Archives of Academic Emergency Medicine. 2023; 11(1): e49 REV I EW ART I C L E Point-Of-Care Ultrasonography for Identification of Skin and Soft Tissue Abscess in Adult and Pediatric Patients; a Systematic Review and Meta-Analysis Erfan Rahmani1, Ehsan Fayyazishishavan2, Arian Afzalian1, Sanaz Varshochi1, Reza Amani-Beni3, Seyed-Amirabbas Ahadiat4, Zeynab Moshtaghi5, Seyyed-Ghavam Shafagh6, Roya Khorram7, Elnaz Asadollahzade8, Raihaneh Atbaei9, Mohammad Saeed Kahrizi10, Atoosa Rahbari11, Negar Baharlouie3, Farzaneh Mostanbet12, Bahamin Amirabadiquchani13, Moein Kiani14, Mozhdeh memarizadeh12, Shahin Keshtkar Rajabi15, Reza Barati6, Hengame Hajinouri16, Shahrzad Najafi1, Zeynab Abdollahi17, Nahid Dadashzadehasl18, Atousa Moghadam Fard26, Mozhgan Afshar19, Atefeh Abedi20, Sara Saeidi21, Adeleh Mansourirad22, Pedram Emami Shahrezaei23, Sepideh Shah Hosseini6, Zahra Rostami Ghotbabadi12, Reza Vafadar24, Roozbeh Roohinezhad6, Nogol Ghalamkarpour25, Mehrdad Farrokhi26∗ 1. Graduated, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2. Department of Biostatistics and Data Science, School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA. 3. School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 4. Girona University, Girona, Spain. 5. Graduated, Faculty of Nursing, Bushehr University of Medical Sciences, Bushehr, Iran. 6. School of Medicine, Iran University of Medical Sciences, Tehran, Iran. 7. Bone and Joint Diseases Research Center, Department of Orthopedic Surgery, Shiraz University of Medical Sciences, Shiraz, Iran. 8. Multiple Sclerosis Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran. 9. School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran. 10.School of Medicine, Alborz University of Medical Sciences, Karaj, Iran. 11.Islamic University of Azad Medical Branch, Tehran, Iran. 12.School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran. 13.Mashhad University of Medical Sciences, Mashhad, Iran. 14.School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran. 15.Firoozabadi hospital clinical research development unit (FHCRDU), Department of internal medicine, school of medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran. 16.School of Medicine, Islamic Azad University, Tehran, Iran. 17.Department of Radiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 18.Legal Medicine Research Center, Iranian Legal Medicine Organization, Tehran, Iran. 19.University of Psychology Sciences, South Azad Tehran, Iran. 20.Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. 21.Students Research Committee, Faculty of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. 22.Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA. 23.Islamic Azad University of Najafabad, Najafabad, Iran. 24.Department of Orthopedic Surgery, Kerman University of Medical Sciences, Kerman, Iran. 25.Department of Clinical Laboratory Sciences, School of Allied Medicine, Student Research Committee, Lorestan University of Medical Sciences, Khorramabad, Iran. 26.ERIS Research Institute, Tehran, Iran. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 2 Received: May 2023; Accepted: June 2023; Published online: 16 July 2023 Abstract: Introduction: Differentiating the soft tissue abscess from other types of skin and soft tissue infections (SSTIs) poses a particular challenge because they have similar physical evaluation findings, but each disease has a different course, outcome, and treatment. This meta-analysis aimed to investigate the diagnostic accuracy of point-of-care ultrasonog- raphy for diagnosis of soft tissue abscess in the emergency departments. Methods: A comprehensive literature search of MEDLINE, Scopus, Web of Science, Embase, and Google Scholar, from inception to January 2023, was conducted to identify relevant studies investigating the diagnostic performance of point-of-care ultrasonography for identification of abscess. Methodological quality of the included studies was assessed using a revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Results: The pooled estimates of diagnostic parameters of ultrasonography for diagnosis of abscess were as follows: sensitivity, 0.93 (95% CI: 0.92–0.94); specificity, 0.87 (95% CI: 0.85–0.89), and the area under the summary receiver-operating characteristic (SROC), 0.95. The pooled sensitivity, specificity, and area under the SROC of studies in adult patients were 0.98 (95% CI: 0.92–1), 0.92 (95% CI: 0.86–0.95), and 0.99, respectively. The pooled