Variplex™ test system fails to reliably detect SARS-CoV-2 directly from respiratory samples without RNA extraction

AbstractDiagnosis of COVID is performed by PCR methods, but their capacity is limited by the requirement of high-level facilities and instruments. The loop-mediated isothermal amplification (LAMP) method has been utilized for the detection of isolated virus-specific RNA. Preliminary data suggest the possibility of isothermal amplification directly from respiratory samples without RNA extraction. All patients admitted to our hospital were screened for SARS-CoV-2 by routine. Respiratory samples were tested by variplex system based on LAMP method directly without RNA extraction and by PCR. Primary endpoint was the false-negative rate of variplex test compared with PCR as gold standard. In 109 patients variplex test and PCR assay were performed simultaneously. Median age was 80 years and male/female ratio was 40/60%. The prevalence of PCR-confirmed COVID diagnosis was 43.1%. Variplex test was positive in 13.8%. False-negative rate of variplex test compared with PCR was 83.0%. The potential of LAMP technology using isolated RNA has been demonstrated impressively by others, and excellent sensitivity and specificity of detecting SARS-CoV-2 has been reported. However, without RNA extraction, the variplex test system failed to reliably detect SARS-CoV-2 directly in respiratory samples.

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VariplexTM test system fails to reliably detect SARS-CoV-2 directly from respiratory samples without RNA extraction

10.21203/rs.3.rs-33871/v1 ◽

2020 ◽

Author(s):

Florian Eckel ◽

Franziska Küsters ◽

Bernhard Drossel ◽

Markus Konert ◽

Hans Mattes ◽

...

Keyword(s):

False Negative ◽

Rna Extraction ◽

False Negative Rate ◽

Test System ◽

Isothermal Amplification ◽

Lamp Method ◽

Pcr Assay ◽

Female Ratio ◽

Negative Rate ◽

High Level

Abstract Diagnosis of COVID is performed by PCR methods, but their capacitiy is limited by the requirement of high-level facilities and instruments. The loop-mediated isothermal amplification (LAMP) method has been utilized for the detection of isolated virus-specific RNA. Preliminary data suggest the possibility of isothermal amplification directly from respiratory samples without RNA extraction.All patients admitted to our hospital were screened for SARS-CoV-2 by routine. Respiratory samples were tested by variplex system based on LAMP method directly without RNA extraction and by PCR. Confirmation or exclusion of clinical COVID diagnosis was based on history, examination and findings. Primary endpoint was the false negative rate of variplex test compared to PCR.A total of 153 patients were included in the study. Median age was 79 years and male/female ratio was 45%/55%. Prevalence of clinical COVID diagnosis was 61.4%. Variplex test and PCR assay was positive in 15.0% and 45.5%, respectively. In 109 patients variplex test and PCR assay were performed simultaneously. False negative rate of variplex test compared to PCR was 83.0%.The potential of LAMP-technology using isolated RNA has been demonstrated impressively by others and excellent sensitivity and specivity of detecting SARS-CoV-2 has been reported. However, without RNA extraction the variplex test system failed to reliable detect SARS-CoV-2 directly in respiratory samples.

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Does the false‐negative rate for 1 or 2 negative sentinel nodes after neo‐adjuvant chemotherapy translate into a high local recurrence rate?

The Breast Journal ◽

10.1111/tbj.14206 ◽

2021 ◽

Author(s):

Nicole E. Sharp ◽

Darren B. Sachs ◽

Nicole M. Melchior ◽

Philip Albaneze ◽

Salvatore Nardello ◽

...

Keyword(s):

Adjuvant Chemotherapy ◽

Local Recurrence ◽

Recurrence Rate ◽

Local Recurrence Rate ◽

False Negative ◽

False Negative Rate ◽

Sentinel Nodes ◽

Negative Rate ◽

High Local Recurrence Rate ◽

Neo Adjuvant Chemotherapy

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Effects of Previous Surgery on the Detection of Sentinel Nodes in Women With Vulvar Cancer

International Journal of Gynecological Cancer ◽

10.1097/igc.0b013e31822dbe3c ◽

2011 ◽

Vol 21 (9) ◽

pp. 1679-1683 ◽

Cited By ~ 10

Author(s):

Tessa A. Ennik ◽

David G. Allen ◽

Ruud L.M. Bekkers ◽

Simon E. Hyde ◽

Peter T. Grant

Keyword(s):

Vulvar Cancer ◽

False Negative ◽

False Negative Rate ◽

Blue Dye ◽

Previous Surgery ◽

Detection Rates ◽

Reliable Technique ◽

Appearance Time ◽

Negative Rate ◽

Significant Difference

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.

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Temporal dynamics of viral load and false negative rate influence the levels of testing necessary to combat COVID-19 spread

Scientific Reports ◽

10.1038/s41598-021-88498-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Katherine F. Jarvis ◽

Joshua B. Kelley

Keyword(s):

Viral Load ◽

Temporal Dynamics ◽

Reproduction Number ◽

False Negative ◽

False Negative Rate ◽

Agent Based Model ◽

Agent Based ◽

Viral Spread ◽

Negative Rate

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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High mortality with High false negative rate: COVID-19 infection in patients with hematologic malignancies

Leukemia Research ◽

10.1016/j.leukres.2021.106582 ◽

2021 ◽

Vol 106 ◽

pp. 106582

Author(s):

Alex Niu ◽

Bo Ning ◽

Francisco Socola ◽

Hana Safah ◽

Tim Reynolds ◽

...

