Rapid diagnostic tests for determining dengue serostatus: a systematic review and key informant interviews

ObjectivesVaccination for dengue with the live attenuated tetravalent CYD-TDV vaccine (Dengvaxia®) is only recommended in individuals who have had prior dengue virus (DENV) infection. Rapid diagnostic tests (RDT) for past DENV infection would offer a convenient method for pre-vaccination screening at point-of-care. A systematic review was conducted to evaluate the performance of current dengue RDTs for determining dengue serostatus, using IgG antibodies against DENV as a marker of past infection.MethodsPubMed and EMBASE databases were searched from 2000 to 2018 to identify studies evaluating dengue RDTs in individuals with known or possible previous DENV infection. Study quality was evaluated using GRADE and QUADAS-2 criteria. Semi-structured interviews were also performed with available dengue RDT manufacturers.ResultsThe performance of four dengue IgG RDTs was determined in 3137 individuals across ten studies conducted in 13 countries, with serum used in most of the studies. No studies reported data for determining dengue serostatus, and limited data were available regarding cross-reactivity with other viruses. The majority of studies demonstrated sensitivities and specificities between 80% and 100% for dengue IgG detection in samples from secondary infection or convalescent time-points after recent infection.ConclusionsAlthough current dengue IgG RDTs have shown reasonable performance compared with laboratory-based tests in secondary infection, additional research is needed to determine how RDTs would perform in relevant populations targeted for vaccination. New RDTs or modifications to current RDTs are feasible and may optimize the performance of these tests for use in a pre-vaccination screening approach.     

Accuracy of cholera rapid diagnostic tests: a systematic review and meta-analysis

BackgroundCholera is an acute diarrheal disease caused by Vibrio cholerae O1 or O139. Cholera rapid diagnostic tests (RDTs) are widely used to screen for cholera cases. However, their accuracy has not been systematically reviewed.ObjectivesTo evaluate the diagnostic accuracy of cholera RDTs.MethodsSystematic review and meta-analysis.Data sourcesMedline, EMBASE and Web of science through to November 2020; references of included studies and a technical guidance on cholera RDTs. This review is registered with PROSPERO (CRD42021233124).Study eligibility criteriaCross-sectional studies comparing the performance of cholera RDTs either to stool culture or PCR.ParticipantsIndividuals with clinically suspected cholera.Data extractionTwo authors independently extracted data and assessed the quality using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) criteria.ResultsEighteen studies were included in the systematic review of which 17 were used for meta-analysis. Crystal VC was the most frequently used RDT (13 studies), followed by Cholkit and Institut Pasteur cholera dipstick (three studies each), SD Bioline (two studies), Artron (one study) and Smart (one study). Using direct testing (n = 12 627 specimens), the bivariate random-effects model yielded a pooled sensitivity and specificity of 91% (95% CI 87%–94%) and 80% (95% CI 74%–84%), respectively. However, through alkaline peptone water (APW) enrichment (n = 3403 specimens), the pooled sensitivity and specificity were 89% (95% CI 79%–95%) and 98% (95% CI 95%–99%), respectively.ConclusionCholera RDTs, especially when enriched with APW, have moderate sensitivity and specificity. Although less useful for clinical management, the current generation of RDTs have clear utility for surveillance efforts if used in a principled manner. Enrichment of stool specimens in APW before using cholera RDTs reduces the possibility of obtaining false-positive results, despite the few cholera cases that go undetected. It is noteworthy that APW-enriched cholera RDTs are not necessarily rapid tests, and are not listed in the Global Task Force on Cholera Control/WHO target product profile.     

Impact of time to antibiotic therapy on clinical outcome in patients with bacterial infections in the emergency department: implications for antimicrobial stewardship