sensitivity, specificity, and area under the SROC of studies in pediatric patients were 0.9 (95% CI: 0.87–0.92), 0.78 (95% CI: 0.73–0.82), and 0.91, respectively. Conclusion: Our meta-analysis demonstrated that the point-of-care ul- trasonography has excellent diagnostic value for the abscess in the emergency department. Furthermore, we found that the diagnostic performance of point-of-care ultrasonography for diagnosis of abscess was higher for adult cases than for pediatric patients. Keywords: Abscess; cellulitis; diagnostic imaging; meta-analysis; ultrasonography Cite this article as: Rahmani E, Fayyazishishavan E, Afzalian A, Varshochi S, Amani-Beni R, et al. Point-Of-Care Ultrasonography for Identi- fication of Skin and Soft Tissue Abscess in Adult and Pediatric Patients; a Systematic Review and Meta-Analysis. Arch Acad Emerg Med. 2023; 11(1): e49. https://doi.org/10.22037/aaem.v11i1.2021. 1. Introduction Skin and soft tissue infections (SSTIs) are a highly preva- lent presenting complaint in the ambulatory setting and also emergency department (1, 2). Recent investigations have shown that although the rise of methicillin-resistant Staphy- lococcus aureus can lead to significant increase in admis- sion rates, duration of hospitalizations, and ambulatory and emergency department visits, most patients with suspected abscess are treated in emergency departments using incision and drainage as the gold standard of care (3, 4). Differenti- ating the soft tissue abscess from other types of SSTIs pose a particular challenge because they have similar physical eval- uation findings, but each disease has a different course, out- come, and treatment. Indeed, cases with abscess are man- aged using drainage, whereas patients with cellulitis are com- monly treated using systematic antibiotics (1). This misclas- sification can lead to unnecessary invasive interventions, ex- posure to sedation-related adverse events, and inappropri- ate management in patients with cellulitis (5). It has been shown that point-of-care ultrasonography as an adjunct to physical evaluations can improve the accuracy of diagnosis of skin abscess in cases with SSTIs and result in change in the decision to perform incision and drainage (6). A num- ber of studies have in fact shown that point-of-care ultra- ∗Corresponding Author: Mehrdad Farrokhi; ERIS Research Institute, Tehran, Iran. Email: dr.mehrdad.farrokhi@gmail.com, Phone number: +989384226664, ORCID: https://orcid.org/0000-0002-1559-2323. sonography is superior to physical evaluation alone for di- agnosis of abscess, but there is limited evidence supporting its efficacy in the emergency departments (7-9). Further- more, conflicting findings have been reported in the litera- ture regarding the accuracy of point-of-care ultrasonography for evaluation of SSTIs in the emergency departments (10, 11). In addition, previous investigations of point-of-care ul- trasonography for diagnosis of abscess in pediatrics showed less consistency in comparison with data from investigations in adults, emphasizing the importance of further diagnos- tic studies (8, 11-13). Although majority of previous studies suggest the point-of-care ultrasonography for evaluation of SSTIs in the emergency department, systematic reviews and meta-analyses are required to determine the exact diagnostic accuracy of this imaging modality. Therefore, this systematic review and meta-analysis aimed to investigate the diagnos- tic accuracy of point-of-care ultrasonography for diagnosis of soft tissue abscess in the emergency departments and also the subgroup of pediatric patients. 2. Methods 2.1. Search strategy This systematic review and meta-analysis of diagnostic stud- ies was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses for Diagnos- tic Test Accuracy (PRISMA-DTA) guidelines. A comprehen- sive literature search of MEDLINE, Scopus, Web of Science, Embase, and Google Scholar, from inception to January 2023, was conducted to identify relevant studies investigating the This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 3 Archives of Academic Emergency Medicine. 