Clinical validation of point-of-care SARS-COV-2 BD Veritor antigen test by a single throat swab for rapid COVID-19 status on hospital patients predominantly without overt COVID symptoms

AbstractBACKGROUNDFast identification of severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) infected individuals is a strategically vital task to ensure correct management and quarantine. Rapid antigen test could be a supplement to the standard-of-care Nucleic Acid Amplification Test (NAAT). The aim of this study was to determine the accuracy of the BD Veritor SARS-CoV-2 antigen test as a screening instrument in a hospital setting.METHODSA cohort of prospective samples were collected from hospital staff and patients at the Emergency, Infectious Diseases and Pediatrics and Adolescent Medicine departments at Hvidovre Hospital. All samples were collected using oropharyngeal swabs, and BD Veritor Antigen test results were paired with routine NAAT test results. Sensitivity, specificity, positive and negative predictive values of the antigen test were calculated using NAAT as reference.RESULTSOverall, 809 samples from 674 individuals were included (average age 45 years, range 0-98 years). Among all samples, 8% were SARS-CoV-2 positive by NAAT testing and 5.3% by BD Veritor. The sensitivity of the antigen test was 63.1% and specificity 99.7%. The positive predictive value was 95.3%. False-positive rate was 4%. The cycle threshold value was significantly higher among individuals with false negative antigen tests compared to true positives.CONCLUSIONThe sensitivity, specificity and positive predictive values show that the BD Veritor antigen test from oropharyngeal collected specimens performs well. Antigen testing may be a supplement, but not substitute, to NAAT testing as the primary diagnostic modality in hospital settings where fast turnaround test results may assist in decisions regarding isolation and quarantine.

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Detection of SARS-CoV-2 infection by rapid antigen test in comparison with RT-PCR in a public setting

10.1101/2021.01.22.21250042 ◽

2021 ◽

Cited By ~ 1

Author(s):

Kathrine Kronberg Jakobsen ◽

Jakob Schmidt Jensen ◽

Tobias Todsen ◽

Freddy Lippert ◽

Cyril Jean-Marie Martel ◽

...

Keyword(s):

False Negative ◽

Pcr Analysis ◽

Nasopharyngeal Swab ◽

Test Results ◽

Antigen Test ◽

Rt Pcr ◽

Predictive Values ◽

Public Setting ◽

Antigen Tests ◽

Sensitivity Specificity

AbstractBackgroundRapid and accurate detection of SARS-CoV-2 infection is essential in limiting the spread of infection during the ongoing COVID-19 pandemic. The aim of this study was to determine the accuracy of the STANDARD Q COVID-19 Ag test (SD BIOSENSOR) by comparison with RT-PCR in a public setting.MethodIndividuals aged 18 years or older who had booked an appointment for a RT-PCR test on December 26-31, 2020 at a public test center in Copenhagen, Denmark, were invited to participate. An oropharyngeal swab was collected for RT-PCR analysis, immediately followed by a nasopharyngeal swab examined by the STANDARD Q COVID-19 Ag test (SD BIOSENSOR). Sensitivity, specificity, positive and negative predictive values of the antigen test were calculated with test results from RT-PCR as reference.ResultsOverall, 4697 individuals were included (female n=2456, 53.3%; mean age: 44.7 years, SD: 16.9 years); 196 individuals were tested twice or more. Among 4811 paired conclusive test results from the RT-PCR and antigen tests, 221 (4.6%) RT-PCR tests were positive. The overall sensitivity and specificity of the antigen test were 69.7% and 99.5%, the positive and negative predictive values were 87.0% and 98.5%. Ct values were significantly higher among individuals with false negative antigen tests compared to true positives.ConclusionThe sensitivity, specificity, and predictive values found indicate that the STANDARD Q COVID-19 Ag is a good supplement to RT-PCR testing.