BackgroundRapid initiation of antibiotic treatment is considered crucial in patients with severe infections such as septic shock and bacterial meningitis, but may not be as important for other infectious syndromes. A better understanding of which patients can tolerate a delay in start of therapy is important for antibiotic stewardship purposes.ObjectivesTo explore the existing evidence on the impact of time to antibiotics on clinical outcomes in patients presenting to the emergency department (ED) with bacterial infections of different severity of illness and source of infection.SourcesA literature search was performed in the PubMed/MEDLINE database using combined search terms for various infectious syndromes (sepsis/septic shock, bacterial meningitis, lower respiratory tract infections, urinary tract infections, intra-abdominal infections and skin and soft tissue infections), time to antibiotic treatment, and clinical outcome.ContentThe literature search generated 8828 hits. After screening titles and abstracts and assessing potentially relevant full-text papers, 60 original articles (four randomized controlled trials, 43 observational studies) were included. Most articles addressed sepsis/septic shock, while few studies evaluated early initiation of therapy in mild to moderate disease. The lack of randomized trials and the risk of confounding factors and biases in observational studies warrant caution in the interpretation of results. We conclude that the literature supports prompt administration of effective antibiotics for septic shock and bacterial meningitis, but there is no clear evidence showing that a delayed start of therapy is associated with worse outcome for less severe infectious syndromes.ImplicationsFor patients presenting with suspected bacterial infections, withholding antibiotic therapy until diagnostic results are available and a diagnosis has been established (e.g. by 4–8 h) seems acceptable in most cases unless septic shock or bacterial meningitis are suspected. This approach promotes the use of ecologically favourable antibiotics in the ED, reducing the risks of side effects and selection of resistance.     

Update on rapid diagnostic testing for malaria

To help mitigate the expanding global impact of malaria, with its associated increasing drug resistance, implementation of prompt and accurate diagnosis is needed. Malaria is diagnosed predominantly by using clinical criteria, with microscopy as the current gold standard for detecting parasitemia, even though it is clearly inadequate in many health care settings. Rapid diagnostic tests (RDTs) have been recognized as an ideal method for diagnosing infectious diseases, including malaria, in recent years. There have been a number of RDTs developed and evaluated widely for malaria diagnosis, but a number of issues related to these products have arisen. This review highlights RDTs, including challenges in assessing their performance, internationally available RDTs, their effectiveness in various health care settings, and the selection of RDTs for different health care systems.     

Elevated plasma YKL-40 and risk of infectious disease: a prospective study of 94665 individuals from the general population

ObjectivesYKL-40 is an acute phase protein elevated in patients with infectious and inflammatory diseases. We tested the hypothesis that baseline elevated YKL-40 is associated with increased risk of future infectious disease in healthy individuals in the general population.MethodsWe prospectively followed 94 665 individuals from the Danish general population for up to 23 years and analysed for plasma YKL-40 levels (n = 21 584) and CHI3L1 rs4950928 genotype (n = 94 184). Endpoints were any infection, bacterial pneumonia, urinary tract infection, skin infection, sepsis, diarrhoeal disease, and other infections.ResultsFor YKL-40 percentile category 91–100% versus 0–33%, the multifactorially and C-reactive protein (CRP) adjusted hazard ratios were 1.71 (95% confidence interval 1.50–1.96; p 4 × 10⁻¹⁴) for any infection, 1.97 (1.64–2.37; p 4 × 10⁻¹³) for bacterial pneumonia, 1.62 (1.24–2.11; p 0.002) for urinary tract infection, 1.74 (1.31–2.32; p 2 × 10⁻⁴) for skin infection, 1.76 (1.25–2.46; p 0.004) for sepsis, 1.90 (1.29–2.78; p 0.002) for diarrhoeal disease and 2.71 (1.38–5.35; p 0.01) for other infections. In multifactorially and CRP-adjusted models, a twofold increase in YKL-40 was associated with increased risk of all infectious disease endpoints. Mendelian randomization did not support causality, as CHI3L1 rs4950928 was associated with 94% and 190% higher YKL-40 levels (for CG and CC versus GG genotype), but not with increased risk of any infectious disease endpoint.DiscussionBaseline elevated plasma YKL-40 was not a cause but a strong marker of increased risk of future infectious diseases in individuals in the general population.     

Antimicrobial stewardship in the emergency department: characteristics and evidence for effectiveness of interventions

BackgroundEmergency departments (EDs) are the entrance gates for patients presenting with infectious diseases into the hospital, yet most antimicrobial stewardship programmes are primarily focused on inpatient management. With equally high rates of inappropriate antibiotic use, the ED is a frequently overlooked yet important unit for targeted antimicrobial stewardship (AMS) interventions.ObjectivesWe aimed to (a) describe the specific aspects of antimicrobial stewardship in the ED and (b) summarize the findings from improvement studies that have investigated the effectiveness of antimicrobial stewardship interventions in the ED setting.Sources: (a) a PubMed search for ‘antimicrobial stewardship’ and ‘emergency department’, and (b) published reviews on effectiveness combined with publications from the first source.Content: (a) An in depth analysis of selected publications provided four key antimicrobial use processes typically performed by front-line healthcare professionals in the ED: making a (tentative) clinical diagnosis, starting empirical therapy based on that diagnosis, performing microbiological tests before starting that therapy and following up patients who are discharged from the ED. (b) Further, we discuss the literature on improvement strategies in the ED focusing on guidelines and clinical pathways and multifaceted improvement strategies. We also summarize the evidence of microbiologic culture review.Implications: Based on our review of the literature, we describe four essential elements of antimicrobial use in the ED. Studying the various interventions targeting these care processes, we have found them to be of a variable degree of success. Nonetheless, while there is a paucity of AS studies specifically targeting the ED, there is a growing body of evidence that AS programmes in the ED are effective with modifications to the ED setting. We present key questions for future research.     