2023; 11(1): e49 diagnostic performance of point-of-care ultrasonography for diagnosis of abscess. Our searches were limited to peer- reviewed published papers and abstracts in English. More- over, the references of the relevant papers were manually screened for the potential studies. The systematic search was performed using Medical Subject Heading (MeSH) terms, keywords, and Boolean operators: “Ultrasound” OR “Ultra- sonography” OR “Sonography” OR “Sono” OR “Ultrasonic” OR “Sonogram” AND “Skin and soft tissue infections” OR “SSTI” OR “SSTIs” OR “Soft tissue infections” OR “Skin Dis- eases, Infectious” OR “Staphylococcal Skin Infections” OR “Soft Tissue Injuries” OR “Suppuration” OR “Suppurate” OR “pus” OR “abscess” OR “Cellulitis” OR “Gram positive infec- tion” OR “Bacterial infection”. 2.2. Study selection and eligibility criteria Results from the electronic database search were assessed by two independent authors (MF and RAB) based on the key- words included in title and abstract for relevance and eval- uated for inclusion criteria based on full text. Since screen- ing process was managed using EndNote software, any dupli- cate studies were initially removed from the results. Any dis- crepancies and disagreements regarding studies evaluated for possible eligibility based on title and abstract or inclu- sion based on full text were resolved by discussion and con- sultation with a third author. The papers were included in the study if they evaluated the diagnostic accuracy of point- of-care ultrasonography for diagnosis of abscess, reported a 2 × 2 table containing true positive (TP), false positive (FP), true negative (TN), and false negative (FN), reported an orig- inal study or a case series with more than 10 cases, and pub- lished in English. We excluded systematic reviews and meta- analyses, case reports, case series with less than 10 patients, editorials, studies without extractable data to provide a 2 × 2 table, and papers published in languages other than English. 2.3. Data extraction Two independent authors (AM and MF) extracted data from each included study using a standardized data extraction sheet. Data extracted from each study included first au- thor, publication year, sample size, country, study location, mean age, sex, study design, prevalence of abscess, study population, diagnostic performance of point-of-care ultra- sonography (TP, TN, FP, FN, sensitivity, and specificity), and gold standard. Any disagreements throughout data extrac- tion were resolved through discussion with a third author. 2.4. Methodological quality assessment Two independent authors (MF and RAB) separately assessed the methodological quality of the included studies using a re- vised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2) tool. Any discrepancies about the re- sults of this tool were resolved through consultation with a third author. 2.5. Statistical analysis Statistical analysis was conducted using meta-Disc software version 1.4 (Ramona Cajal Hospital, Madrid, Spain) and Stata statistical software package (Stata Corp., College Station, TX, USA) (version 17.0). We used Cochrane Q-test and I2 to eval- uate the heterogeneity among the included studies. A P-value less than 0.05 for Q-test or I2 higher than 50% indicate a significant heterogeneity among the included studies and a random-effects model was used. On the other hand, if P- value of Q-test was higher than 0.05 and I2 was less than 50%, a fixed-effects model was used for estimation of diagnostic parameters. Publication bias was investigated using Funnel plot and Begg’s test. We calculated Spearman’s rank correla- tion coefficient to assess the threshold effects. 3. Results 3.1. Search results Initial search of the electronic databases yielded a total of 2564 studies, after which 917 duplicate papers were ex- cluded. From the 1647 nonduplicate studies, 1602 stud- ies were excluded after title and abstract screening. Forty- five studies were chosen for full-text evaluation. Afterwards, 30 studies were excluded due to having poor quality, non- extractable data, and being irrelevant. As a result, 15 stud- ies met all eligibility criteria and were included in this meta- analysis. Figure 1 shows the PRISMA flowchart of inclusion and exclusion of the studies. 3.2. Characteristics of the included studies The included studies encompassed 2615 patients, ranging from a minimum of 23 to a maximum of 1216. These stud- ies were published between 1997 and 2020. Thirteen of the included studies were performed in USA, one in Ireland, and one in Lebanon. The reported mean age and the percentage of females ranged from 1.95 to 42 years and 31% to 64%, re- spectively. Fourteen studies had prospective observational design and one study was a clinical trial. Table 1 summarizes the main characteristics of the 15 included studies. 