EVALUATION OF A RAPID ANTIGEN TEST FOR SARS-COV-2 IN SYMPTOMATIC PATIENTS AND THEIR CONTACTS: A MULTICENTER STUDY

BACKGROUND Point-of-care rapid tests to identify SARS-CoV-2 can be of great help because, in principle, they allow decisions to be made at the site of care for treatment, or for the separation of cohorts avoiding cross-infection, especially in emergency situations. METHODS A cross sectional study in adults requesting care in Emergency Rooms (ER), or the outpatient clinics of referral hospitals for COVID-19, to define the diagnostic characteristics of a rapid antigen test for SARS-CoV-2 (the Abbott PanbioTM) having as a gold standard the RT-PCR for SARS-CoV-2. Health personnel in a routine situation within an active pandemic in several cities of Mexico performed the tests. RESULTS A total of 1,069 participants with a mean age of 47 years (SD 16 years), 47% with a self-reported comorbidity, and an overall prevalence of a positive RT-PCR test of 45%, were recruited from eight hospitals in Mexico. Overall sensitivity of the Panbio test was 54.4% (95%CI 51-57) with a positive likelihood ratio of 35.7, a negative likelihood ratio of 0.46 and a Receiver-Operating Characteristics curve area of 0.77. Positivity for the rapid test depended strongly on an estimate of the viral load (Cycle threshold of RT-PCR, Ct), and the days of symptoms. With a Ct 25, sensitivity of the rapid test was 0.82 (95%CI, 0.76-0.87). For patients during the first week of symptoms sensitivity was 69.6% (95%CI 66-73). On the other hand, specificity of the rapid test was above 97.8% in all groups. CONCLUSIONS The PanbioTM rapid antigen test for SARS-CoV-2 has a good specificity, but due to low and heterogeneous sensitivity in real life, a negative test in a person with suggestive symptoms at a time of community transmission of SARS-CoV-2 requires confirmation with RT-PCR, and after the first week of symptoms, sensitivity decreases considerably.

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A20 DIAGNOSTIC ACCURACY OF A LOW COST, WIDELY AVAILABLE TEST STRIP FOR PREDICTING A POSITIVE FECAL CALPROTECTIN TEST

Journal of the Canadian Association of Gastroenterology ◽

10.1093/jcag/gwab002.019 ◽

2021 ◽

Vol 4 (Supplement_1) ◽

pp. 210-212

Author(s):

R Trasolini ◽

S Wong ◽

B Salh

Keyword(s):