Profiling infectious diseases in Turkey after the influx of 3.5 million Syrian refugees

BackgroundSince 2011, the conflict in Syria has led to over five million refugees. Turkey hosts the highest number of Syrian refugees in the world. By February 2019 over 3.6 million people had fled to Turkey to seek safety. Only 6.1% of Syrian refugees live in temporary shelters. Owing to the disrupted healthcare services, many children coming from the conflict zones are less likely to have received vaccination. In temporary shelters immunization coverage is >95% and the refugee population is receptive to vaccination.AimsThe objective of this study was to review the infectious diseases situation among Syrian refugees in Turkey.SourcesWe have reviewed the reports and studies provided by the governmental and non-governmental organizations and obtained more detailed data from the Ministry of Health in Turkey.ContentBetween 2012 and 2016, 1 299 209 cases of respiratory tract infection and 158 058 episodes of diarrhoea with 59 bloody diarrhoeas were reported; 1354 hepatitis A cases and 108 active tuberculosis cases were detected and treated in the temporary shelters for Syrian refugees. Overall in Turkey, 7794 cutaneous leishmaniasis have been reported.ImplicationsSince the influx of Syrian refugees, there has been an increase in cases of leishmaniasis and measles. No significant increase was detected for tuberculosis, other vector-borne infections, and healthcare associated or sexually transmitted infections. The Syrian refugees can be considered as a vulnerable group in Turkey due to their living and working conditions. Based on available data and our detailed analysis, the numbers show a stable situation regarding infectious diseases.     

Optimal use of Rapid Diagnostics in Infection Control and Prevention

Clinical laboratories have implemented rapid diagnostic tests (RDTs) for the identification of bacterial pathogens, with subsequent improvements in antimicrobial stewardship, but these tests may also have a role in infection prevention. Early identification of pathogens by RDTs should allow faster implementation of infection prevention strategies with the goal of reducing transmission. In this review, we assess the use of RDTs as an infection control tool by exploring their role in screening, as well as diagnosis, of methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant gram-negative organisms, Clostridium difficile, and Mycobacterium tuberculosis. This assessment highlights the fact that implementation of RDTs to improve infection prevention will require ongoing collaboration between clinical laboratory personnel, infection prevention departments, and clinicians.     

The diagnostic accuracy of rapid diagnostic tests for Ebola virus disease: a systematic review

BackgroundEbola virus disease (EVD) is a dangerous condition that can cause an epidemic. Several rapid diagnostic tests (RDTs) have been developed to diagnose EVD. These RDTs promise to be quicker and easier to use than the current reference standard diagnostic test, PCR.ObjectivesTo assess the diagnostic accuracy of RDTs for EVD.MethodsA systematic review of diagnostic accuracy studies.Data sourcesThe following bibliographic databases were searched from inception to present: MEDLINE (Ovid), Embase, Global Health, Cochrane Central Register of Controlled Trials, WHO Global Index Medicus database, Web of Science, PROSPERO register of Systematic Reviews, and Clinical Trials.Gov.Study eligibility criteriaDiagnostic accuracy studies.ParticipantsPatients presenting to the Ebola treatment units with symptoms of EVD.InterventionsRDTs; reference standard, RT-PCR.Assessment of risk of biasQuality Assessment of Diagnostic Accuracy Studies-2 tool.Methods of data synthesisSummary estimates of diagnostic accuracy study were produced for each device type. Subgroup analyses were performed for RDT type and specimen material. A sensitivity analysis was performed to assess the effect of trial design and bias.ResultsWe included 15 diagnostic accuracy studies. The summary estimate of sensitivity for lateral flow assays was 86.1% (95% CI, 86–86.2%), with specificity of 97% (95% CI, 96.1–97.9%). The summary estimate for rapid PCR devices was sensitivity of 96.2% (95% CI, 95.3–97.9%), with a specificity of 96.8% (95% CI, 95.3–97.9%). Pre-specified subgroup analyses demonstrated that RDTs were effective on a range of specimen material. Overall, the risk of bias throughout the included studies was low, but it was high in patient selection and uncertain in the flow and timing domains.ConclusionsRDTs possess both high sensitivity and specificity compared with RT-PCR among symptomatic patients presenting to the Ebola treatment units. Our findings support the use of RDTs as a ‘rule in’ test to expedite treatment and vaccination.     