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Validation of a rapid antigen test as a screening tool for SARS-CoV-2 infection in asymptomatic populations. Sensitivity, specificity and predictive values

EClinicalMedicine ◽

10.1016/j.eclinm.2021.100954 ◽

2021 ◽

pp. 100954

Author(s):

Alejandro Fernandez-Montero ◽

Josepmaria Argemi ◽

José Antonio Rodríguez ◽

Arturo H. Ariño ◽

Laura Moreno-Galarraga

Keyword(s):

Screening Tool ◽

Antigen Test ◽

Predictive Values ◽

Sensitivity Specificity

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Evaluation of optimal urine screening and confirmation cut-off values for opiates, at a national reference laboratory

Turkish Journal of Biochemistry ◽

10.1515/tjb-2020-0614 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Çiğdem Karakükcü ◽

Mehmet Zahid Çıracı ◽

Derya Kocer ◽

Mine Yüce Faydalı ◽

Muhittin Abdulkadir Serdar

Keyword(s):

False Positive ◽

False Positive Rate ◽

False Negative ◽

Urine Samples ◽

Reference Laboratory ◽

National Reference Laboratory ◽

Urine Screening ◽

National Reference ◽

Positive Rate ◽

Sensitivity Specificity

Abstract Objectives To obtain optimal immunoassay screening and LC-MS/MS confirmation cut-offs for opiate group tests to reduce false positive (FP) and false negative (FN) rates. Methods A total of 126 urine samples, −50 opiate screening negative, 76 positive according to the threshold of 300 ng/mL by CEDIA method – were confirmed by a full-validated in-house LC-MS/MS method. Sensitivity, specificity, FP, and FN rates were determined at cut-off concentrations of both 300 and 2,000 ng/mL for morphine and codeine, and 10 ng/mL for heroin metabolite 6-mono-acetyl-morphine (6-MAM). Results All CEDIA opiate negative urine samples were negative for morphine, codeine and 6-MAM. Although sensitivity was 100% for each cut-off; specificity was 54.9% at CEDIA cut-off 300 ng/mL vs. LC-MS/MS cut-off 300 ng/mL and, 75% at CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 2,000 ng/mL. False positive rate was highest (45.1%) at CEDIA cut-off 300 ng/mL. At CEDIA cut-off 2,000 ng/mL vs. LC-MS/MS cut-off 300 ng/mL, specificity increased to 82.4% and FP rate decreased to 17.6%. All 6-MAM positive samples had CEDIA concentration ≥2,000 ng/mL. Conclusions 2,000 ng/mL for screening and 300 ng/mL for confirmation cut-offs are the most efficient thresholds for the lowest rate of FP opiate results.

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THE ROLE OF ULTRASONOGRAPHY IN THE DETECTION OF UROLITHIASIS IN PATIENTS WITH ACUTE RENAL COLIC

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v4i7.1320 ◽

2020 ◽

Vol 4 (6) ◽

Author(s):

Sanjay Narayangiri Gosavi ◽

Virendra K Meena ◽

Ayush Tambi

Keyword(s):

Ct Scan ◽

Renal Colic ◽

False Negative ◽

Helical Ct ◽

Urinary Stones ◽

Predictive Values ◽

Acute Renal Colic ◽

Mean Size ◽

Acute Flank Pain ◽

Sensitivity Specificity

This study was conducted to assess the diagnostic Ultrasonography compared to unenhanced helical CT scan in detecting urinary stones in patients with acute renal colic. This retrospective study comprised of 156 patients who undergo unenhanced urinary tract CT scan and ultrasonography for thought of urolithiasis. Both techniques were used to resolve the presence or absence, site, size, and number of urinary stones, as well as company of any other intra-abdominal pathology. For statistical analysis, the sensitivity, specificity, predictive values, and diagnostic accuracy of ultrasonography were deliberate considering unenhanced CT scan as a gold normal. Unpaired two-tailed student’s t-test was used for judgment between mean size of true positive, false positive, and false negative stones. There were 68 patients having 115 urinary stones. Ultrasound identified 54 stones, missed 43, and falsely diagnosed 18 stones. The mean size of true positive, false positive, and false negative stones were 4.8 ± 3.3 mm, 6 ± 1.8 mm and 4.18 ± 3 mm, respectively. There were 23 patients with other intra-abdominal pathologies, equally detected by both techniques. Ultrasound helped in identifying the cause of acute flank pain in 62% of cases. The overall sensitivity, specificity, positive and negative predictive values, and correctness of ultrasonography in the diagnosis of renal stone disease were 58%, 91%, 79%, 78%, and 78%, respectively. Our study suggests that, despite its limited value in detecting urinary stones, ultrasonography should be performed as an initial assessment in patients with acute flank pain. Unenhanced helical CT should be reserved for patients in whom ultrasonography is uncertain. Keywords: Ultrasonography, CT scan