Sample Size ◽

Likelihood Ratio ◽

Gold Standard ◽

Low Cost ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Rapid Test ◽

Test Strip ◽

Fecal Calprotectin ◽

Type I

Abstract Background Fecal calprotectin is a non-invasive test of colonic inflammation used for monitoring inflammatory bowel disease activity and for risk stratifying non-specific colonic symptoms. Calprotectin is a leukocyte specific enzyme. A similar test, leukocyte esterase is used to detect leukocytes in urine and is widely available as a low-cost point-of-care test strip. We hypothesize that an unmodified version of the urine test strip would be highly accurate in predicting a positive fecal calprotectin test in a real world sample of patients. Aims To explore a low cost, rapid alternative to the fecal calprotectin test Methods All inpatient and outpatient stool samples tested for calprotectin by the Vancouver General Hospital laboratory from February 2020 to November 2020 were included prospectively. Samples were simultaneously tested for fecal leukocyte esterase using an unmodified Roche Cobas Chemstrip urinalysis test strip by central lab personnel. An identical aliquot was sent to LifeLabs for calprotectin as per standard protocol. All samples were suspended in buffer using established laboratory protocols prior to testing. Fecal leukocyte esterase results were reported as 0–4+ based on visual interpretation, calprotectin results were reported as mcg/g of stool. REB review and approval was obtained prior to data collection. Sensitivity, Specificity and AUROC were calculated using Microsoft Excel and JROCFIT. Results 26 samples were collected. Using a fecal calprotectin greater than 120 mcg/g as a gold standard an AUROC of 0.89 (SE= .06) was calculated. A leukocyte esterase reading of 2+ or greater had the best test characteristics based on ROC curve analysis. Using this cutoff, 21/26 samples were concordant, giving an accuracy of 80.8%, sensitivity of 90.9% and specificity of 73.3%. Positive likelihood ratio was 8.07 and negative likelihood ratio was 0.29. Assuming an AUROC of 0.8, the sample size N=26 is 90% powered (β=0.9) to predict the true AUROC within 0.1 with a type I error rate of .05 (α<.05). Conclusions This study suggests application of a prepared stool sample to a urinalysis test strip gives a result highly predictive of a positive fecal calprotectin test. Further results are being collected prospectively to improve the robustness of these preliminary data. Secondary outcomes including comparison to endoscopy and biopsy results where available are planned if an adequate sample size can be accrued. Future studies justifying independent clinical use of leukocyte esterase would require a common gold standard comparator such as endoscopy. Fecal calprotectin testing is not universally insured and is not available as a rapid test strip. Use of fecal leukocyte esterase may reduce costs and shorten time to results if proven to be independently reliable. Funding Agencies None

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Diagnostic Test Validity of CT-Scan for Detection of Hepatocellular Carcinoma

Journal of National Institute of Neurosciences Bangladesh ◽

10.3329/jninb.v4i2.38929 ◽

2018 ◽

Vol 4 (2) ◽

pp. 133-136

Author(s):

Md Akter Hossain ◽

Md Saiful Haque ◽

Mostaque Ahmed Bhuiya ◽

Abu Bakar Siddique

Keyword(s):

Hepatocellular Carcinoma ◽

Ct Scan ◽

Likelihood Ratio ◽

Tertiary Care ◽

Test Validity ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Care Hospital ◽

Hepatocelluar Carcinoma ◽

Cross Sectional

Background: CT-scan can detect hepatocelluar carcinoma among the patients.Objective: The purpose of the present study was to see the pattern of hepatocelluar carcinoma among the patients attended at a tertiary care hospital in Dhaka city.Methodology: This cross-sectional study was carried out in the Department of Radiology and Imaging at Dhaka Medical College, Dhaka and Banghabandhu Sheikh Mujib Medical University, Dhaka from January 2007 to May 2008 for a period of around one and half year. All the patients presented with hepatocellular carcinoma at the age group of more than 20 years with both sexes were selected as study population. The patients were undergone CT-scan examination and the confirmation of tumor was performed by histopathological examination.Result: A total number of 50 patients were recruited in this study after fulfilling the inclusion and exclusion criteria. The sensitivity, specificity and accuracy of CT-scan in detecting hepatocellular carcinoma was seen to be 66%, 92% and 72% respectively. The PPV and NPV were 96.15% (95% CI 79.06% to 99.40%) and 45.83% (95% CI 34.53% to 57.58%) respectively. However, the Positive Likelihood Ratio and Negative Likelihood Ratio were 7.89 (95% CI 1.19 to 52.28) and 0.37(95% CI 0.23 to 0.60).Conclusion: In conclusion CT-scan is a good diagnostic tool for the detection of hepatocellular carcinoma.Journal of National Institute of Neurosciences Bangladesh, 2018;4(2): 133-136

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Validity and Diagnostic Accuracy of Clarke's Angle in Determining Paediatric Flexible Flatfoot Using Radiographic Findings as a Criterion Standard Measure: A Cross-Sectional Study

Journal of the American Podiatric Medical Association ◽

10.7547/20-133 ◽

2021 ◽

Author(s):

Fatma Hegazy ◽

Emad Aboelnasr ◽

Amr A. Abdel-Aziem ◽

In-Ju Kim

Keyword(s):

Diagnostic Accuracy ◽

Likelihood Ratio ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Cross Sectional Study ◽