3.3. Methodological quality of the included stud- ies Table 2 presents our evaluation of the risk of bias and ap- plicability domains of the 15 included studies in this meta- analysis using QUADAS-2 tool. Overall, the majority of the studies were considered to have low risk of bias and applica- bility concerns. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 4 3.4. Screening performance characteristics of ul- trasonography Spearman’s correlation coefficient for ultrasonography was 0.11 with a P value of 0.7, demonstrating that there is no threshold effect. There was a significant between- study heterogeneity for sensitivity (I2=74.4% and P<0.01), specificity (I2=81% and P<0.01), positive likelihood ratio (PLR) (I2=83.8% and P<0.01), negative likelihood ratio (NLR) (I2=79% and P<0.01), and diagnostic odds ratio (DOR) (I2=80.6% and P<0.01). The pooled estimates of diagnos- tic parameters of ultrasonography for diagnosis of abscess were as follows: sensitivity, 0.93 (95% CI: 0.92–0.94); speci- ficity, 0.87 (95% CI: 0.85–0.89); positive likelihood ratio, 6.23 (95% CI: 3.91–9.92); negative likelihood ratio, 0.09 (95% CI: 0.05–0.15); and diagnostic odds ratio, 95.66 (95% CI: 40.46–226.18) (Figures 2-6). The area under the SROC curve for the accuracy of ultrasonography to diagnose abscess in the emergency settings was 0.95 (Fig. 7). 3.5. Subgroup analysis The pooled sensitivity, specificity, PLR, NLR, and area un- der SROC of studies (n=4) in adult patients were 0.98 (95% CI: 0.92–1), 0.92 (95% CI: 0.86–0.95), 9.02 (95% CI: 4.31- 18.87), 0.03 (95% CI: 0.01-0.08), and 0.99, respectively. The pooled sensitivity, specificity, PLR, NLR, and area under SROC of studies (n=7) in pediatric patients were 0.9 (95% CI: 0.87–0.92), 0.78 (95% CI: 0.73–0.82), 4.08 (95% CI: 3.11-5.37), 0.14 (95% CI: 0.08-0.25), and 0.91, respectively. 3.6. Publication bias Results of Begg’s test (P=0.58) and Egger’s test (P=0.30) re- vealed that there was no significant publication bias in the included studies. Similarly, the funnel plot of the studies showed no significant publication bias (Fig. 8). 4. Discussion In this systematic review and meta-analysis, we investigated the diagnostic accuracy of point-of-care ultrasonography for diagnosis of abscess in the emergency department and also the subgroups of pediatric and adult patients. The over- all sensitivity, specificity, and accuracy of point-of-care ul- trasonography for diagnosis of abscess were 0.93, 0.87, and 0.96, respectively. The sensitivity, specificity, and accuracy of point-of-care ultrasonography for diagnosis of abscess in adult patients were 0.98, 0.92, and 0.99, respectively. The meta-analysis of studies on pediatric cases found that the pooled sensitivity, specificity, and accuracy of point-of-care ultrasonography for diagnosis of abscess are 0.9, 0.78, and 0.91, respectively. These findings show that overall diagnos- tic performance of point-of-care ultrasonography for diagno- sis of abscess is acceptable. However, the pooled estimates of diagnostic parameters revealed that sensitivity, specificity, and accuracy of point-of-care ultrasonography for diagnosis of abscess in pediatric patients is lower than those of adult cases. This may in part be clarified by differences between adult and pediatric cases with respect to the body habitus, as larger body sizes of adult patients may increase accuracy of point-of-care ultrasonography for detection of drainable abscesses. Moreover, final diagnosis of abscess is confirmed by incision and drainage and this procedure may require not only pain control, but also conscious sedation. Conse- quently, collaboration of the patients or their parents for fur- ther evaluations can be affected, which may reduce the ac- curacy of point-of-care ultrasonography for diagnosis of ab- scess. In a randomized clinical trial by Gaspari et al. (14), 125 cases presenting to emergency department with soft tissue abscess were randomized to incision and drainage with physical ex- amination or incision and drainage with point-of-care ultra- sonography. The main assessed outcome in this study was failure of treatment at 10 days. The results of this study showed that point-of-care ultrasonography in addition to di- agnosis of abscess, can reduce the rate of failure or need for repeated incision and drainage in patients with soft tissue abscess. However, since the vast majority of the included studies in our meta-analysis did not investigate the effect of point-of-care