scholarly journals Does CT help in reducing RT-PCR false negative rate for COVID-19?

2021 ◽  
Vol 31 (5) ◽  
pp. 80
Author(s):  
RichaD Jain ◽  
Anirudh Kohli ◽  
Anagha Joshi ◽  
Ankur Shah ◽  
Abhishek Gorlawar ◽  
...  
Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1425
Author(s):  
Xin Xie ◽  
Tamara Gjorgjieva ◽  
Zaynoun Attieh ◽  
Mame Massar Dieng ◽  
Marc Arnoux ◽  
...  

A major challenge in controlling the COVID-19 pandemic is the high false-negative rate of the commonly used RT-PCR methods for SARS-CoV-2 detection in clinical samples. Accurate detection is particularly challenging in samples with low viral loads that are below the limit of detection (LoD) of standard one- or two-step RT-PCR methods. In this study, we implemented a three-step approach for SARS-CoV-2 detection and quantification that employs reverse transcription, targeted cDNA preamplification, and nano-scale qPCR based on a commercially available microfluidic chip. Using SARS-CoV-2 synthetic RNA and plasmid controls, we demonstrate that the addition of a preamplification step enhances the LoD of this microfluidic RT-qPCR by 1000-fold, enabling detection below 1 copy/µL. We applied this method to analyze 182 clinical NP swab samples previously diagnosed using a standard RT-qPCR protocol (91 positive, 91 negative) and demonstrate reproducible and quantitative detection of SARS-CoV-2 over five orders of magnitude (<1 to 106 viral copies/µL). Crucially, we detect SARS-CoV-2 with relatively low viral load estimates (<1 to 40 viral copies/µL) in 17 samples with negative clinical diagnosis, indicating a potential false-negative rate of 18.7% by clinical diagnostic procedures. In summary, this three-step nano-scale RT-qPCR method can robustly detect SARS-CoV-2 in samples with relatively low viral loads (<1 viral copy/µL) and has the potential to reduce the false-negative rate of standard RT-PCR-based diagnostic tests for SARS-CoV-2 and other viral infections.


2011 ◽  
Vol 29 (32) ◽  
pp. 4279-4285 ◽  
Author(s):  
David J. Dabbs ◽  
Molly E. Klein ◽  
Syed K. Mohsin ◽  
Raymond R. Tubbs ◽  
Yongli Shuai ◽  
...  

Purpose HER2 (ERBB2) status is an important prognostic and predictive marker in breast carcinoma. In recent years, Genomic Health (GHI), purveyors of the Oncotype DX test, has been separately reporting HER2 by reverse transcription polymerase chain reaction (RT-PCR) to oncologists. Because of the lack of independent evaluation, this quality assurance study was undertaken to define the concordance rate between immunohistochemistry (IHC)/fluorescent in situ hybridization (FISH) and GHI RT-PCR HER2 assay. Methods All patients at three participating laboratories (Magee-Womens Hospital [Pittsburgh, PA], Cleveland Clinic [Cleveland, OH], and Riverside Methodist Hospital [Columbus, OH]) with available HER2 RT-PCR results from GHI were included in this study. All IHC-positive and equivocal patient cases were further evaluated and classified by FISH at respective laboratories. Results Of the total 843 patient cases, 784 (93%) were classified as negative, 36 (4%) as positive, and 23 (3%) as equivocal at the three institutions using IHC/FISH. Of the 784 negative patient cases, 779 (99%) were also classified as negative by GHI RT-PCR assay. However, all 23 equivocal patient cases were reported as negative by GHI. Of the 36 positive cases, only 10 (28%; 95% CI, 14% to 45%) were reported as positive, 12 (33%) as equivocal, and 14 (39%) as negative. Conclusion There was an unacceptable false-negative rate for HER2 status with GHI HER2 assay in this independent study. This could create confusion in the decision-making process for targeted treatment and potentially lead to mismanagement of patients with breast cancer if only GHI HER2 information is used.


Author(s):  
Ramy Arnaout ◽  
Rose A. Lee ◽  
Ghee Rye Lee ◽  
Cody Callahan ◽  
Christina F. Yen ◽  
...  

