Mariska Leeflang

• PhD
• Professor (Assistant) at University of Amsterdam

Objective: Diagnostic test accuracy may vary among healthcare settings, which among other reasons may be due to referral from primary to secondary care. The true magnitude and direction of any difference is not certain. We analyzed the results of meta-analyses of diagnostic test accuracy to compare sensitivity and specificity between patients in no...

Objectives To explore patient, carer and clinician experiences of the QbTest and its impact on patient outcomes for attention deficit hyperactivity disorder (ADHD) diagnosis and medication management. Design Mixed-methods systematic review. Data sources MEDLINE, EMBASE, PsycINFO, CINAHL, ClinicalTrials.gov and WHO ICTRP (from inception to Septemb...

Various open science practices have been proposed to improve the reproducibility and replicability of scientific research, but not for all practices, there may be evidence they are indeed effective. Therefore, we conducted a scoping review of the literature on interventions to improve reproducibility. We systematically searched Medline, Embase, Web...

Background Sample collection is a key driver of accuracy in the diagnosis of SARS‐CoV‐2 infection. Viral load may vary at different anatomical sampling sites and accuracy may be compromised by difficulties obtaining specimens and the expertise of the person taking the sample. It is important to optimise sampling accuracy within cost, safety and acc...

Background Functional constipation is common in children and accurate diagnostic methods are essential for early diagnosis and effective management. The diagnostic accuracy of transabdominal ultrasound to diagnose functional constipation is unclear. Objective To evaluate the diagnostic accuracy of transverse rectal diameter measurement via transab...

The prediction of the risk of developing complications after colorectal surgery for colorectal carcinoma remains imprecise. Body composition measurements on a computed tomography (CT) scan can potentially contribute to a better preoperative risk assessment. The aim of this systematic review is to evaluate the evidence for the use of body compositio...

Article highlights Introduction Some people have loss of function (LOF) alleles in the CYP2C19 gene, which reduce the effectiveness of clopidogrel (antiplatelet medicine). Point of care tests (POCT) can be used near-patient to quickly detect these alleles and guide alternative treatment. In this systematic review, we assessed the accuracy and tech...

Background Many interventions, especially those linked to open science, have been proposed to improve reproducibility in science. To what extent these propositions are based on scientific evidence from empirical evaluations is not clear. Aims The primary objective is to identify Open Science interventions that have been formally investigated regar...

Background Clinical and laboratory diagnosis of cutaneous leishmaniasis (CL) is hampered by under-ascertainment of direct microscopy. Methods This study compared the diagnostic accuracy of qPCR on DNA extracted from filter paper to the accuracy of direct smear slide microscopy in participants presenting with a cutaneous lesion suspected of leishma...

Objective: To evaluate open science policies of imaging journals, and compliance to these policies in published articles. Methods: From imaging journals listed we extracted open science policy details: protocol registration, reporting guidelines, funding, ethics and conflicts of interest (COI), data sharing, and open access publishing. The 10 most...

Background Several open science-promoting initiatives have been proposed to improve the quality of biomedical research, including initiatives for assessing researchers’ open science behaviour as criteria for promotion or tenure. Yet there is limited evidence to judge whether the interventions are effective. This review aimed to summarise the litera...

Background Many interventions, especially those linked to open science, have been proposed to combat the reproducibility crisis. To what extent these propositions are based on scientific evidence from empirical evaluations is not clear. Aims The primary objective is to identify interventions that have been formally investigated regarding their infl...

Background: Although many predictive parameters have been studied, an internationally accepted, validated predictive model to predict the clinical outcome of asphyxiated infants suffering from hypoxic-ischemic encephalopathy is currently lacking. The aim of this study was to identify, appraise and summarize available clinical prediction models, an...

Background This is a systematic review and meta-analysis of diagnostic test accuracy studies to assess the predictive value of both TST and IGRA for active TB among SOT recipients. Methods Medline, Embase, and the CENTRAL databases were searched from 1946 until June 30, 2022. Two independent assessors extracted data from studies. Sensitivity analy...