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Role of Covid Antigen in the Diagnosis of Covid Positive in Obstetric Patients

10.53350/pjmhs2115103356 ◽

2021 ◽

Vol 15 (10) ◽

pp. 3356-3358

Author(s):

Ambreen Fatima ◽

Nidda Yaseen ◽

Amna Fareed ◽

Kashif Ali Samin ◽

Shumaela Kanwal ◽

...

Keyword(s):

Nucleic Acid ◽

Early Detection ◽

Negative Predictive Value ◽

Predictive Value ◽

False Negative ◽

Nucleic Acid Amplification ◽

Antigen Test ◽

Rt Pcr ◽

Cross Sectional ◽

Specificity And Sensitivity

Background and Aim: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid emergence postured significant challenges on the health system in recent years. The early detection of cases is thought to be critical in preventing this pandemic by coronavirus disease (COVID-19), especially important in the obstetrical population due to theirs numerous interactions with another parturient when hospitalized for delivery. Therefore, the present study aimed to assess the COVID antigen test performance in COVID-positive obstetrics patients. Materials and Methods: This cross-sectional study was conducted on 1296 Covid-19 asymptomatic women admitted to the Obstetrics and Gynaecology Department of Muhammad Teaching Hospital & Medical College, Peshawar and Fauji Foundation Hospital, Rawalpindi for the duration of six months from February 2021 to July 2021. Antigen-based test rapid diagnostic test (RDT) was used for screening out COVID-19 positive obstetrics patients or women through nasopharyngeal swabs. Women with negative rapid antigen test results were confirmed with RT-polymers chain reaction test of nucleic acid amplification tests (NAAT). Ethical approval and informed consent were taken from the hospital ethical committee and each individual respectively. All the known positive COVID-19 patients during admission were excluded. SPSS version 24 was used for data analysis. Results: The overall prevalence of rapid antigen-positive tested patients was 13.2% (171/1296). The prevalence of positive tested women through rapid antigen test, Nucleic Acid Amplification Test (NAAT), and RT-PCR were 27 (2.1%), 51 (3.9%), and 93 (7.2%) respectively. Of the total 1296 rapid antigen tests, 27 were positive, and the false-negative confirmed positive by NAAT was 144.Thus the sensitivity of the rapid antigen test was 15.8% and the negative predictive value was 93.7%. Of the total 298 Nucleic Acid Amplification Tested had sensitivity and negative predictive value of 89.6% and 99.06% respectively. RT-PCR was carried out on 972 patients, positive diagnosed cases were 36 while 15 were initially negative and were positive with the test was repeated. The sensitivity and negative predictive value was 71.45% and 95.8% respectively. Conclusion: Our study found that Ag-RDT plays a significant role in SARS-CoV-2 early detection in infected individuals, with high specificity and sensitivity to disease infectious stage, whether symptomatic or asymptomatic, and can be used as a decision supported tool. Early detection of COVID-19 status in women admitted for delivery could benefit neonatal protection care. Keywords: Covid-19; Rapid antigen test; RT-PCR test

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A Study of the Diagnostic Accuracy of an Existing Multivariable Test to Predict Shoulder Dystocia

