scholarly journals Urgent care study of the LumiraDx SARS-CoV-2 Ag Test for rapid diagnosis of COVID-19

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Jared Gresh ◽  
Harold Kisner ◽  
Brian DuChateau
Keyword(s):  
False Negative ◽  
False Negative Rate ◽  
Urgent Care ◽  
Reference Laboratory ◽  
Chain Reaction ◽  
Community Based ◽  
Negative Results ◽  
Polymerase Chain ◽  
Care Study ◽  
Regional Reference

Abstract Background Testing individuals suspected of severe acute respiratory syndrome–like coronavirus 2 (SARS-CoV-2) infection is essential to reduce the spread of disease. The purpose of this retrospective study was to determine the false negativity rate of the LumiraDx SARS-CoV-2 Ag Test when utilized for testing individuals suspected of SARS-CoV-2 infection. Methods Concurrent swab samples were collected from patients suspected of SARS-CoV-2 infection by their healthcare provider within two different urgent care centers located in Easton, MA, USA and East Bridgewater, MA, USA. One swab was tested using the LumiraDx SARS-CoV-2 Ag Test. Negative results in patients considered at moderate to high risk of SARS-CoV-2 infection were confirmed at a regional reference laboratory by polymerase chain reaction (PCR) using the additional swab sample. The data included in this study was collected retrospectively as an analysis of routine clinical practice. Results From October 19, 2020 to January 3, 2021, a total of 2241 tests were performed using the LumiraDx SARS-CoV-2 Ag Test, with 549 (24.5%) testing positive and 1692 (75.5%) testing negative. A subset (800) of the samples rendering a negative LumiraDx SARS-CoV-2 Ag Test was also tested using a PCR-based test for SARS-CoV-2. Of this subset, 770 (96.3%) tested negative, and 30 (3.8%) tested positive. Negative results obtained with the LumiraDx SARS-CoV-2 Ag test demonstrated 96.3% agreement with PCR-based tests (CI 95%, 94.7–97.4%). A cycle threshold (CT) was available for 17 of the 30 specimens that yielded discordant results, with an average CT value of 31.2, an SD of 3.0, and a range of 25.2–36.3. CT was > 30.0 in 11/17 specimens (64.7%). Conclusions This study demonstrates that the LumiraDx SARS-CoV-2 Ag Test had a low false-negative rate of 3.8% when used in a community-based setting.

scholarly journals Urgent Care Study of the LumiraDx SARS-CoV-2 Ag Test for Rapid Diagnosis of COVID-19

2021 ◽  
Author(s):  
Jared Gresh ◽  
Harold Kisner ◽  
Brian DuChateau
Keyword(s):  
False Negative ◽  
False Negative Rate ◽  
Rapid Diagnosis ◽  
Urgent Care ◽  
Reference Laboratory ◽  
Swab Sample ◽  
Community Based ◽  
Negative Results ◽  
Care Study ◽  
Regional Reference

Abstract BackgroundTesting individuals suspected of SARS-CoV-2 infection is essential to reduce the spread of disease. The purpose of this study was to determine the false negativity rate of the LumiraDx SARS-CoV-2 Ag Test when utilized for testing individuals suspected of SARS-CoV-2 infection within 12 days of symptom onset. MethodsConcurrent swab samples were collected from patients suspected of SARS-CoV-2 infection by their healthcare provider within two different urgent care centers. One swab was tested using the LumiraDx SARS-CoV-2 Ag Test. Negative results in patients considered at moderate to high risk of SARS-CoV-2 infection were confirmed at a regional reference laboratory by PCR using the additional swab sample. ResultsFrom October 19, 2020 – January 3, 2021, a total of 2241 tests were performed using the LumiraDx SARS-CoV-2 Ag Test, with 549 (24.5%) testing positive and 1692 (75.5%) testing negative. A subset (800) of the samples rendering a negative LumiraDx SARS-CoV-2 Ag Test were also tested using a PCR-based test for SARS-CoV-2. Of this subset, 770 (96.3%) tested negative, and 30 (3.8%) tested positive. A cycle threshold (CT) was available for 17 of the 30 specimens that yielded discordant results, with an average CT value of 31.2, an SD of 3.0, and a range of 25.2–36.3. CT was >30.0 in 11/17 specimens (64.7%). ConclusionsThis study demonstrates that negative results obtained with the LumiraDx SARS-CoV-2 Ag Test had 96.3% agreement with PCR-based SARS-CoV-2 tests, with a low false negative rate of 3.8% when used in a community-based setting.

scholarly journals Urgent Care Study of the LumiraDx SARS-CoV-2 Ag Test for Rapid Diagnosis of COVID-19

