Validation of equine influenza real time RT‐PCR test to OIE standard

Recently, an argument was put forth because a symptomatic and positive patient for CoVID-19 turned tested negative after 7 days, so discharged from the hospital. Both at the time of admission and discharge real-time reverse transcriptase Polymerase Chain Reaction (RT-PCR) was done for testing of CoVID-19. Immediately, patient again developed respiratory symptoms and was admitted to hospital again. Amidst of current CoVID-19 pandemic, a question was asked “What is the specificity of the Real Time-Polymerase Chain Reaction (RT-PCR) test for COVID-19?” with an assumption that what if at the time of discharge the disease is present in patient but test turned out to be negative? In response to that a counter statement was posed that “It is the sensitivity that should be asked rather than specificity”. It was based on the implication of primary question that was implying false negative report of the RT-PCR. It means, since patient was discharged with negative result that could be false negative.

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Reducing False Negative PCR Test for COVID-19

International Journal of MCH and AIDS (IJMA) ◽

10.21106/ijma.421 ◽

2020 ◽

Vol 9 (3) ◽

pp. 408-410

Author(s):

Fatemeh Bahreini ◽

Rezvan Najafi ◽

Razieh Amini ◽

Salman Khazaei ◽

Saeid Bashirian

Keyword(s):

Polymerase Chain Reaction ◽

Real Time ◽

False Negative ◽

Rt Pcr ◽

Chain Reaction ◽

Creative Commons ◽

Negative Results ◽

False Negative Results ◽

Polymerase Chain ◽

Pcr Test

As the SARS-CoV-2 (COVID-19) pandemic spreads rapidly, there is need for a diagnostic test with high accuracy to detect infected individuals especially those without symptoms. Real-time polymerase chain reaction (RT-PCR) is a common molecular test for diagnosing SARS-CoV-2. If some factors are not taken into consideration when performing this test, it can have a relatively large number of false negative results. In this article, we discuss important considerations that could lead to false negative test reduction. Key words: • SARS-CoV-2 • COVID-19 • Real time polymerase chain reaction • RT-PCR test • Diagnosis • False negatives • Genetics • Emerging disease Copyright © 2020 Bahreini et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0)which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in this journal, is properly cited.

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Development and validation of a real-time RT-PCR test for screening pepper and tomato seed lots for the presence of pospiviroids

PLoS ONE ◽

10.1371/journal.pone.0232502 ◽

2020 ◽

Vol 15 (9) ◽

pp. e0232502

Author(s):

Marleen Botermans ◽

Johanna W. Roenhorst ◽

Marinus Hooftman ◽

Jacobus Th. J. Verhoeven ◽

Eveline Metz ◽

...

Keyword(s):

Real Time ◽

Rt Pcr ◽

Tomato Seed ◽

Development And Validation ◽

Pcr Test

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Development and validation of a real-time RT-PCR test for screening pepper and tomato seed lots for the presence of pospiviroids

10.1101/2020.04.17.046508 ◽

2020 ◽

Author(s):

Marleen Botermans ◽

Johanna W. Roenhorst ◽

Marinus Hooftman ◽

Jacobus Th.J. Verhoeven ◽

Eveline Metz ◽

...

Keyword(s):

