Toxicologist's Guide to Studying Diagnostic Tests

Diagnostic testing plays an important role in medicine, including in clinical toxicology. In comparison with therapeutics however, until recently, much less focus has been input in this vital area of research and practice. In the absence of stringent and constructive criteria, the quality and interpretability of studies evaluating diagnostic accuracy has been less than optimal. Recently, a group of researchers and clinicians have attempted to outline a checklist intended to provide guidelines for undertaking and reporting studies examining diagnostic accuracy. Also, a tool to assess the quality of diagnostic accuracy studies was developed. The purpose of this review is to inform practitioners and researchers in the field of clinical toxicology on the basic concepts underlying measurements of the accuracy of diagnostic tests, methodological concerns related to design and analysis of studies, the strengths and weaknesses of different measures of accuracy and an overview of the Standards for Reporting Diagnostic Accuracy (STARD statement) and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Understanding key concepts in the field of diagnostic testing can not only help improve future studies but also explain why diagnostic tests currently used by clinical toxicologists are not performing well in particular circumstances.

A systematic review finds that diagnostic reviews fail to incorporate quality despite available tools

Background and objective To review existing quality assessment tools for diagnostic accuracy studies and to examine to what extent quality was assessed and incorporated in diagnostic systematic reviews. Methods Electronic databases were searched for tools to assess the quality of studies of diagnostic accuracy or guides for conducting, reporting or interpreting such studies. The Database of Abstracts of Reviews of Effects (DARE; 1995–2001) was used to identify systematic reviews of diagnostic studies to examine the practice of quality assessment of primary studies. Results Ninety-one quality assessment tools were identified. Only two provided details of tool development, and only a small proportion provided any indication of the aspects of quality they aimed to assess. None of the tools had been systematically evaluated. We identified 114 systematic reviews, of which 58 (51%) had performed an explicit quality assessment and were further examined. The majority of reviews used more than one method of incorporating quality. Conclusion Most tools to assess the quality of diagnostic accuracy studies do not start from a well-defined definition of quality. None has been systematically evaluated. The majority of existing systematic reviews fail to take differences in quality into account. Reviewers should consider quality as a possible source of heterogeneity.