Keyword(s):

High Mortality ◽

False Negative ◽

False Negative Rate ◽

Hematologic Malignancies ◽

Negative Rate ◽

High False Negative Rate

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489 The Role of Sentinel Lymph Node Biopsy in Cutaneous Head and Neck Melanoma: A Systematic Review and Meta-Analysis

British Journal of Surgery ◽

10.1093/bjs/znab134.289 ◽

2021 ◽

Vol 108 (Supplement_2) ◽

Author(s):

E Johnston ◽

S Taylor ◽

F Bannon ◽

S McAllister

Keyword(s):

Lymph Node ◽

Sentinel Lymph Node ◽

Sentinel Lymph Node Biopsy ◽

Head And Neck ◽

False Negative ◽

False Negative Rate ◽

Lymph Node Biopsy ◽

Node Biopsy ◽

Negative Rate ◽

Sentinel Node Identification

Abstract Introduction and Aims The aim of this systematic review is to provide an up-to-date evaluation of the role and test performance of sentinel lymph node biopsy (SLNB) in the head and neck. Method This review follows the PRISMA guidelines. Database searches for MEDLINE and EMBASE were constructed to retrieve human studies published between 1st January 2010 and 1st July 2020 assessing the role and accuracy of sentinel lymph node biopsy in cutaneous malignant melanoma of the head and neck. Articles were independently screened by two reviewers and critically appraised using the MINORS criteria. The primary outcomes consisted of the sentinel node identification rate and test-performance measures, including the false-negative rate and the posttest probability negative. Results A total of 27 studies, including 4688 patients, met the eligibility criteria. Statistical analysis produced weighted summary estimates for the sentinel node identification rate of 97.3% (95% CI, 95.9% to 98.6%), the false-negative rate of 21.3% (95% CI, 17.0% to 25.4%) and the posttest probability negative of 4.8% (95% CI, 3.9% to 5.8%). Discussion Sentinel lymph node biopsy is accurate and feasible in the head and neck. Despite technical improvements in localisation techniques, the false negative rate remains disproportionately higher than for melanoma in other anatomical sites.

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Assessment of Lymph Node Involvement with PET-CT in Advanced Epithelial Ovarian Cancer. A FRANCOGYN Group Study

Journal of Clinical Medicine ◽

10.3390/jcm10040602 ◽

2021 ◽

Vol 10 (4) ◽

pp. 602

Author(s):

Antoine Tardieu ◽

Lobna Ouldamer ◽

François Margueritte ◽

Lauranne Rossard ◽

Aymeline Lacorre ◽

...

Keyword(s):

Lymph Node ◽

False Negative ◽

False Negative Rate ◽

Lymph Node Involvement ◽

Accuracy Rate ◽

Peritoneal Cancer ◽

Negative Rate ◽

Number Of Patients ◽

Pet Ct ◽

Node Involvement

The objective of our study is to evaluate the diagnostic performance of positron emission tomography/computed tomography (PET-CT) for the assessment of lymph node involvement in advanced epithelial ovarian, fallopian tubal or peritoneal cancer (EOC). This was a retrospective, bicentric study. We included all patients over 18 years of age with a histological diagnosis of advanced EOC who had undergone PET-CT at the time of diagnosis or prior to cytoreduction surgery with pelvic or para-aortic lymphadenectomy. We included 145 patients with primary advanced EOC. The performance of PET-CT was calculated from the data of 63 patients. The sensitivity of PET-CT for preoperative lymph node evaluation was 26.7%, specificity was 90.9%, PPV was 72.7%, and NPV was 57.7%. The accuracy rate was 60.3%, and the false-negative rate was 34.9%. In the case of primary cytoreduction (n = 16), the sensitivity of PET-CT was 50%, specificity was 87.5%, PPV was 80%, and NPV was 63.6%. The accuracy rate was 68.8%, and the false negative rate was 25%. After neoadjuvant chemotherapy (n = 47), the sensitivity of PET-CT was 18.2%, specificity was 92%, PPV was 66.7%, and NPV was 56.1%. The accuracy rate was 57.5%, and the false negative rate was 38.3%. Due to its high specificity, the performance of a preoperative PET-CT scan could contribute to the de-escalation and reduction of lymphadenectomy in the surgical management of advanced EOC in a significant number of patients free of lymph node metastases.

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Diagnostic Accuracy of Magnetic Resonance Imaging and Computed Tomography Scan in Young Athletes With Spondylolysis

Clinical Pediatrics ◽

10.1177/0009922819832643 ◽

2019 ◽

Vol 58 (6) ◽

pp. 671-676

Author(s):

Amy M. West ◽

Pierre A. d’Hemecourt ◽

Olivia J. Bono ◽

Lyle J. Micheli ◽

Dai Sugimoto

Keyword(s):

Magnetic Resonance Imaging ◽

Computed Tomography ◽

Magnetic Resonance ◽

Ct Scan ◽

False Negative ◽

False Negative Rate ◽

Ct Scans ◽

Resonance Imaging ◽

Young Athletes ◽

Negative Rate

The objective of this study was to determine diagnostic accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) scans in young athletes diagnosed with spondylolysis. A cross-sectional study was used. Twenty-two young athletes (14.7 ± 1.5 years) were diagnosed as spondylolysis based on a single-photon emission CT. Following the diagnosis, participants underwent MRI and CT scan imaging tests on the same day. The sensitivity and false-negative rate of the MRI and CT scans were analyzed. MRI test confirmed 13 (+) and 9 (−) results while CT test showed 17 (+) and 5 (−) results. The sensitivity and false-negative rate of MRI were, respectively, 59.1% (95% confidence interval [CI] = 36.7% to 78.5%) and 40.9% (95% CI = 21.5% to 63.3%). Furthermore, the sensitivity and false-negative rate of CT scan were 77.3% (95% CI = 54.2% to 91.3%) and 22.7% (95% CI = 0.09% to 45.8%). Our results indicated that CT scan is a more accurate imaging modality to diagnose spondylolysis compared with MRI in young athletes.

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