ultrasonography on the rate of treatment fail- ure, we were not able to predict the pooled value of this out- come. In a similar systematic review and meta-analysis by Subra- maniam et al. (15), several electronic databases including Embase, Web of Science, CINAHL, Cochran, and MEDLINE were systematically searched from inception to 2015 to find studies evaluating the diagnostic performance of point-of- care ultrasonography for identification of abscess in emer- gency departments. They included four studies on adult pa- tients and two studies on pediatric patients with a total num- ber of 800 cases. They reported that sensitivity and speci- ficity of point-of-care ultrasonography for diagnosis of ab- scess were 0.97 and 0.83, respectively. These parameters were higher than those calculated in our meta-analysis. One pos- sible explanation for this inconsistency could be the differ- ence between our meta-analysis and their study with respect to the number of included studies and the total number of as- sessed cases. Moreover, since they only reported the overall sensitivity and specificity of point-of-care ultrasonography for diagnosis of abscess, their findings may not be generaliz- able to pediatric population. Indeed, we found that the sen- sitivity and specificity of point-of-care ultrasonography for diagnosis of abscess are lower in pediatric cases compared to adult patients; therefore, we believe that this approach of Subramanian et al. misrepresents the reported results for diagnostic performance of this imaging modality. The role This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 5 Archives of Academic Emergency Medicine. 2023; 11(1): e49 of point-of-care ultrasonography in diagnosis of abscess is particularly crucial for the pediatric cases because they may not tolerate sedation and incision and drainage. Since we found that point-of-care ultrasonography has acceptable di- agnostic characteristics for diagnosis of abscess in pediatric cases, its use may reduce the rate of unnecessary painful and anxiety-provoking treatment (16, 17). Similar to the study of Subramaniam et al., in another sys- tematic review and meta-analysis by Alsaawi et al. (18) the data of only four studies were pooled to estimate the diagnos- tic characteristics of point-of-care ultrasonography for diag- nosis of abscess. However, this study described the range of diagnostic characteristics of point-of-care ultrasonography and the overall pooled estimates of these variables were not reported. 5. Limitations We acknowledge some limitations in our systematic review and meta-analysis of the studies investigating the diagnos- tic characteristics of point-of-care ultrasonography for diag- nosis of abscess. First, we found significant heterogeneity among the included studies. Although this was in part addressed by conducting subgroup analysis on pediatric and adult’s patients, other factors such as lack of a common follow-up and difference in the use of index test may also contribute to heterogeneity. Second, some of the included studies were rated as unclear or high risk of bias on the patient selection and flow and timing do- mains. Third, the vast majority of the included studies had small sample sizes and the data of two studies were not ex- tractable for meta-analysis. Therefore, further original stud- ies with improved methods of patient selection and higher sample sizes are required to establish the results of this meta- analysis. 6. Conclusion Our meta-analysis demonstrated that point-of-care ultra- sonography has excellent diagnostic value for abscess diag- nosis in emergency departments. Furthermore, we found that the diagnostic performance of point-of-care ultrasonog- raphy in diagnosis of abscess was higher for adult cases than for pediatric patients. However, since the conclusion of this meta-analysis was based on a limited number of studies with small sample sizes, further investigations are required to es- tablish point-of-care ultrasonography for diagnosis of ab- scess in all age groups. 7. Declarations 7.1. Acknowledgments The authors thank all those who contributed to this study. 7.2. Conflict of interest None. 7.3. Funding and support None. 7.4. Authors’ contribution All authors contributed to study design, data collection, and writing the draft of the study. All authors read and approved the final version of manuscript. 7.5. Data Availability Not applicable. 