Real Time ◽

Seed Transmission ◽

Potato Spindle Tuber Viroid ◽

Rt Pcr ◽

Tomato Seed ◽

Stunt Viroid ◽

Testing Laboratories ◽

Tomato Chlorotic Dwarf Viroid ◽

Development And Validation ◽

Pcr Test

AbstractPotato spindle tuber viroid and other pospiviroids can cause serious diseases in potato and tomato crops. Consequently, pospiviroids are regulated in several countries. Since seed transmission is considered as a pathway for the introduction and spread of pospiviroids, some countries demand for the testing of seed lots of solanaceous crops for the presence of pospiviroids. A real-time RT-PCR test, named PospiSense, was developed for testing pepper (Capsicum annuum) and tomato (Solanum lycopersicum) seeds for seven pospiviroid species known to occur naturally in these crops. The test consists of two multiplex reactions running in parallel, PospiSense 1 and PospiSense 2, that target Citrus exocortis viroid (CEVd), Columnea latent viroid (CLVd), pepper chat fruit viroid (PCFVd), potato spindle tuber viroid (PSTVd), tomato apical stunt viroid (TASVd), tomato chlorotic dwarf viroid (TCDVd) and tomato planta macho viroid (TPMVd, including the former Mexican papita viroid). Dahlia latent viroid (DLVd) is used as an internal isolation control. Validation of the test showed that for both pepper and tomato seeds the current requirements of a routine screening test are fulfilled, i.e. the ability to detect one infested seed in a sample of c.1000 seeds for each of these seven pospiviroids. Additionally, the Pospisense test performed well in an inter-laboratory comparison, which included two routine seed-testing laboratories, and as such provides a relatively easy alternative to the currently used tests.

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Diagnostic value of Chest CT and Initial Real-Time RT-PCR in COVID-19 Infection

Pakistan Journal of Medical Sciences ◽

10.12669/pjms.37.1.2956 ◽

2020 ◽

Vol 37 (1) ◽

Author(s):

Ugur Kostakoglu ◽

Aydın Kant ◽

Serhat Atalar ◽

Barış Ertunç ◽

Şükrü Erensoy ◽

...

Keyword(s):

Real Time ◽

Diagnostic Value ◽

Chest Ct ◽

Symptom Duration ◽

Shortness Of Breath ◽

Rt Pcr ◽

Ct Findings ◽

Group I ◽

Group Ii ◽

Pcr Test

Objectives: To evaluate the diagnostic value of the rtRT-PCR test and CT in patients presenting with typical clinical symptoms of COVID-19. Methods: The study with the participation of four center in Turkey was performed retrospectively from 20 March-15 April 2020 in 203 patients confirmed for COVID-19. The initial rtRT-PCR test was positive in 142 (70.0%) of the patients (Group-I) and negative in 61 patients (Group-II). Results: The mean age of the patients in Group-I was 49.7±18.0 years and the time between the onset of symptoms and admission to the hospital was 3.6±2.0 days; whereas the same values for the patients in Group-II were 58.1±19.9 and 5.3±4.2, respectively (p=0.004; p=0.026). Initial rtRT-PCR was found positive with 83.5% sensitivity and 74.1% PPV in patients with symptom duration of less than five days. It was found that rtRT-PCR positivity correlated negatively with the presence of CT findings, age, comorbidity, shortness of breath, and symptom duration, while rtRT-PCR positivity correlated positively with headache. Presence of CT findings was positively correlated with age, comorbidity, shortness of breath, fever, and the symptom duration. Conclusions: It should be noted that a negative result in the rtRT-PCR test does not rule out the possibility of COVID-19 diagnosis in patients whose symptom duration is longer than five days, who are elderly with comorbidities and in particular who present with fever and shortness of breath. In these patients, typical CT findings are diagnostic for COVID-19. A normal chest CT is no reason to loosen up measures of isolation in patients with newly beginning symptoms until the results are obtained from the PCR test. doi: https://doi.org/10.12669/pjms.37.1.2956 How to cite this:Kostakoglu U, Kant A, Atalar S, Ertunc B, Erensoy S, Dalmanoglu E, et al. Diagnostic value of Chest CT and Initial Real-Time RT-PCR in COVID-19 Infection. Pak J Med Sci. 2021;37(1):-234-238. doi: https://doi.org/10.12669/pjms.37.1.2956 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Rapid SARS-CoV-2 antigen detection assay in comparison with real-time RT-PCR assay for laboratory diagnosis of COVID-19 in Thailand

Virology Journal ◽

10.1186/s12985-020-01452-5 ◽

2020 ◽

Vol 17 (1) ◽

Cited By ~ 3

Author(s):

Chutikarn Chaimayo ◽

Bualan Kaewnaphan ◽

Nattaya Tanlieng ◽

Niracha Athipanyasilp ◽

Rujipas Sirijatuphat ◽

...