Cross Sectional ◽

Radiographic Findings ◽

Flexible Flatfoot ◽

Foot Posture ◽

Posttest Probability

Background: Clinical diagnosis of Paediatric flexible flatfoot is still a challenging issue for the healthcare professionals. Clarke's Angle (CA) is frequently used clinically for assessing foot posture; however there is still a debate about its validity and diagnostic accuracy in evaluation of static foot posture especially in Paediatric population with some previous studies supporting, while the others are refuting its validity. The current study aimed to investigate validity and diagnostic accuracy of CA using radiographic findings as a criterion standard measure to determine flexible flatfoot between ages of 6-18 years. Methods: A cross-sectional study conducted on 612 participants (1224 feet) with flexible flatfoot aged 6-18 years (12.36 {plus minus}3.39) was recruited. The clinical measures results were compared to the criterion standard radiographic measures and displayed on the receiver operating characteristic curve (ROC) and the area under ROC curve (AUC) was computed. Intra-rater reliability, sensitivity, specificity, predictive values, and likelihood ratios were calculated for CA. Fagan nomogram was used to detect the posttest probability. Results: Clarke's angle (CA) demonstrated higher intra-rater reliability (ICC=0.99). CA showed higher sensitivity (98.4%), specificity (98.8), positive predictive value (97.3), negative predictive value (99.3), positive likelihood ratio (84) and negative likelihood ratio (0.02). AUC was 0.98[95%CI= 0095-1.00]. The positive likelihood ratio (LR+) yielded a posttest probability of 97%, while the negative likelihood ratio (LR−) yielded a posttest probability of 0.02. Conclusions: CA is a valid with high diagnostic accuracy in diagnosis of flexible flatfoot between the ages of 6-18 years.

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Diagnostic Laboratory Tests for COVID-19 in US: Methodology and Performance

10.21203/rs.3.rs-43374/v1 ◽

2020 ◽

Author(s):

Mrigendra M. Bastola ◽

Craig Locatis ◽

Paul Fontelo

Keyword(s):

Likelihood Ratio ◽

Sensitivity And Specificity ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Small Sample ◽

Published Data ◽

Test Accuracy ◽

Rt Pcr ◽

Likelihood Ratios ◽

Predictive Values

Abstract Background: COVID-19 is a global pandemic caused by a new coronavirus strain. Innovative tests have been developed to diagnose and characterize the spread of COVID-19. Only a few studies have reported the diagnostic value of currently available tests. The diagnostic performance of the tests is a major concern after the recent resurgence in COVID-19. Methods: Published papers and FDA data on the currently available tests were used for analysis. Likelihood ratios, and predictive values of tests were computed. Only FDA approved tests were included. RT-PCR performance among different specimen types were also explored.Main results: All the published reports on the COVID-19 tests reported RT-PCR as the validation tool for their results. Not all available COVID-19 tests reported their sensitivity and specificity. Among the publications which reported, the positive likelihood ratio ranged between 0.15 to 0.88 and tests had high negative likelihood ratio (0.99). Conclusion: Although most recent publications showed high positive and negative likelihood ratios and high predictive values, the publications on test accuracy and validity have limited scope primarily due to their small sample size and insufficiencies in methodology and published data. Although most lab tests reported high sensitivity and specificity, false omission and false discovery rates were found notable in several COVID-19 lab tests. These results suggest need for caution on test results’ interpretation. Practitioners also need to integrate evidence that is evolving rapidly.