7.6. Using artificial intelligence chatbots None. References 1. Hersh AL, Chambers HF, Maselli JH, Gonzales R. 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ABSCESS: applied bedside sonography for convenient evaluation of superficial soft tissue infections. Acad Emerg Med. 2005;12(7):601-6. 25. Page-Wills C, Simon BC, Christy D, Levitt MA. Utility of ultrasonography on emergency department manage- ment of suspected cutaneous abscess. Acad Emerg Med. 2000;7(5):493. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 7 Archives of Academic Emergency Medicine. 2023; 11(1): e49 Table 1: The main characteristics of the studies included in the meta-analysis Authors Year# Country Type Location Population Age (year) Female % Prevalence of abscess Reference standard Knaysi et al. (3) 2020 Lebanon Obs ED Adults 46 * 46.8 42 I&D or Follow-up Gaspari et al. (14) 2019 USA CT ED Adults 32.5 43 NR I&D or Follow-up Mower et al. (19) 2019 USA Obs ED Adults and Pediatrics 36 52 68 I&D or Follow-up Levine et al. (11) 2019 USA Obs PED Pediatrics 5.3 37% 30 Radiology Department Imaging Lam et al. (13) 2018 USA Obs ED Pediatrics NR NR 58 I&D or Follow-up Greenlund et al. (20) 2017 USA Obs Clinic NR NR NR NR NR Adams et al. (12) 2016 USA Obs PED Pediatrics 7* 54% 68 I&D or Follow-up Marin et al. (8) 2013 USA Obs PED Pediatrics 7* 57% 62 I&D Berger et al. (21) 2012 USA Obs ED Adults NR NR 85 I&D Iverson et al. (22) 2012 USA Obs PED Pediatrics 5.2 64% 62 I&D Sivitz et al. (23) 2010 USA Obs PED Pediatrics 9.5 42% 44 I&D or Follow-up Tayal et al. (9) 2006 USA Obs ED Adults 42 47 43 I&D or Follow-up Squire et al. (24) 2005 USA Obs ED Adults 39 31% 60 I&D or Follow-up Page-Wills et al. (25) 2000 USA Obs ED NR NR NR 71 I&D Quraishi et al. (10) 1997 Ireland Obs PED Pediatrics 1.95 56% 74 I&D or Follow-up All included studies had prospective design; Age is presented as mean except in studies marked with “*” which is presented as median. #: year of publication; ED: emergency department; PED: pediatric ED; CT: clinical trial; Obs: observational; I&D: Incision and drainage; NR: Not reported; USA: United States of America. Table 2: Quality assessment of the included studies using QUADAS-2 tool Study Risk of bias Applicability concerns Patient selection Index test Reference standard Flow and timing Patient selection Index test Reference standard Knaysi et al. § § Gaspari et al. ? ? Mower et al. ? Levine et al. ? ? Lam et al. ? ? Greenlund et al. ? ? ? Adams et al. ? ? Marin et al. ? ? Berger et al. ? Iverson et al. ? § § Sivitz et al. ? ? Tayal et al. ? ? Squire et al. ? ? Page-Wills et al. ? § ? Quraishi et al. ? ? : Low Risk; §: High Risk; ?: Unclear Risk. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 8 Figure 1: Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flowchart of the literature search and selection of studies that reported accuracy of point-of-care ultrasonography for diagnosis of abscess. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 9 Archives of Academic Emergency Medicine. 2023; 11(1): e49 Figure 2: Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) flowchart of the literature search and selection of studies that reported accuracy of point-of-care ultrasonography for diagnosis of abscess. Figure 3: Forest plot of the pooled specificity of point-of-care ultrasonography for diagnosis of abscess. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 10 Figure 4: Forest plot of the pooled positive likelihood ratio (LR) of point-of-care ultrasonography for diagnosis of abscess. CI: confidence interval. Figure 5: Forest plot of the pooled negative likelihood ratio (LR) of point-of-care ultrasonography for diagnosis of abscess. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 11 Archives of Academic Emergency Medicine. 2023; 11(1): e49 Figure 6: Forest plot of the diagnostic odds ratio (OR) of point-of-care ultrasonography for diagnosis of abscess. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 12 Figure 7: Summary receiver-operating characteristic (SROC) curve of point-of-care ultrasonography for diagnosis of abscess. AUC: area under the curve. SE: standard error. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 13 Archives of Academic Emergency Medicine. 2023; 11(1): e49 Figure 8: Funnel plot of publication bias on the pooled diagnostic odds ratio of point-of-care ultrasonography for diagnosis of abscess. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index Introduction Methods Results Discussion Limitations Conclusion Declarations References