A prospective study to assess the diagnostic performance of the Sofia® Immunoassay for Influenza and RSV detection.

BackgroundRespiratory viruses RSV and influenza A and B viruses are responsible for important disease outbreaks during the winter season in temperate climate regions. Rapid diagnostic tests (RDTs) are assays designed to yield a rapid diagnosis, which facilitates patient management. The Sofia Influenza A + B Fluorescence Immunoassay and Sofia RSV Fluorescence Immunoassay are RDTs for Influenza and RSV detection that employ a new technology to enhance their sensitivity.ObjectivesSensitivity, specificity and positive and negative predictive values of the assays were calculated compared with the reference diagnostic method: real-time RT-PCR.Study designA prospective evaluation was carried out on 1065 respiratory samples for Sofia Influenza A + B FIA and on 261 samples for Sofia RSV FIA from November 2013 to April 2014.ResultsThe sensitivities of the Sofia Influenza A + B FIA for influenza A and influenza B detection were, respectively, 75.3% (244/324) and 50.0% (8/16). The sensitivity of the Sofia RSV FIA was 92.1% (128/139). There were no differences in Sofia FIA performance depending on the virus subtype.ConclusionsThe results showed high sensitivity and specificity values for influenza A and RSV detection, but values were lower for influenza B. More information is needed regarding the performance for influenza B given the small number of positive samples assessed.     

The potential of SARS-CoV-2 antigen-detection tests in the screening of asymptomatic persons

ObjectivesThe aim was to assess the performance of antigen-based rapid diagnostic tests (Ag-RDTs) for SARS CoV-2 when implemented for large-scale universal screening of asymptomatic individuals.MethodsThis study was a pragmatic implementation study for universal Ag-RDT-based screening at a tertiary care hospital in Germany where patients presenting for elective procedures and selected personnel without symptoms suggestive of SARS-CoV-2 were screened with an Ag-RDT since October 2020. Test performance was calculated on an individual patient level.ResultsIn total, 49 542 RDTs were performed in 27 421 asymptomatic individuals over a duration of 5 and a half months. Out of 222 positive results, 196 underwent in-house confirmatory testing with PCR, out of which 170 were confirmed positive, indicating a positive predictive value of 86.7% (95% CI 81.2–91.1%). Negative Ag-RDTs were not routinely tested with PCR, but a total of 94 cases of false negative Ag-RDTs were detected due to PCR tests being performed within the following 5 days with a median cycle threshold value of 33 (IQR 29–35).DiscussionThis study provides evidence that Ag-RDTs can have a high diagnostic yield for transmission relevant infections with limited false positives when utilized at the point of care on asymptomatic patients and thus can be a suitable public health test for universal screening.     

Comparative Evaluation of 11 Commercialized Rapid Diagnostic Tests for Detecting Trypanosoma cruzi Antibodies in Serum Banks in Areas of Endemicity and Nonendemicity

Chagas disease is one of the main public health issues in Latin America. Increasingly during the past few decades, Trypanosoma cruzi infection has been detected in North America, Europe, and the Western Pacific, mainly as a result of population movement. The limited availability of rapid serological diagnostic tests hinders rapid diagnosis and early treatment in areas of endemicity and nonendemicity. In collaboration with 11 national reference laboratories (NRLs) from different geographical areas, we evaluated the performances of commercialized serological rapid diagnostic tests (RDT) for T. cruzi infection. Eleven commercialized T. cruzi infection RDTs were evaluated on a total of 474 samples extensively tested with at least three different techniques for Chagas disease, maintained at controlled low temperatures, and stored in the serum banks of the 11 NRLs. We measured the sensitivity, specificity, and concordance of each RDT and provided an additional questionnaire to evaluate its ease of use. The selected RDTs in this study were performed under controlled laboratory conditions. Out of the 11 RDTs, we found 8 of them to be useful, with the cassette format favored over the strip. We did not observe significant differences in RDT performances in the different regions. Overall, the performance results were lower than those disclosed by the manufacturers. The results of this evaluation validate the possibility of using RDTs to diagnose Chagas disease, thereby decreasing the time to treatment at a primary health care facility for patients who are willing to be treated. Further studies should be conducted in the laboratory and in the field to confirm these data, expressly to evaluate reproducibility in resource-limited settings, or using whole blood in clinical settings in areas of endemicity and nonendemicity.     