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Diagnostic performance of circulating cell-free DNA for hepatocellular carcinoma: a systematic review and meta-analysis

Biomarkers in Medicine ◽

10.2217/bmm-2020-0334 ◽

2021 ◽

Vol 15 (3) ◽

pp. 219-239

Author(s):

Jinmei Zhang ◽

Yuan Yuan ◽

Shuxia Gao ◽

Xue Zhao ◽

Hong Li

Keyword(s):

Likelihood Ratio ◽

Odds Ratio ◽

Diagnostic Performance ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Diagnostic Odds Ratio ◽

Receiver Operating Characteristics ◽

Operating Characteristics ◽

Free Dna ◽

Sensitivity Specificity

Background: We aimed to assess the diagnostic performance of circulating cell-free DNA (cfDNA) in hepatocellular carcinoma (HCC). Materials & methods: After a systematic literature search bivariate linear mixed models were used to integrate sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio. The area under receiver operating characteristics curves of the included studies was used to estimate the diagnostic value. Results: Thirty-eight articles enrolled in quantitative synthesis. In overall analysis the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and area under receiver operating characteristics curves for cfDNA in distinguishing HCC patients from healthy controls were 0.54, 0.90, 5.23, 0.51, 10.27 and 0.82, respectively. Conclusion: This study suggests that cfDNA has a promising diagnostic accuracy in detection of HCC.

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Diagnostic Accuracy of Monofilament Tests for Detecting Diabetic Peripheral Neuropathy: A Systematic Review and Meta-Analysis

Journal of Diabetes Research ◽

10.1155/2017/8787261 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12 ◽

Cited By ~ 12

Author(s):

Fengyi Wang ◽

Jiaqi Zhang ◽

Jiadan Yu ◽

Shaxin Liu ◽

Rengang Zhang ◽

...

Keyword(s):

Peripheral Neuropathy ◽

Diagnostic Accuracy ◽

Likelihood Ratio ◽

Diabetic Peripheral Neuropathy ◽

Meta Analysis ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Cochrane Library ◽

Operating Characteristics ◽

Qualitative Synthesis

Objective. To systematically evaluate the diagnostic accuracy of monofilament tests for detecting diabetic peripheral neuropathy. Methods. We searched EMBASE (OvidSP), MEDLINE (OvidSP), the Cochrane Library, and Web of Science to identify diagnostic accuracy trials of monofilament tests for detecting diabetic peripheral neuropathy. We used a hierarchical summary receiver operating characteristics (HSROC) model to conduct the meta-analysis of diagnostic accuracy of monofilament tests for detecting diabetic peripheral neuropathy. Results. A total of 19 comparative trials met the inclusion criteria and were part of the qualitative synthesis. Eight trials using nerve conduction studies as the reference standard were selected for the meta-analysis. The pooled sensitivity and specificity of monofilament tests for detecting diabetic peripheral neuropathy were 0.53 (95% confidence interval (CI) 0.32 to 0.74) and 0.88 (95% CI 0.78 to 0.94), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 4.56 (95% CI 2.93 to 7.10) and 0.53 (95% CI 0.35 to 0.81), respectively. Conclusions. Our review indicated that monofilament tests had limited sensitivity for screening diabetic peripheral neuropathy. The clinical use of the monofilament test in the evaluation of diabetic peripheral neuropathy cannot be encouraged based on currently available evidence.

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Spanish Validation of the GEPARD Questionnaire for the Detection of Psoriatic Arthritis in Argentinian Patients with Psoriasis

Dermatology ◽

10.1159/000495983 ◽

2019 ◽

Vol 235 (2) ◽

pp. 101-106

Author(s):

María Victoria Martire ◽

María Paula Girard Bosch ◽

Santiago Scarafia ◽

Vanesa Cosentino ◽

Maria Janina Tapia Moreira ◽

...