There is an urgent need for biosurveillance of unregulated African meat imports at border points of entry in destination markets. This is underscored by recent pandemics linked to exotic wildlife products. Our objective was to catalog the quantity of meat that is informally transported from Africa into and through Europe often without any veterinar...

This article provides a practical guide for clinicians and radiologists to critically evaluate diagnostic accuracy systematic reviews when using them to inform clinical decisions. Systematic reviews of diagnostic accuracy studies can provide the best available evidence to inform decisions regarding the use of a diagnostic test. In this guide, the...

Objectives: To assess the prevalence of overly positive interpretation - also called 'spin'- of results in diagnostic accuracy studies of infectious diseases and to identify suggestions for improvement. Methods: A PubMed search was performed to identify diagnostic accuracy studies of infectious diseases published between January and March 2019....

Objective: To elicit the relative importance of the benefits and harms of colorectal cancer (CRC) screening among potential screening participants in the Dutch population. Methods: In a consensus meeting with 11 experts, risk reduction of CRC and CRC deaths (benefits) and complications from colonoscopy, stress of receiving positive fecal immunol...

Background: Novel blood-based protein biomarkers may be of value for efficient, accurate, and non-invasive diagnosis of pancreatic cancer. This study assesses the diagnostic accuracy of newly recognized blood-based protein biomarkers for detecting pancreatic cancer, and investigates their added value to CA19-9, the common blood-based biomarker in c...

Supplementary data for "Diagnostic accuracy and added value of blood-based protein biomarkers for pancreatic cancer: A meta-analysis of aggregate and individual participant data." Full article: https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(22)00476-X/fulltext

Background: Echocardiogram is the reference standard for the diagnosis of haemodynamically significant patent ductus arteriosus (hsPDA) in preterm infants. A simple blood assay for brain natriuretic peptide (BNP) or amino-terminal pro-B-type natriuretic peptide (NT-proBNP) may be useful in the diagnosis and management of hsPDA, but a summary of th...

Background: The diagnostic challenges associated with the COVID-19 pandemic resulted in rapid development of diagnostic test methods for detecting SARS-CoV-2 infection. Serology tests to detect the presence of antibodies to SARS-CoV-2 enable detection of past infection and may detect cases of SARS-CoV-2 infection that were missed by earlier diagno...

Introduction Self-report questionnaires to screen for symptoms of common mental disorders (CMDs) are commonly used as inexpensive, easy-to-administer tools in research and clinical practice. However, their validity to detect the presence of any CMD across cultures and languages is unclear. Psychometrically sound and brief case-finding instruments a...

Background Mucosal Leishmaniasis (ML), a neglected tropical disease caused by Leishmania parasites, impairs the quality of life of under-resourced populations in South America. If not treated promptly, this disease progresses to facial deformities and death. The low sensitivity of microscopy results and the unavailability of other accurate tests ha...

Background: Biparametric (bp)-MRI and multiparametric (mp)-MRI may improve the diagnostic accuracy of renal mass histology. Purpose: To evaluate the available evidence on the diagnostic accuracy of bp-MRI and mp-MRI for solid renal masses in differentiating malignant from benign, aggressive from indolent, and clear cell renal cell carcinoma (ccR...

Background: Accurate rapid diagnostic tests for SARS-CoV-2 infection would be a useful tool to help manage the COVID-19 pandemic. Testing strategies that use rapid antigen tests to detect current infection have the potential to increase access to testing, speed detection of infection, and inform clinical and public health management decisions to r...

Background: Good patient adherence to antiretroviral (ART) medication determines effective HIV viral suppression, and thus reduces the risk of progression and transmission of HIV. With accurate methods to monitor treatment adherence, we could use simple triage to target adherence support interventions that could help in the community or at health...

Whereas diagnostic tests help detect the cause of signs and symptoms, prognostic tests assist in evaluating the probable course of the disease and future outcome. Studies to evaluate prognostic tests are longitudinal, which introduces sources of bias different from those for diagnostic accuracy studies. At present, systematic reviews of prognostic...