2021 ◽  
Author(s):  
Jared Gresh ◽  
Harold Kisner ◽  
Brian DuChateau
Keyword(s):  
False Negative ◽  
False Negative Rate ◽  
Rapid Diagnosis ◽  
Urgent Care ◽  
Reference Laboratory ◽  
Swab Sample ◽  
Community Based ◽  
Negative Results ◽  
Care Study ◽  
Regional Reference

Abstract BackgroundTesting individuals suspected of SARS-CoV-2 infection is essential to reduce the spread of disease. The purpose of this study was to determine the false negativity rate of the LumiraDx SARS-CoV-2 Ag Test when utilized for testing individuals suspected of SARS-CoV-2 infection within 12 days of symptom onset. MethodsConcurrent swab samples were collected from patients suspected of SARS-CoV-2 infection by their healthcare provider within two different urgent care centers. One swab was tested using the LumiraDx SARS-CoV-2 Ag Test. Negative results in patients considered at moderate to high risk of SARS-CoV-2 infection were confirmed at a regional reference laboratory by PCR using the additional swab sample. ResultsFrom October 19, 2020 – January 3, 2021, a total of 2241 tests were performed using the LumiraDx SARS-CoV-2 Ag Test, with 549 (24.5%) testing positive and 1692 (75.5%) testing negative. A subset (800) of the samples rendering a negative LumiraDx SARS-CoV-2 Ag Test were also tested using a PCR-based test for SARS-CoV-2. Of this subset, 770 (96.3%) tested negative, and 30 (3.8%) tested positive. A cycle threshold (CT) was available for 17 of the 30 specimens that yielded discordant results, with an average CT value of 31.2, an SD of 3.0, and a range of 25.2–36.3. CT was >30.0 in 11/17 specimens (64.7%). ConclusionsThis study demonstrates that negative results obtained with the LumiraDx SARS-CoV-2 Ag Test had 96.3% agreement with PCR-based SARS-CoV-2 tests, with a low false negative rate of 3.8% when used in a community-based setting.

scholarly journals UTILITY OF ANTIGEN DETECTION TEST AND POLYMERASE CHAIN REACTION IN THE DIFFERENTIATION OF TUBERCULOUS AND NON-TUBERCULOUS MYCOBACTERIA

2017 ◽  
Vol 10 (6) ◽  
pp. 289
Author(s):  
Yogita Singh ◽  
Raji Vasanth ◽  
Shrikala Baliga ◽  
Dhanashree B
Keyword(s):  
Polymerase Chain Reaction ◽  
False Negative ◽  
Diagnostic Methods ◽  
Clinical Samples ◽  
Chain Reaction ◽  
College Hospital ◽  
Medical College ◽  
Negative Results ◽  
Polymerase Chain ◽  
Mycobacterium Spp

Objectives: Cultivation and identification of mycobacteria to species level remains difficult and time-consuming. Hence, easy and rapid diagnostic methods are necessary for the differentiation of Mycobacterium tuberculosis (MTB) from non-tuberculous mycobacteria (NTM). The present study aims to detect and differentiate MTB from NTM isolated from clinical samples by immunochromatographic test (ICT) and polymerase chain reaction (PCR). Methods: Over a period of 1 year, clinical samples (n=496) received from suspected cases of TB, at the Department of Microbiology, Kasturba Medical College Hospital, Mangalore were cultured to isolate Mycobacterium spp. Identification of all the isolates was done by conventional biochemical technique, ICT, and PCR. Results: Among the 496 samples processed, 49 (9.87%) were acid-fast bacilli smear positive and 59 (11.89%) samples showed the growth of Mycobacterium spp. Among these, 10 were rapid growers, 49 were slow-growing mycobacteria, out of which 30 were MTB as identified by conventional biochemical reaction. Out of 59 Mycobacterial isolates subjected to ICT for the detection of MPT 64 antigen, only 28 were identified as MTB. However, all the 30 isolates were correctly identified as MTB by PCR. Conclusion: Hence, PCR is essential for rapid differentiation of non-tuberculous Mycobacterium from MTB. False negative results seen with immunochromatographic MPT 64 antigen assay could be due to mutations within the mpt64 gene. Further studies are necessary to characterize these PCR-positive and immunochromatographic assay negative MTB isolates.

Polymerase chain reaction detection of melanoma cells in the circulation: relation to clinical stage, surgical treatment, and recurrence from melanoma.