AbstractResolving the COVID-19 pandemic requires diagnostic testing to determine which individuals are infected and which are not. The current gold standard is to perform RT-PCR on nasopharyngeal samples. Best-in-class assays demonstrate a limit of detection (LoD) of ~100 copies of viral RNA per milliliter of transport media. However, LoDs of currently approved assays vary over 10,000-fold. Assays with higher LoDs will miss more infected patients, resulting in more false negatives. However, the false-negative rate for a given LoD remains unknown. Here we address this question using over 27,500 test results for patients from across our healthcare network tested using the Abbott RealTime SARS-CoV-2 EUA. These results suggest that each 10-fold increase in LoD is expected to increase the false negative rate by 13%, missing an additional one in eight infected patients. The highest LoDs on the market will miss a majority of infected patients, with false negative rates as high as 70%. These results suggest that choice of assay has meaningful clinical and epidemiological consequences. The limit of detection matters.


Author(s):  
Lauren M Kucirka ◽  
Stephen A Lauer ◽  
Oliver Laeyendecker ◽  
Denali Boon ◽  
Justin Lessler

ABSTRACTSARS-CoV-2 RT-PCR based tests are being used to “rule out” infection among high-risk individuals such as exposed inpatients and healthcare workers. It is critical to understand how the predictive value of the test varies with time from exposure and symptom onset in order to avoid being falsely reassured by negative tests. As such, the goal of our study was to estimate the false negative rate by day since infection. We used previously published data on RT-PCR sensitivity on samples derived from nasal swabs by day since symptom onset (n=633) and fit a cubic polynomial spline to calculate the false negative rate by day since exposure and symptom onset. Over the four days of infection prior to the typical time of symptom onset (day 5) the probability of a false negative test in an infected individual falls from 100% on day one (95% CI 69-100%) to 61% on day four (95% CI 18-98%), though there is considerable uncertainty in these numbers. On the day of symptom onset, the median false negative rate was 39% (95% CI 16-77%). This decreased to 26% (95% CI 18-34%) on day 8 (3 days after symptom onset), then began to rise again, from 27% (95% CI 20-34%) on day 9 to 61% (95% CI 54-67%) on day 21. Care must be taken when interpreting RT-PCR tests for SARS-CoV-2 infection, particularly if performed early in the course of infection, when using these results as a basis for removing precautions intended to prevent onward transmission. If there is high clinical suspicion, patients should not be ruled out on the basis of RT-PCR alone, and the clinical and epidemiologic situation should be carefully considered.


2020 ◽  
Author(s):  
Xin Xie ◽  
Tamara Gjorgjieva ◽  
Zaynoun Attieh ◽  
Mame Massar Dieng ◽  
Marc Arnoux ◽  
...  

Background: A major challenge in controlling the COVID-19 pandemic is the high false-negative rate of the commonly used standard RT-PCR methods for SARS-CoV-2 detection in clinical samples. Accurate detection is particularly challenging in samples with low viral loads that are below the limit of detection (LoD) of standard one- or two-step RT-PCR methods. Methods: We implement a three-step approach for SARS-CoV-2 detection and quantification that employs reverse transcription, targeted cDNA preamplification and nano-scale qPCR based on the Fluidigm 192.24 microfluidic chip. We validate the method using both positive controls and nasopharyngeal swab samples. Results: Using SARS-CoV-2 synthetic RNA and plasmid controls, we demonstrate that the addition of a preamplification step enhances the LoD of the Fluidigm method by 1,000-fold, enabling detection below 1 copy/μl. We applied this method to analyze 182 clinical NP swab samples previously diagnosed using a standard RT-qPCR protocol (91 positive, 91 negative) and demonstrate reproducible detection of SARS-CoV-2 over five orders of magnitude (< 1 to 106 viral copies/μl). Crucially, we detect SARS-CoV-2 with relatively low viral load estimates (<1 to 40 viral copies/μl) in 17 samples with negative clinical diagnosis, indicating a potential false negative rate of 18.7% by clinical diagnostic procedures. Conclusion: The three-step nano-scale RT-qPCR method can robustly detect SARS-CoV-2 in samples with relatively low viral loads (< 1 viral copy/μl) and has the potential to reduce the false negative rate of standard RT-PCR-based diagnostic tests for SARS-CoV-2 and other viral infections.