Background Cellular tests for Lyme borreliosis might be able to overcome major shortcomings of serological testing, such as its low sensitivity in early stages of infection. Therefore, we aimed to assess the sensitivity and specificity of three cellular tests. Methods This was a nationwide, prospective, multiple-gate case-control study done in the...

Background: COVID-19 illness is highly variable, ranging from infection with no symptoms through to pneumonia and life-threatening consequences. Symptoms such as fever, cough, or loss of sense of smell (anosmia) or taste (ageusia), can help flag early on if the disease is present. Such information could be used either to rule out COVID-19 disease,...

Background: Our March 2021 edition of this review showed thoracic imaging computed tomography (CT) to be sensitive and moderately specific in diagnosing COVID-19 pneumonia. This new edition is an update of the review. Objectives: Our objectives were to evaluate the diagnostic accuracy of thoracic imaging in people with suspected COVID-19; assess...

Introduction: Cardiovascular disorders are increasingly recognised as important fall risk factors in older adults. Falls are a major public health problem in older adults, and therefore, effective interventions for reducing falls are essential for this population. Cardiovascular disease is a clinically relevant (but often overlooked) and potential...

Introduction: The brain magnetic resonance imaging (MRI) result is a major predictor for the outcome of term infants with perinatal asphyxia who underwent therapeutic hypothermia. In daily practice, no uniform method is used to assess these images. Purpose: The aim of this study was to determine which MRI-score best predicts adverse outcome at 2...

Background: Systematic screening in high-burden settings is recommended as a strategy for early detection of pulmonary tuberculosis disease, reducing mortality, morbidity and transmission, and improving equity in access to care. Questioning for symptoms and chest radiography (CXR) have historically been the most widely available tools to screen fo...

The performance of diagnostic tests crucially depends on the disease prevalence, test sensitivity, and test specificity. However, these quantities are often not well known when tests are performed outside defined routine lab procedures which make the rating of the test results somewhat problematic. A current example is the mass testing taking place...

Background: Despite the nearly ubiquitous reported use of peer review among reputable medical journals, there is limited evidence to support the use of peer review to improve the quality of biomedical research and in particular, imaging diagnostic test accuracy (DTA) research. Purpose: To evaluate whether peer review of DTA studies published by...

Background Preferential publication of studies with positive findings can lead to overestimation of diagnostic test accuracy (i.e. publication bias). Understanding the contribution of the editorial process to publication bias could inform interventions to optimize the evidence guiding clinical decisions. Purpose/Hypothesis To evaluate whether accu...

Background Self-report screening instruments are frequently used as scalable methods to detect common mental disorders (CMDs), but their validity across cultural and linguistic groups is unclear. We summarized the diagnostic accuracy of brief questionnaires on symptoms of depression, anxiety and posttraumatic stress disorder (PTSD) among Arabic-spe...

Background Allogeneic hematopoietic stem cell transplantation (SCT) is the only established curative treatment option for patients with sickle cell disease (SCD). Transplantations with an HLA-identical matched sibling donor (MSD) have resulted in excellent disease-free survival of >90% and overall survival (OS) of >95%. However, lack of HLA-identic...

Comparative diagnostic test accuracy studies assess and compare the accuracy of 2 or more tests in the same study. Although these studies have the potential to yield reliable evidence regarding comparative accuracy, shortcomings in the design, conduct, and analysis may bias their results. The currently recommended quality assessment tool for diagno...

Background Point-of-care tests could be essential in differentiating bacterial and viral acute community-acquired lower respiratory tract infections and driving antibiotic stewardship in community. Objectives To assess diagnostic test accuracy of point-of-care tests in community settings for acute community-acquired lower respiratory tract infecti...

Background: Allogeneic hematopoietic stem cell transplantation (SCT) is the only established curative treatment option for patients with sickle cell disease (SCD). However, lack of HLA-identical sibling donors is a limiting factor. Haploidentical related donors are a promising pool of donors, potentially extending SCT as a curative treatment optio...