American Journal of Perinatology Reports ◽

10.1055/s-0039-1693162 ◽

2019 ◽

Vol 09 (03) ◽

pp. e262-e267

Author(s):

Henry Alexander Easley ◽

Todd Michael Beste

Keyword(s):

Diagnostic Accuracy ◽

Prediction Model ◽

Study Design ◽

False Positive ◽

False Positive Rate ◽

Shoulder Dystocia ◽

The Other ◽

Predictive Values ◽

Positive Rate ◽

Sensitivity Specificity

Objectives To evaluate the diagnostic accuracy of a multivariable prediction model, the Shoulder Screen (Perigen, Inc.), and compare it with the American College of Obstetricians and Gynecologists (ACOG) guidelines to prevent harm from shoulder dystocia. Study Design The model was applied to two groups of 199 patients each who delivered during a 4-year period. One group experienced shoulder dystocia and the other group delivered without shoulder dystocia. The model's accuracy was analyzed. The performance of the model was compared with the ACOG guideline. Results The sensitivity, specificity, positive, and negative predictive values of the model were 23.1, 99.5, 97.9, and 56.4%, respectively. The sensitivity of the ACOG guideline was 10.1%. The false-positive rate of the model was 0.5%. The accuracy of the model was 61.3%. Conclusion A multivariable prediction model can predict shoulder dystocia and is more accurate than ACOG guidelines.

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An assessment of chromosomal alterations detected by fluorescence in situ hybridisation in pancreatobiliary tract malignancy

BMC Gastroenterology ◽

10.1186/s12876-020-01439-0 ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Xiaohong Pu ◽

Hongwei Zheng ◽

Xin Yang ◽

Qing Ye ◽

Zhiwen Fan ◽

...

Keyword(s):

Predictive Value ◽

In Situ Hybridisation ◽

False Negative ◽

Chinese Patients ◽

Fluorescence In Situ Hybridisation ◽

Predictive Values ◽

Formalin Fixed Paraffin Embedded ◽

9P21 Locus ◽

Sensitivity Specificity

Abstract Background Using fluorescence in situ hybridisation (FISH) to detect any gain of chromosomes 3, 7, or 17 and loss of the 9p21 locus has been proven to be sensitive in the diagnosis of pancreatobiliary tumors. However, both genetic and environmental factors contribute to the pathogenesis of pancreatobiliary tumors. Therefore, it is unknown whether this method is suitable for Chinese patients with pancreatobiliary tumors. This study aims to compare the sensitivity, specificity, predictive values and accuracy of cytology, ERCP/MRCP and FISH based on Chinese patients with pancreatobiliary tumors,and to analyze differences between brushing-based and formalin-fixed paraffin-embedded (FFPE)-based FISH. Methods A total of 66 brush cytology specimens obtained during ERCP were detected by FISH and cytology test respectively to compare the sensitivity, specificity, predictive values and accuracy. Besides, FFPE-based FISH was performed on 46 corresponding paraffin sections of pancreatobiliary tumors obtained by surgical resection. Results Our findings demonstrate that FISH greatly improves diagnostic sensitivity and negative predictive value compared to ERCP/MRCP and cytology without much reduction in specificity and positive predictive value. However, our results also indicate that FFPE-based FISH could not effectively identify the false-negative of brushing-based FISH. Conclusions We believe that FISH can effectively distinguish true positive and false positive results of cytological or radiological suspicions of malignancy. However, FFPE-based FISH still does not precisely recognize the false-negative of brushing-based FISH. Both cytology-based and PPFE-based FISH had limitation in some specimens.

