scholarly journals The value of repeat patient testing for SARS-CoV-2: real-world experience during the first wave

2021 ◽  
Vol 3 (7) ◽  
Author(s):  
Alex Zhu ◽  
Margaret Creagh ◽  
Chao Qi ◽  
Shannon Galvin ◽  
Maureen Bolon ◽  
...  
Keyword(s):  
False Negative ◽  
Laboratory Diagnosis ◽  
Nucleic Acid Amplification ◽  
Repeat Testing ◽  
The Third ◽  
Reverse Transcription Pcr ◽  
Negative Results ◽  
False Negative Results ◽  
Number Of Patients ◽  
Control And Prevention

Introduction. Reports of false-negative quantitative reverse transcription PCR (RT-qPCR) results from patients with high clinical suspension for coronavirus disease 2019 (COVID-19), suggested that a negative result produced by a nucleic acid amplification assays (NAAs) did not always exclude the possibility of COVID-19 infection. Repeat testing has been used by clinicians as a strategy in an to attempt to improve laboratory diagnosis of COVID-19 and overcome false-negative results in particular. Aim. To investigate whether repeat testing is helpful for overcoming false-negative results. Methods. We retrospectively reviewed our experience with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing, focusing on the yield of repeat patient testing for improving SARS-CoV-2 detection by NAA. Results. We found that the yield from using repeat testing to identify false-negative patients was low. When the first test produced a negative result, only 6 % of patients tested positive by the second test. The yield decreased to 1.7 and then 0 % after the third and fourth tests, respectively. When comparing the results produced by three assays, the Centers for Disease Control and Prevention (CDC) SARS CoV-2 RT-qPCR panel, Xpert Xpress CoV-2 and ID NOW COVID-19, the ID NOW assay was associated with the highest number of patients who tested negative initially but positive on repeat testing. The CDC SARS CoV-2 RT-qPCR panel produced the highest number of indeterminate results. Repeat testing resolved more than 90 % of indeterminate/invalid results. Conclusions. The yield from using repeat testing to identify false-negative patients was low. Repeat testing was best used for resolving indeterminate/invalid results.

scholarly journals Five days of fever and myocardial inflammation

2021 ◽  
Vol 9 ◽  
pp. 2050313X2110508
Author(s):  
Keli D Coleman ◽  
Paul Benz ◽  
Nirzar S Parikh ◽  
Danny G Thomas ◽  
David Segar ◽  
...  
Keyword(s):  
False Negative ◽  
Clinical Signs ◽  
Myocardial Inflammation ◽  
Negative Results ◽  
Pediatric Illness ◽  
Multisystem Involvement ◽  
False Negative Results ◽  
Control And Prevention ◽  
Evidence Based Guidelines ◽  
Inflammatory Syndrome

Multisystem inflammatory syndrome in children is an emerging pediatric illness associated with severe acute respiratory syndrome coronavirus 2 infection. The syndrome is rare, and evidence-based guidelines are lacking. This report reviews a patient who presented for medical care multiple times early in the course of his illness, thus offering near-daily documentation of symptoms and laboratory abnormalities. The patient did not have thrombocytopenia, anemia, or myocardial inflammation until the fifth day of fever. These laboratory abnormalities coincided with the onset of rash, conjunctival injection, vomiting, and diarrhea: clinical signs that could serve as indicators for when to obtain blood tests. The timing of this patient’s onset of multisystem involvement suggests that testing for multisystem inflammatory syndrome in children after only 24 h of fever, as the Centers for Disease Control and Prevention recommends, may yield false-negative results. Testing for multisystem inflammatory syndrome in children after 4 days of fever may be more reliable.

scholarly journals Enhancement of the AMPLICOR Enterovirus PCR Test with a Coprecipitant

1998 ◽  
Vol 36 (11) ◽  
pp. 3408-3409 ◽  
Author(s):  
E. William Taggart ◽  
Carrie L. Byington ◽  
David R. Hillyard ◽  
John E. Robison ◽  
Karen C. Carroll
Keyword(s):  
Test Specimen ◽  
False Negative ◽  
Blind Study ◽  
Specimen Preparation ◽  
Background Signal ◽  
Repeat Testing ◽  
Negative Results ◽  
Data Support ◽  
False Negative Results ◽  
Pcr Test