Prospective evaluation of a novel multiplex real-time PCR assay for detection of fifteen respiratory pathogens—Duration of symptoms significantly affects detection rate

BackgroundNucleic acid amplification techniques have improved the diagnostic possibilities in respiratory tract infections, although their clinical applicability is not yet fully defined. We have evaluated a multiplex real-time PCR method for the detection of 13 respiratory viruses and 2 bacteria (Mycoplasma and Chlamydophila) in a clinical setting.ObjectivesThe aim of the present study was to evaluate the diagnostic performance and clinical use of a novel multiplex PCR method in adults with community-acquired respiratory viral infection, and the impact of duration of symptoms on detection rates.Study designNasopharyngeal swab samples were prospectively collected from 209 adult outpatients with respiratory infections and 100 asymptomatic controls.ResultsAn infectious agent was identified in 43% of samples from patients and 2% of asymptomatic controls. The detection rate was significantly higher in samples from patients with a duration of symptoms of 6 days or less (51%) than in samples from patients with a duration of symptoms of 7 days or more (30%, p < 0.01). For human corona viruses, and influenza virus A and B there was a correlation between the amount of virus in each patient sample as measured Ct values and duration of symptoms.ConclusionsDuration of symptoms significantly affects the detection rate of respiratory pathogens by multiplex real-time PCR in nasopharyngeal swab samples from adult patients with respiratory infections. Our finding should be taken into account when using these tests in clinical practise.     

Rapid diagnostic tests for the serodiagnosis of human cystic echinococcosis

Cystic echinococcosis (CE) is a parasitic zoonosis especially affecting resource-poor populations in livestock raising areas. Imaging, in particular ultrasound (US), is crucial for the diagnosis, staging, and clinical management of abdominal CE in humans. Serology is a valuable complement to imaging, especially when ultrasound features of CE are absent or unclear. In rural endemic areas, where expertise in US is scant, and conventional serology techniques are unavailable due to lack of laboratory equipment, rapid diagnostic tests (RDTs) may be very useful. Several reports have described the performance of commercial and experimental RDTs in the diagnosis of CE, including a recent study by our group that compared the diagnostic performances of three commercial RDTs for the diagnosis of hepatic CE. To put RDTs for CE in context, we reviewed the available literature in English on this topic. Overall, RDTs appear to be useful in resourcepoor settings where they may replace conventional serodiagnostic tests. However, like other serodiagnostic tests, RDTs lack standardization and show unsatisfactory sensitivity and specificity. An important issue that needs to be addressed is that studies on the diagnostic performance of RDTs fail to take into account the variables known to influence results such as anatomical location and cyst stage.     

Elevated body mass index is associated with an increased risk of infectious disease admissions and mortality: a mendelian randomization study

ObjectiveThe effect of body mass index (BMI) on the risk of infectious diseases admissions and mortality is unclear and is difficult to study given the risks of confounding variables.MethodsWe used genome-wide association studies (GWASs) with mendelian randomization (MR) to obtain causal inference of BMI on the following infectious diseases outcomes: hospital admissions for pneumonia, sepsis, urinary tract infections, skin and soft tissue infections (SSTIs) or all-cause infections. For patients with pneumonia and sepsis, we also analysed their 28-day and 90-day mortalities. The UK Biobank (UKB) cohort (n > 500 000) provided data for GWASs on infectious diseases. The GIANT consortium (n = 681 265) GWAS was used to identify single-nucleotide polymorphisms (SNPs) associated with BMI.ResultsGenetically increased BMI, by one standard deviation, was associated with higher rates of admission due to all infectious disease. The effect was most important for SSTIs (OR: 1.11, 95%CI: 1.09, 1.12). Increasing BMI by one standard deviation was associated with higher pneumonia mortality, especially at 28 days (OR: 1.03, 95%CI: 1.01, 1.05). BMI was not clearly associated with sepsis mortality, although interpretation of the results was limited by a small sample size. There were consistent findings in sensitivity analysis performed by removing highly pleiotropic SNPs and multivariate MR including type-2 diabetes mellitus, estimated glomerular filtration rate, high-density lipoprotein, educational attainment, and a history of smoking.ConclusionsIncreased BMI was associated with increased risk of admission for infectious disease and mortality. While the pathophysiology behind this phenomenon remains unknown, increasing BMI may influence immune dysregulation.     