Keyword(s):

Psoriatic Arthritis ◽

Likelihood Ratio ◽

Diagnostic Tool ◽

Area Under The Curve ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Cross Sectional Study ◽

Cross Sectional ◽

Spanish Validation ◽

Previous Diagnosis

Background/Objective: Psoriatic arthritis (PsA) is preceded by psoriasis in approximately 80% of cases. Dermatologists are pivotal for early detection. It is important to have simple tools that allow the detection of PsA in patients with skin psoriasis. The aim of our study was to evaluate the performance of an adapted version of the GEPARD Questionnaire in Spanish in Argentinian patients with psoriasis. Methods: This is a cross-sectional study. A new Spanish (Argentinian) (GEPARDa) translated version of the original questionnaire (German) was developed and then tested as a diagnostic tool in patients with psoriasis, PsA, osteoarthritis associated to psoriasis, and osteoarthritis, all evaluated by rheumatologists who used the CASPAR criteria. Results: Eighty-three patients were included (55 [66.3%] women with a mean age of 50.7 years [SD 6.3]). Forty-four patients had PsA (29 [34.9%] patients had previous diagnosis of PsA, and 15 [18%] were newly diagnosed after referral by their dermatologists), and 39 patients were without PsA (18 [21.6%] patients had psoriasis without articular involvement, 6 [7.22%] had psoriasis associated with osteoarthritis, and 15 [18%] had osteoarthritis). An area under the curve of 0.9554 (SD 0.01; 95% CI 0.91–0.99) was calculated considering the CASPAR criteria as the gold standard. With a cutoff of ≥6 the questionnaire showed a sensitivity of 88.64%, a specificity of 89.74%, a positive likelihood ratio of 8.6, and a negative likelihood ratio of 0.12. Conclusions: The GEPARDa version has proven to be a diagnostic tool with excellent performance so that it can be considered a valid tool for the detection of PsA in Argentinian patients.

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Diagnostic Accuracy of Laser Doppler Imaging for the Assessment of Burn Depth: A Meta-analysis and Systematic Review

Journal of Burn Care & Research ◽

10.1093/jbcr/irz203 ◽

2019 ◽

Vol 41 (3) ◽

pp. 619-625 ◽

Cited By ~ 2

Author(s):

Ru Wang ◽

Juan Zhao ◽

Zhenyu Zhang ◽

Chang Cao ◽

Yange Zhang ◽

...

Keyword(s):

Likelihood Ratio ◽

Meta Analysis ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Laser Doppler ◽

Doppler Imaging ◽

Laser Doppler Imaging ◽

Summary Receiver Operating Characteristic ◽

Cross Sectional ◽

Burn Depth

Abstract An overall assessment of the diagnostic value of laser Doppler imaging (LDI) to assess burn depth in patients is presented based on relevant studies. Both eligible research and relevant articles were identified through specific index searches of Embase, Cochrane, and PubMed databases. The latest study included was published in March 2019 and all eligible publications reported on cohort or cross-sectional research. All articles were tested for heterogeneity by using a suitable effect model to calculate amalgamative values of sensitivity, specificity, and the diagnostic odds ratio (DOR). Analyses of summary receiver operating characteristic (SROC) are given for burn depth values. After rigorous screening, 14 studies with a total cohort of 1,818 patients were chosen for the meta-analysis to explore the validity of LDI diagnosis to assess the depth of burns. The burn depth overall sensitivity for LDI was 91% (95% CI: 86–95%) and global specificity was 96% (95% CI: 92–98%). The overall positive likelihood ratio of LDI was 20.35 (95% CI: 10.71–38.69) and the overall negative likelihood ratio was 0.09 (95% CI: 0.05–0.15). The overall DOR was 152.93 (95% CI: 69.44–336.81) of LDI. The acreage under the SROC was not low for LDI (AUC = 0.98; 95% CI: 0.96–0.99). In conclusion, the present analysis reviewed the literature and meta-analysis of studies to validate LDI for the diagnosis of burn depth. The results indicated that LDI has a high accuracy for this diagnostic function.

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Diagnostic Validity of Serum Cystatin C for Detection of Acute Kidney Injury in Children

Bangladesh Journal of Infectious Diseases ◽

10.3329/bjid.v7i2.51508 ◽

2021 ◽

Vol 7 (2) ◽

pp. 44-48

Author(s):

Sharmin Akter Luna ◽

Jakia Sultana ◽

Md Abdullah Yusuf ◽

Golam Muin Uddin ◽

Md Habibur Rahman ◽

...