Objective To describe the discrimination and calibration of clinical prediction models, identify characteristics that contribute to better predictions and investigate predictors that are associated with unplanned hospital readmissions. Design Systematic review and meta-analysis. Data source Medline, EMBASE, ICTPR (for study protocols) and Web of...

Background An assessment of the validity of individual diagnostic accuracy studies in systematic reviews is necessary to guide the analysis and the interpretation of results. Such an assessment is performed for each included study and typically reported at the study level. As studies may differ in sample size and disease prevalence, with larger stu...

Objectives: (1) To identify and classify comparative diagnostic test accuracy (DTA) study designs; and (2) to describe study design labels used by authors of comparative DTA studies. Methods: We performed a methodological review of 100 comparative DTA studies published between 2015 and 2017, randomly sampled from studies included in 238 comparative...

Objectives: This article provides GRADE guidance on how authors of evidence syntheses and health decision makers, including guideline developers, can rate the certainty across a body of evidence for comparative test accuracy questions. Study design and setting: This guidance extends the previously published GRADE guidance for assessing certainty of...

Testing for SARS-CoV-2 infection is key in managing the current pandemic. More than 1700 preprints and peer reviewed journal articles evaluating tests for SARS-CoV-2 infection have been published as of January 2021. However, evaluations of these studies have identified many methodological issues, leading to a high risk of bias and difficulties appl...

Background: Accurate rapid diagnostic tests for SARS-CoV-2 infection could contribute to clinical and public health strategies to manage the COVID-19 pandemic. Point-of-care antigen and molecular tests to detect current infection could increase access to testing and early confirmation of cases, and expediate clinical and public health management d...

For many users of the biomedical literature, abstracts may be the only source of information about a study. Hence, abstracts should allow readers to evaluate the objectives, key design features, and main results of the study. Several evaluations have shown deficiencies in the reporting of journal and conference abstracts across study designs and re...

Background: The respiratory illness caused by SARS-CoV-2 infection continues to present diagnostic challenges. Our 2020 edition of this review showed thoracic (chest) imaging to be sensitive and moderately specific in the diagnosis of coronavirus disease 2019 (COVID-19). In this update, we include new relevant studies, and have removed studies wit...

Background: The clinical implications of SARS-CoV-2 infection are highly variable. Some people with SARS-CoV-2 infection remain asymptomatic, whilst the infection can cause mild to moderate COVID-19 and COVID-19 pneumonia in others. This can lead to some people requiring intensive care support and, in some cases, to death, especially in older adul...

Background: Concerns are raised about missed, delayed and inappropriate diagnosis of Lyme Borreliosis. Quantitative descriptive studies have demonstrated non-adherence to the guidelines for testing for Lyme Borreliosis. Objectives: To gain insight into the diagnostic practices that general practitioners apply for Lyme Borreliosis, their motives for...

Context: In the last few decades, data acquisition and processing has seen tremendous amount of growth, thus sparking interest in machine learning (ML) within the health care system. Objective: Our aim for this review is to provide an evidence map of the current available evidence on ML in pediatrics and adolescent medicine and provide insight f...

Background: The respiratory illness caused by SARS-CoV-2 infection continues to present diagnostic challenges. Early research showed thoracic (chest) imaging to be sensitive but not specific in the diagnosis of coronavirus disease 2019 (COVID-19). However, this is a rapidly developing field and these findings need to be re-evaluated in the light o...

Comparative accuracy studies evaluate the relative performance of two or more diagnostic tests. As any other form of research, such studies should be reported in an informative manner, to allow replication and to be useful for decision‐making. In this study we aimed to assess whether and how components of test comparisons were reported in comparati...

Background Specific diagnostic tests to detect severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and resulting COVID‐19 disease are not always available and take time to obtain results. Routine laboratory markers such as white blood cell count, measures of anticoagulation, C‐reactive protein (CRP) and procalcitonin, are used to assess th...