A Multicenter Study of Real-world Practice for Management of Abnormal Liver Function Tests in Children with Acute Infectious Diseases

BackgroundAbnormal liver function tests (LFTs) are commonly seen in pediatric patients with acute infectious diseases. Few studies and no definite clinical guidelines for these conditions are available. The present study aimed to elucidate the causes and factors associated with prolongation of liver enzyme elevation. We also investigated actual real-world practices in Korea.MethodsA retrospective study was performed on all patients younger than 18 years, who visited six tertiary teaching hospitals around Korea in 2018 for acute infectious diseases and showed alanine aminotransferase (ALT) levels above 60 IU/L without other specific conditions that could cause ALT elevation. We categorized the infections that cause LFT elevation into six groups: respiratory infection, gastrointestinal infection, urinary tract infection, other febrile disease, Epstein-Barr virus infection, and cytomegalovirus infection. We collected data on the medical specialty of the attending physician who followed up the subject, follow-up duration, percentage of follow-up loss, and their investigation.ResultsA total of 613 patients were enrolled in this study, half of whom (50.7%) were younger than 12 months. The mean initial aspartate aminotransferase and ALT values were 171.2 ± 274.1 and 194.9 ± 316.1 IU/L (range 23–2,881, 60–2,949 IU/L), respectively; however, other LFTs were within the normal range. Respiratory infection was the most common diagnosis (45.0%), and rhinovirus was the most commonly identified pathogen (9.8%). The follow-up rate was higher with pediatric gastroenterologists (90.5%) and non-gastroenterology pediatricians (76.4%) than with pediatric residents and emergency doctors. Older age was related to better ALT recovery (odds ratio [OR] of age for month = 1.003; 95% confidence interval [CI], 1.001–1.004; P = 0.004), while the number of infection episodes (OR = 0.626; 95% CI, 0.505–0.777; P < 0.001) was associated with poor ALT recovery. Abdominal sonography was the most commonly used diagnostic tool (36.9%), followed by the hepatotropic virus workup. The modalities of hepatitis workup were significantly differently applied by physicians based on their specialties and institutions.ConclusionAbnormal liver function test after a systemic infection was common in respiratory infection and under the age of 1 year. Age, number of infections, and initial results of LFTs were related to ALT recovery time. Inter-physician, inter-institution, and inter-specialty variances were observed in real-world practice.     

A simplified scoring model for predicting bacteremia in the unscheduled emergency department revisits: The SADFUL score

BackgroundBacteremia is a severe complication of infectious disease. Patients with a high bacteremia risk in the emergency department (ED) but misidentified would lead to the unscheduled revisits. This study aimed to develop a simplified scoring model to predict bacteremia in patients with unscheduled ED revisits.MethodsAdult patients with unscheduled ED revisits within 72 h with a final diagnosis of infectious disease were retrospectively included. The development cohort included patients visiting the ED from January 1, 2019 to December 31, 2021. Internal validation was performed in patients visiting the ED from January 1, 2022 to March 31, 2022. Variables including demographics, pre-comorbidities, triage levels, vital signs, chief complaints, and laboratory data in the index visit were analyzed. Bacteremia was the primary outcome determined by blood culture in either index visits or revisits.ResultsThe SADFUL score for predicting bacteremia comprised the following predictors: “S”egmented neutrophil percentage (+3 points), “A”ge > 55 years (+1 point), “D”iabetes mellitus (+1 point), “F”ever (+2 points), “U”pper respiratory tract symptoms (−2 points), and “L”eukopenia (2 points). The area under receiver operating characteristic curve with 95% confidence interval in the development (1802 patients, 190 [11%] with bacteremia) and the validation cohort (134 patients, 17 [13%] with bacteremia) were 0.78 (0.74–0.81) and 0.79 (0.71–0.88), respectively.ConclusionsThe SADFUL score is a simplified useful tool for predicting bacteremia in patients with unscheduled ED revisits. The scoring model could help ED physicians decrease misidentification of patients at a high risk for bacteremia and potential complications.