Author(s):  
Linjiajie Fang ◽  
Bing-Yi Jing ◽  
Shen Ling ◽  
Qing Yang

AbstractAs the COVID-19 pandemic continues worldwide, there is an urgent need to detect infected patients as quickly and accurately as possible. Group testing proposed by Technion [1][2] could improve efficiency greatly. However, the false negative rate (FNR) would be doubled. Using USA as an example, group testing would have over 70,000 false negatives, compared to 35,000 false negatives by individual testing.In this paper, we propose a Flexible, Accurate and Speedy Test (FAST), which is faster and more accurate than any existing tests. FAST first forms small close contact subgroups, e.g. families and friends. It then pools subgroups to form larger groups before RT-PCR test is done. FAST needs a similar number of tests to Technion’s method, but sharply reduces the FNR to a negligible level. For example, FAST brings down the number of false negatives in USA to just 2000, and it is seven times faster than individual testing.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 6-7
Author(s):  
Alex Niu ◽  
Bo Ning ◽  
Francisco Socola ◽  
Hana Safah ◽  
Tim Reynolds ◽  
...  

Introduction Patients with hematological malignancies (HM) are uniquely immunocompromised and considered at high risk for COVID-19. However, data regarding the diagnosis, clinical course, treatment, and outcomes of these patients is sparse. In particular, the ability to successfully detect SARS-CoV-2 in patients with HM remains unknown. We have previously reported 2 cases of allogeneic stem cell transplant (SCT) diagnosed with COVID-19 using clustered regularly interspaced short palindromic repeats (CRISPR) technique, following multiple negative nasopharyngeal RT-PCR testing (Niu et al. Bone Marrow Transplantation - Nature). Here we examine 29 patients with a variety of HM with high suspicion for COVID-19 based on clinical presentation, lab results, and imaging, whom were tested with CRISPR and/or RT-PCR based techniques. From 3/31/20 to 7/17/20, 29 patients (age 24 to 82) with a variety of HM (20 lymphoid, 9 myeloid; Table 1), 24 of which presented with an undiagnosed respiratory illness and 5 presented while asymptomatic for testing prior to chemotherapy, were evaluated for COVID-19. While 16 patients tested positive for COVID-19 with guideline-directed nasopharyngeal RT-PCR testing (including the 5 asymptomatic patients), 13 patients tested negative with the same technique. However, based on their clinical history, imaging, and disease course, concern for COVID-19 infection remained in these 13 patients. We then used CRISPR technology available at our institution (Huang et al. Biosensors and Bioelectronics) to test 8 patients who initially tested negative by RT-PCR. Surprisingly, 7 of the 8 patients tested positive for COVID-19 with either a blood sample and/or nasal swab for the SARS-CoV-2 specific N gene and ORF1ab gene. Excluding the patients who were negative by RT-PCR and not tested by CRISPR, the rate of false negativity with RT-PCR testing is significantly elevated at 29% (7/24) in our cohort of HM, which compares unfavorably with the expected false negative rates of RT-PCR techniques. A very high fatality rate was observed with 9 out of the 29 patients (31%) ultimately dying. Fifteen patients were undergoing active chemotherapy, 4 had received an autologous SCT, 6 had received an allogeneic SCT, and 4 were on surveillance. Of the 23 COVID-19 positive patients (by RT-PCR or CRISPR), 8 patients received COVID-19-directed therapy with either hydroxychloroquine/azithromycin, remdesivir, and/or Covid-19 convalescent plasma (CCP) depending on their clinical status, and 4 patients expired. Of the 8 treated patients, 7 improved while 1 patient expired. For the 5 patients who were negative for RT-PCR with no CRISPR completed, 1 patient received hydroxychloroquine/azithromycin proactively due to symptoms and imaging and recovered, while 3 patients expired at outside facilities due to unknown causes. Breakdown of testing and treatment is shown in Fig. 1. The majority of our patients had undergone SCT or were actively on chemotherapy, notably lymphodepleting chemotherapy. Associated with the fact that COVID-19 is known to worsen lymphopenia, our patient's symptoms and immune response to COVID-19 is likely to differ from immunocompetent hosts. This translated into an overall worse outcome as seen by the high mortality with our patients. In our limited dataset, patients presented with a variety of symptoms ranging from asymptomatic to acute respiratory failure. Intriguingly, the 5 asymptomatic patients had lymphoid malignancies and were on chemotherapy. It is thus imperative to establish the diagnosis of COVID-19 quickly, as faster initiation of treatment has been associated with better outcomes. The 8 patients who were diagnosed and treated improved substantially. However, as seen by our dataset, a strikingly high false negative rate was observed. Thus, a high clinical suspicion must guide further workup and therapy in patients with HM who present with an undiagnosed respiratory illness consistent with COVID-19. Patients with HM can have a wide variety of presentations when infected with COVID-19. For this select patient population we must establish an algorithm to diagnose COVID-19 efficiently as we reported a high number of initial false negative COVID-19 tests before the more sensitive CRISPR revealed a positive test. In addition, treatment pathways need to be instituted to not only treat COVID-19 infection, but also provide the best treatment for these patient's underlying HM. Disclosures Safah: Amgen: Honoraria; Verastem: Honoraria; Janssen: Speakers Bureau; Astellas: Speakers Bureau. Saba:Kite: Other: Advisory Board; Pharmacyclics: Other: Advisory Board, Speakers Bureau; AbbVie: Consultancy, Other: Advisory Board, Speakers Bureau; Janssen: Other: Advisory Board, Speakers Bureau; Kyowa Kirin: Other: Advisory Board.