Background Management and control of coronavirus disease 2019 (COVID-19) relies on reliable diagnostic testing. Objectives To evaluate the diagnostic test accuracy (DTA) of nucleic acid amplification tests (NAATs) for the diagnosis of coronavirus infections. Data sources PubMed, Web of Science, the Cochrane Library, Embase, Open Grey and conferen...

Background: COVID-19 is arguably the most important public health concern in 2020 worldwide, and efforts are now escalating to suppress or eliminate its spread. Objective: In this study, we undertook a meta-analysis to estimate the global and regional SARS-CoV-2 seroprevalence rates in humans, and to assess whether seroprevalence associates with ge...

Objective: To estimate the effect of an intervention compared to the usual peer-review process on reducing spin in the abstract’s conclusion of biomedical study reports. Study Design and Setting: We conducted a two-arm, parallel-group RCT in a sample of primary research manuscripts submitted to BMJ Open. Authors received short instructions alongsid...

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Background: In children with urinary tract infection (UTI), only those with pyelonephritis (and not cystitis) are at risk for developing long-term renal sequelae. If non-invasive biomarkers could accurately differentiate children with cystitis from children with pyelonephritis, treatment and follow-up could potentially be individualized. This is a...

Background: COVID-19 is arguably the number-one public health concern worldwide, and efforts are now escalating to control its spread. Objective: In this study, we undertake a meta-analysis to estimate the global and regional anti-SARS-CoV-2 seroprevalence rates in humans and assess whether seroprevalence associates with geographical, climatic and...

Background: The diagnosis of infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents major challenges. Reverse transcriptase polymerase chain reaction (RT-PCR) testing is used to diagnose a current infection, but its utility as a reference standard is constrained by sampling errors, limited sensitivity (71% to 98%),...

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting COVID-19 pandemic present important diagnostic challenges. Several diagnostic strategies are available to identify or rule out current infection, identify people in need of care escalation, or to test for past infection and immune response. Point-of-care ant...

Background Individual Patient Data meta‐analyses (IPD‐MA) are regarded as the gold standard for systematic reviews, which also applies to systematic reviews of diagnostic test accuracy (DTA) studies. An increasing number of DTA systematic reviews with IPD‐MA have been published in recent years, but there is much variation in how these IPD‐MA were p...

Systematic reviews of diagnostic test accuracy (DTA) studies are fundamental to the decision making process in evidence based medicine. Although such studies are regarded as high level evidence, these reviews are not always reported completely and transparently. Suboptimal reporting of DTA systematic reviews compromises their validity and generalis...

Objective Comparative diagnostic test accuracy systematic reviews (DTA reviews) assess the accuracy of two or more tests and compare their diagnostic performance. We investigated how comparative DTA reviews assessed the risk of bias (RoB) in primary studies that compared multiple index tests. Study Design and Setting Overview of comparative DTA re...

Background: Some people with SARS-CoV-2 infection remain asymptomatic, whilst in others the infection can cause mild to moderate COVID-19 disease and COVID-19 pneumonia, leading some patients to require intensive care support and, in some cases, to death, especially in older adults. Symptoms such as fever or cough, and signs such as oxygen saturat...

The aim of our study was to investigate the reproducibility of diagnostic accuracy meta-analyses, as reported in published systematic reviews. We selected all systematic reviews of diagnostic test accuracy containing a meta-analysis, published in January 2018 and retrieved in Medline through OVID. All reviews reported a summary estimate of sensitiv...

Background and purpose Cardiac thrombi are an important cause of embolic stroke. We studied the diagnostic yield and diagnostic accuracy of cardiac CT angiography (CTA) compared to echocardiography for detection of cardiac thrombi in ischemic stroke patients.Methods We performed a systematic review and meta-analysis of the literature on cardiac CTA...

Background: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus and resulting COVID-19 pandemic present important diagnostic challenges. Several diagnostic strategies are available to identify current infection, rule out infection, identify people in need of care escalation, or to test for past infection and immune response. Ser...