1998 ◽  
Vol 16 (5) ◽  
pp. 1760-1769 ◽  
Author(s):  
B J Curry ◽  
K Myers ◽  
P Hersey
Keyword(s):  
Polymerase Chain Reaction ◽  
Regional Lymph Node ◽  
Clinical Stage ◽  
False Negative ◽  
Primary Melanoma ◽  
Melanoma Cells ◽  
Early Postoperative Period ◽  
Chain Reaction ◽  
Negative Results ◽  
Polymerase Chain

PURPOSE The detection of melanoma cells in the circulation by polymerase chain reaction (PCR) assays has been shown by several investigators to correlate with the stage of the disease and possibly with prognosis. PATIENTS AND METHODS We performed prospective studies on 276 patients with primary melanoma and regional lymph node (LN) metastases to assess the predictive value of PCR detection of tyrosinase and melanoma antigen recognized by T cells-1 (MART-1) in the blood for recurrence of melanoma. RESULTS PCR tests for gp 100, Muc-18, and p97 reacted with RNA in blood from healthy subjects and were considered unsuitable for patient monitoring. The tests were most frequently positive in the first 3 months after surgery. There were 47 recurrences in 123 patients who had been followed up for 18 months. Assays within 3 months of surgery predicted recurrence from melanoma in 66% of the latter (tests for tyrosinase alone detected 51% and MART-1 alone 21% of the patients). Hence, 34% of recurrences were not predicted by tests in the early postoperative period. This did not appear to be because of marker-negative melanoma because summation of tests over the first year identified 89% of those with recurrent disease. CONCLUSION Positive tests were recorded in 35% of patients who remained disease free, but it is too early to assess whether these represent false-positive results. The false-negative results raise the question of whether the assays will provide a reliable basis for selection of patients for adjuvant therapy.

scholarly journals The Use of a Mimic to Detect Polymerase Chain Reaction– Inhibitory Factors in Feces Examined for the Presence of Lawsonia Intracellularis

2003 ◽  
Vol 15 (3) ◽  
pp. 268-273 ◽  
Author(s):  
Magdalena Jacobson ◽  
Stina Englund ◽  
András Ballagi-Pordány
Keyword(s):  
Polymerase Chain Reaction ◽  
False Negative ◽  
Clinical Samples ◽  
Lawsonia Intracellularis ◽  
Chain Reaction ◽  
Fecal Samples ◽  
Wild Boars ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain

Lawsonia intracellularis is an intracellular organism that causes proliferative enteritis in pigs. This bacterium is difficult to culture, and antemortem demonstration of the microbe is therefore often performed on fecal samples by polymerase chain reaction (PCR). Polymerase chain reaction is sensitive and specific, but inhibitory factors in feces might cause false-negative results. This article describes the construction and use of an internal standard, a mimic. The mimic is amplified by the same primers as those used for L. intracellularis DNA and thus could indicate false-negative results in clinical samples. The amplicon was clearly visible when as few as 10 mimic molecules were added per amplification reaction and when no inhibitors were present. When fecal samples were spiked with the mimic, the detection limit was 102 molecules per PCR. Sixty clinical samples, 20 from wild boars, 20 from growing pigs with diarrhea, and 20 from pigs without diarrhea, were prepared by a boiling procedure and subjected to PCR together with 103 mimic molecules. Nine samples were positive, of which 7 originated from pigs with diarrhea and 2 from pigs without diarrhea. In 14 samples from wild boars, in 8 samples from pigs without diarrhea, and in 3 samples from pigs with diarrhea, neither the mimic nor the target DNA was visible. This indicated the presence of inhibitors in these samples. It is concluded that the mimic can be used as an internal control in the diagnosis of L. intracellularis to indicate inhibition of PCR.

scholarly journals COVID-19 automatic diagnosis with CT images using the novel Transformer architecture

2021 ◽  
Author(s):  
Gabriel Sousa Silva Costa ◽  
Anselmo C. Paiva ◽  
Geraldo Braz Júnior ◽  
Marco Melo Ferreira
Keyword(s):  
Intelligent System ◽  
State Of The Art ◽  
False Negative ◽  
False Negative Rate ◽  
Ct Images ◽  
The Novel ◽  
Chain Reaction ◽  
High False Negative Rate ◽  
Polymerase Chain ◽  
Low Sensitivity

Even though vaccines are already in use worldwide, the COVID-19 pandemic is far from over, with some countries re-establishing the lockdown state, the virus has taken over 2 million lives until today, being a serious health issue. Although real-time reverse transcription-polymerase chain reaction (RTPCR) is the first tool for COVID-19 diagnosis, its high false-negative rate and low sensitivity might delay accurate diagnosis. Therefore, fast COVID-19 diagnosis and quarantine, combined with effective vaccination plans, is crucial for the pandemic to be over as soon as possible. To that end, we propose an intelligent system to classify computed tomography (CT) of lung images between a normal, pneumonia caused by something other than the coronavirus or pneumonia caused by the coronavirus. This paper aims to evaluate a complete selfattention mechanism with a Transformer network to capture COVID-19 pattern over CT images. This approach has reached the state-of-the-art in multiple NLP problems and just recently is being applied for computer vision tasks. We combine vision transformer and performer (linear attention transformers), and also a modified vision transformer, reaching 96.00% accuracy.

scholarly journals Reducing False Negative PCR Test for COVID-19

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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