The incorporation of a commercially available coprecipitant into the AMPLICOR enterovirus PCR test specimen preparation enhanced the sensitivity and reproducibility of this assay. Fifty-five previously tested archived cerebrospinal fluids (CSF) specimens were tested in a blind study in duplicate with and without Pellet Paint coprecipitant (Novagen, Inc., Madison, Wis.). Of these specimens, 26 had previously been determined to be positive and 29 had previously been determined to be negative. All previously positive CSF specimens were positive when Pellet Paint was used and only 18 were positive without Pellet Paint. No previously negative specimens were positive on repeat testing with or without Pellet Paint. The background signal was not affected by the addition of Pellet Paint. These data support the utility of a coprecipitant in minimizing false-negative results.

scholarly journals Limitations of a Commercial Assay as Diagnostic Test of Autoimmune Encephalitis

2021 ◽  
Vol 12 ◽  
Author(s):  
Raquel Ruiz-García ◽  
Guillermo Muñoz-Sánchez ◽  
Laura Naranjo ◽  
Mar Guasp ◽  
Lidia Sabater ◽  
...  
Keyword(s):  
False Negative ◽  
Autoimmune Encephalitis ◽  
Clinical Syndrome ◽  
The Other ◽  
Transfected Cells ◽  
Negative Results ◽  
Clinical Laboratories ◽  
False Negative Results ◽  
Number Of Patients ◽  
Separate Cohort

Detection of neuronal surface antibodies (NSAb) is important for the diagnosis of autoimmune encephalitis (AE). Although most clinical laboratories use a commercial diagnostic kit (Euroimmun, Lübeck, Germany) based on indirect immunofluorescence on transfected cells (IIFA), clinical experience suggests diagnostic limitations. Here, we assessed the performance of the commercial IIFA in serum and CSF samples of patients with suspected AE previously examined by rat brain immunohistochemistry (Cohort A). Of 6213 samples, 404 (6.5%) showed brain immunostaining suggestive of NSAb: 163 (40%) were positive by commercial IIFA and 241 (60%) were negative. When these 241 samples were re-assessed with in-house IIFA, 42 (18%) were positive: 21 (9%) had NSAb against antigens not included in the commercial IIFA and the other 21 (9%) had NSAb against antigens included in the commercial kit (false negative results). False negative results occurred more frequently with CSF (29% vs 10% in serum) and predominantly affected GABABR (39%), LGI1 (17%) and AMPAR (11%) antibodies. Results were reproduced in a separate cohort (B) of 54 AE patients with LGI1, GABABR or AMPAR antibodies in CSF which were missed in 30% by commercial IIFA. Patients with discordant GABABR antibody results (positive in-house but negative commercial IIFA) were less likely to develop full-blown clinical syndrome; no significant clinical differences were noted for the other antibodies. Overall, NSAb testing by commercial IIFA led to false negative results in a substantial number of patients, mainly those affected by anti-LG1, GABABR or AMPAR encephalitis. If these disorders are suspected and commercial IIFA is negative, more comprehensive antibody studies are recommended.

Problematic aspects of diagnostics of mers-CoV-2 coronavirus infection using reverse-transcriptional PCR

Biomics ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 564-590
Author(s):  
A.R. Mavzyutov ◽  
R.R. Garafutdinov ◽  
E.Yu. Khalikova ◽  
R.A. Yuldashev ◽  
R.I. Khusainova ◽  
...  
Keyword(s):  
False Negative ◽  
Virus Genome ◽  
Test System ◽  
Probability Of Detection ◽  
Nucleic Acid Amplification ◽  
Negative Results ◽  
Hybridization Probes ◽  
False Negative Results ◽  
Coronavirus Infection ◽  
The One

The paper considers the problematic aspects of detecting a new coronavirus infection using RT-PCR, which often lead to false negative diagnostic results, which occur both at the preanalytic stage and during nucleic acid amplification, including the interpretation of the obtained data. The viral load in humans was evaluated and assumptions were made about the expected number of viral particles in the studied oropharyngeal and nasopharyngeal samples. The list of diagnostic test systems approved for use in the Russian Federation for detecting SARS-CoV-2 with their brief characteristics is given. The necessity of simultaneous use of several targets in the coronavirus genome in one test system detected by probes with the same fluorochrome is noted, which on the one hand increases the probability of detection by increasing the signal, and on the other hand eliminates the false negative results that could occur in the case of mutations in the virus genome at the sites of annealing primers and hybridization probes.