Keyword(s):

Acute Kidney Injury ◽

Likelihood Ratio ◽

Cystatin C ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Kidney Injury ◽

Diagnostic Validity ◽

Serum Cystatin C ◽

Cross Sectional ◽

Serum Cystatin

Background: Detection of acute kidney injury is very essential among the children. Objective: The purpose of the present study was to validate the serum cystatin C for the detection of acute kidney injury in children. Methodology: This cross-sectional study was conducted in the Department of Paediatric Nephrology with the collaboration of Paediatric Gastroenterology, Paediatric Neurology, Paediatric Neonatology and Microbiology and Immunology at Bangabandhu Sheikh Mujib University, Dhaka, Bangladesh from May 2018 to July 2019 for a period of one year. Patients with the age group of 1 month to 17 years, who were at risk of AKI, and admitted in the inpatient department of Pediatrics and allied at Bangabandhu Sheikh Mujib University, Dhaka, Bangladesh during this study period in both sexes were selected as study population. To detect AKI, serum creatinine was measured at 0 h (baseline), 48 h and 5th day respectively. Serum cystatin C were measured at 0 (baseline) and 48 h respectively for all patients. Result: A total number of 52 patients were enrolled in this study. Here the AUC was 0.93 with 95% CI (0.864 - 0.995). Serum cystatin C had sensitivity of 95% (95% CI 77.9%-099.7%) with specificity 84% (95% CI 73.7%-87.3%), PPV 79% (95% CI 64.9%-83.1%), NPV 96% (95% CI 84.2%-99.8%), accuracy 88.7% (95% CI 75.3%-92.1%), positive likelihood ratio 6.08 and negative likelihood ratio 0.06 (95% CI 2.96-7.87 and 0.003-0.300 respectively). Conclusion: In conclusion the diagnostic validity of serum cystatin C for the detection of AKI is very high among the children. Bangladesh Journal of Infectious Diseases 2020;7(2):44-48

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Evaluation of the diagnostic accuracy of a hemoglobin S and C screening test: Sickle Scan

International Journal of Biological and Chemical Sciences ◽

10.4314/ijbcs.v15i1.20 ◽

2021 ◽

Vol 15 (1) ◽

pp. 234-240

Author(s):

L. Adjé ◽

V. Yapo ◽

M. Yayo-Ayé ◽

S. Bognini ◽

M. Meledje ◽

...

Keyword(s):

Likelihood Ratio ◽

Screening Tool ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Reference Method ◽

Cross Sectional Study ◽

Cross Sectional ◽

Hemoglobin S ◽

Hemoglobin C ◽

Sensitivity Specificity

New tools for the rapid diagnosis of hemoglobinosis could encourage the extension of their screening in Africa. Our goal was to assess the analytical performances of a rapid hemoglobin S and C detection test, the Sickle Scan. This was a cross-sectional study carried out in March 2019 at the Yopougon Teaching Hospital. The subjects followed for hemoglobinosis as well as the subjects seeking out an electrophoresis of their hemoglobin were included. We carried out the hemogram, the electrophoresis of hemoglobin at alkaline pH (reference method) coupled with the metabisulfite sickling test (Emmel test) and the rapid detection test to be evaluated. This immunochromatographic test is capable of detecting hemoglobins A, S, and C, and to infer the hemoglobin phenotype from there. The study recruited 191 individuals. The test detected hemoglobins S and C with a sensitivity of 99.4% and 97.7% respectively; a specificity of 93.3% and 99.3%. The positive likelihood ratio for hemoglobins S and C was 15 and 144 respectively. The negative likelihood ratio was 0.01 for hemoglobin S, and 0.02 for hemoglobin C. The intrinsic characteristics obtained make this test an interesting screening tool for hemoglobinosis S and C. Keywords: Diagnostic test, hemoglobinosis, Abidjan, sensitivity, specificity.

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