2011 ◽  
Vol 21 (9) ◽  
pp. 1679-1683 ◽  
Author(s):  
Tessa A. Ennik ◽  
David G. Allen ◽  
Ruud L.M. Bekkers ◽  
Simon E. Hyde ◽  
Peter T. Grant

BackgroundThere is a growing interest to apply the sentinel node (SN) procedure in the treatment of vulvar cancer. Previous vulvar surgery might disrupt lymphatic patterns and thereby decrease SN detection rates, lengthen scintigraphic appearance time (SAT), and increase SN false-negative rate. The aims of this study were to evaluate the SN detection rates at the Mercy Hospital for Women in Melbourne and to investigate whether previous vulvar surgery affects SN detection rates, SAT, and SN false-negative rate.MethodsData on all patients with vulvar cancer who underwent an SN procedure (blue dye, technetium, or combined technique) from November 2000 to July 2010 were retrospectively collected.ResultsSixty-five SN procedures were performed. Overall detection rate was 94% per person and 80% per groin. Detection rates in the group of patients who underwent previous excision of the primary tumor were not lower compared with the group without previous surgery or with just an incisional biopsy. There was no statistical significant difference in SAT between the previous excision group and the other patients. None of the patients with a false-negative SN had undergone previous excision.ConclusionsResults indicate that previous excision of a primary vulvar malignancy does not decrease SN detection rates or increase SN false-negative rate. Therefore, the SN procedure appears to be a reliable technique in patients who have previously undergone vulvar surgery. Previous excision did not significantly lengthen SAT, but the sample size in this subgroup analysis was small.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Katherine F. Jarvis ◽  
Joshua B. Kelley

AbstractColleges and other organizations are considering testing plans to return to operation as the COVID-19 pandemic continues. Pre-symptomatic spread and high false negative rates for testing may make it difficult to stop viral spread. Here, we develop a stochastic agent-based model of COVID-19 in a university sized population, considering the dynamics of both viral load and false negative rate of tests on the ability of testing to combat viral spread. Reported dynamics of SARS-CoV-2 can lead to an apparent false negative rate from ~ 17 to ~ 48%. Nonuniform distributions of viral load and false negative rate lead to higher requirements for frequency and fraction of population tested in order to bring the apparent Reproduction number (Rt) below 1. Thus, it is important to consider non-uniform dynamics of viral spread and false negative rate in order to model effective testing plans.


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