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Accuracy of ICD-9 coding for Clostridium difficile infections: a retrospective cohort

Epidemiology and Infection ◽

10.1017/s0950268806007655 ◽

2006 ◽

Vol 135 (6) ◽

pp. 1010-1013 ◽

Cited By ~ 82

Author(s):

D. B. SCHEURER ◽

L. S. HICKS ◽

E. F. COOK ◽

J. L. SCHNIPPER

Keyword(s):

Clostridium Difficile ◽

Administrative Data ◽

Epidemiological Surveillance ◽

Administrative Database ◽

Test Results ◽

Micro Data ◽

Cytotoxic Assay ◽

Predictive Values ◽

Sensitivity Specificity ◽

Microbiological Data

SUMMARYClostridium difficile (C. diff) is a major nosocomial problem. Epidemiological surveillance of the disease can be accomplished by microbiological or administrative data. Microbiological tracking is problematic since it does not always translate into clinical disease, and it is not always available. Tracking by administrative data is attractive, but ICD-9 code accuracy for C. diff is unknown. By using a large administrative database of hospitalized patients with C. diff (by ICD-9 code or cytotoxic assay), this study found that the sensitivity, specificity, positive, and negative predictive values of ICD-9 coding were 71%, 99%, 87%, and 96% respectively (using micro data as the gold standard). When only using symptomatic patients the sensitivity increased to 82% and when only using symptomatic patients whose test results were available at discharge, the sensitivity increased to 88%. C. diff ICD-9 codes closely approximate true C. diff infection, especially in symptomatic patients whose test results are available at the time of discharge, and can therefore be used as a reasonable alternative to microbiological data for tracking purposes.

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Liquid-Based Cytology in Diagnosing Nasopharyngeal Carcinoma

American Journal of Rhinology and Allergy ◽

10.2500/ajra.2009.23.3341 ◽

2009 ◽

Vol 23 (4) ◽

pp. 422-425 ◽

Cited By ~ 6

Author(s):

Yee-Jee Jan ◽

Su-Ju Chen ◽

John Wang ◽

Rong-San Jiang

Keyword(s):

Nasopharyngeal Carcinoma ◽

False Positive Rate ◽

False Negative ◽

False Negative Rate ◽

Sampling Technique ◽

Punch Biopsy ◽

Great Success ◽

Nasopharyngeal Biopsy ◽

Liquid Based Cytology ◽

Sensitivity Specificity

Background Liquid-based cytology (LBC) has achieved great success in cytological diagnosis of various cancers when compared with conventional smear methods. However, its application in diagnosing nasopharyngeal carcinoma (NPC) has never been studied. Methods Eighty-four consecutive patients who underwent nasopharyngeal biopsy for suspicious NPC or a nasopharyngeal mass under nasopharyngoscopy were enrolled in this prospective study. Brush samples were taken from the same site before punch biopsy and processed with the Thin Prep test. Results The adequacy, accuracy, sensitivity, specificity, false-negative rate, and false-positive rate of LBC in diagnosing NPC were 92.9% (78 of 84), 93.6% (73 of 78), 84.2% (16 of 19), 96.6% (57 of 59), 15.8% (three of 19), and 3.4% (two of 25), respectively. There were four inadequate specimens from patients with NPC and two inadequate ones from those without NPC. Conclusions Our study showed that the adequacy, accuracy, sensitivity, specificity, and diagnostic rate of LBC were equivalent to those using conventional smear methods. Although the diagnostic rate of NPC was lower using brush cytology than by punch biopsy, further improvements in the sampling technique could make brushing cytology a potential tool for NPC screening.

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False positive antigen test for Dirofilaria immitis after heat treatment of the blood sample in a microfilaremic dog infected with Acanthocheilonema dracunculoides

Parasites & Vectors ◽

10.1186/s13071-020-04376-9 ◽

2020 ◽

Vol 13 (1) ◽

Author(s):

Viktor Szatmári ◽

Martin Willem van Leeuwen ◽

Christine Jantine Piek ◽

Luigi Venco

Keyword(s):

Heat Treatment ◽

Blood Sample ◽

Real Time ◽

Real Time Pcr ◽

False Positive ◽

Dirofilaria Immitis ◽

False Negative ◽

Correct Identification ◽

Test Results ◽

Antigen Test

Abstract Background Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott’s test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides). Results A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott’s tests one month after the last treatment. Conclusions We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides.

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