Keyword(s):

Real Time ◽

Sensitivity And Specificity ◽

False Negative ◽

Laboratory Diagnosis ◽

Antigen Detection ◽

Rt Pcr ◽

Pcr Assay ◽

Screening Assay ◽

The Real ◽

Pcr Test

Abstract Background The Coronavirus disease 2019 (COVID-19) pandemic continues to spread across the world. Hence, there is an urgent need for rapid, simple, and accurate tests to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Performance characteristics of the rapid SARS-CoV-2 antigen detection test should be evaluated and compared with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) test for diagnosis of COVID-19 cases. Methods The rapid SARS-CoV-2 antigen detection test, Standard™ Q COVID-19 Ag kit (SD Biosensor®, Republic of Korea), was compared with the real-time RT-PCR test, Allplex™ 2019-nCoV Assay (Seegene®, Korea) for detection of SARS-CoV-2 in respiratory specimens. Four hundred fifty-four respiratory samples (mainly nasopharyngeal and throat swabs) were obtained from COVID-19 suspected cases and contact individuals, including pre-operative patients at Siriraj Hospital, Bangkok, Thailand during March–May 2020. Results Of 454 respiratory samples, 60 (13.2%) were positive, and 394 (86.8%) were negative for SARS-CoV-2 RNA by real-time RT-PCR assay. The duration from onset to laboratory test in COVID-19 suspected cases and contact individuals ranged from 0 to 14 days with a median of 3 days. The rapid SARS-CoV-2 antigen detection test’s sensitivity and specificity were 98.33% (95% CI, 91.06–99.96%) and 98.73% (95% CI, 97.06–99.59%), respectively. One false negative test result was from a sample with a high real-time RT-PCR cycle threshold (Ct), while five false positive test results were from specimens of pre-operative patients. Conclusions The rapid assay for SARS-CoV-2 antigen detection showed comparable sensitivity and specificity with the real-time RT-PCR assay. Thus, there is a potential use of this rapid and simple SARS-CoV-2 antigen detection test as a screening assay.

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Development of a BCR/ABL Real-Time Quantitative RT-PCR Assay and Correlation with an Existing Qualitative Test.

Blood ◽

10.1182/blood.v106.11.4879.4879 ◽

2005 ◽

Vol 106 (11) ◽

pp. 4879-4879

Author(s):

John Greg Howe ◽

Jill Crouch ◽

Brian R. Smith

Keyword(s):

Real Time ◽

Rt Pcr ◽

Pcr Assay ◽

Quantitative Test ◽

Negative Results ◽

Test Strategies ◽

Qualitative Test ◽

Labeled Probe ◽

Multiple Samples ◽

Pcr Test

Abstract Introduction: With the recent introduction of imatinib (Gleevec) as a therapeutic agent for chronic myeloid leukemia (CML), the need for quantitation of the level of tumor cells after treatment has become essential. Our lab has for a number years tested for CML using a sensitive qualitative nested RT-PCR assay for BCR/ABL. We wanted to develop a quantitative test that retained the sensitivity of our qualitative test and contained an initial screen to prevent unnecessary quantitative testing as well as develop quantitative tests for the various breakpoints. Methods: The new test is divided into three parts. A real-time multiplex qualitative RT-PCR screen containing specific primers for the p190, p210 and p230 BCR/ABL forms and a common labeled probe. If a patient sample is positive in the screen, the original nested RT-PCR test is performed to determine which BCR/ABL form is present. This is followed by a real-time quantitative RT-PCR test for the identified BCR/ABL translocation. Subsequent follow up tests require only the specific quantitative test. Results: Comparing negative results from 82 patient (various clinical presentations) samples tested by the previous qualitative test with the new qualitative screen showed completely correlation. Out of 31 CML patients studied, both test strategies gave the same result for 20 positive and 13 negative samples. Patients with multiple samples collected over time showed complete correlation between the two assays. Conclusions: The new quantitative BCR/ABL testing strategy yielded results that correlated with the previous qualitative BCR/ABL assay.

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