scholarly journals Patient DNA cross-reactivity of the CDC SARS-CoV-2 extraction control leads to an inherent potential for false negative results

2020 ◽  
Author(s):  
Adam P. Rosebrock
Keyword(s):  
Reverse Transcription ◽  
False Negative ◽  
Rna Extraction ◽  
Cross Reactivity ◽  
Sample Collection ◽  
Negative Results ◽  
False Negative Results ◽  
Important Diagnostic Tool ◽  
Control And Prevention ◽  
Careful Handling

AbstractTesting for RNA viruses such as SARS-CoV-2 requires careful handling of inherently labile RNA during sample collection, clinical processing, and molecular analysis. Tests must include fail-safe controls that affirmatively report the presence of intact RNA and demonstrate success of all steps of the assay. A result of “no virus signal” is insufficient for clinical interpretation: controls must also say “The reaction worked as intended and would have found virus if present.” Unfortunately, a widely used test specified by the US Centers for Disease Control and Prevention (CDC) incorporates a control that does not perform as intended and claimed. Detecting SARS-CoV-2 with this assay requires both intact RNA and successful reverse transcription. The CDC-specified control does not require either of these, due to its inability to differentiate human genomic DNA from reverse-transcribed RNA. Patient DNA is copurified from nasopharyngeal swabs during clinically-approved RNA extraction and is sufficient to return an “extraction control success” signal using the CDC design. As such, this assay fails-unsafe: truly positive patient samples return a false-negative result of “no virus detected, control succeeded” following any of several readily-encountered mishaps. This problem affects tens-of-millions of patients worth of shipped assays, but many of these flawed reagents have not yet been used. There is an opportunity to improve this important diagnostic tool. As demonstrated here, a re-designed transcript-specific control correctly monitors sample collection, extraction, reverse transcription, and qPCR detection. This approach can be rapidly implemented and will help reduce truly positive patients from being incorrectly given the all-clear.One Sentence SummaryA widely-used COVID-19 diagnostic is mis-designed and generates false-negative results, dangerously confusing “No” with “Don’t know” – but it’s fixable

scholarly journals Clinical Performance of SARS-CoV-2 Molecular Testing

2020 ◽  
Author(s):  
Daniel A. Green ◽  
Jason Zucker ◽  
Lars F. Westblade ◽  
Susan Whittier ◽  
Hanna Rennert ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Severe Disease ◽  
False Negative ◽  
Molecular Testing ◽  
Repeat Testing ◽  
Clinical Sensitivity ◽  
Initial Testing ◽  
Molecular Assays ◽  
Negative Results ◽  
False Negative Results

AbstractMolecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the gold standard for diagnosis of coronavirus disease 2019 (COVID-19), but the test clinical performance is poorly understood. From 3/10/2020-5/1/2020 NewYork-Presbyterian laboratories performed 27,377 SARS-CoV-2 molecular assays from 22,338 patients. Repeat testing was performed in 3,432 patients, of which 2,413 had negative and 1,019 had positive first day results. Repeat-tested patients were more likely to be older, male, African-American or Hispanic, and to have severe disease. Among the patients with initially negative results, 18.6% became positive upon repeat-testing. Only 58.1% of any-time positive patients had a result of “detected” on the first test. The clinical sensitivity of COVID-19 molecular assays is estimated between 66.2 % and 95.6%, depending on the unknown number of false negative results in single-tested patients. Conversion to a negative result is unlikely to occur before 15 to 20 days after initial testing or 20-30 days after the onset of symptoms, with 50% conversion occurring at 28 days after initial testing. Forty-nine initially-positive patients converted to negative and then back to positive in subsequent days. Conversion from first day negative to positive results increased linearly with each day of testing, reaching 25% probability in 20 days. In summary, our study provides estimates of the clinical performance of SARS-CoV-2 molecular assays and suggests time frames for appropriate repeat testing, namely 15 to 20 days after a positive test and the same or next 2 days after a negative test in a patient with high suspicion for COVID-19.

Variables affecting laboratory diagnosis of acute rickettsial infection

2018 ◽  
Vol 39 (4) ◽  
pp. 220
Author(s):  
Cecilia Kato
Keyword(s):  
Molecular Detection ◽  
False Negative ◽  
Laboratory Diagnosis ◽  
Acute Stage ◽  
Detection Methods ◽  
Rickettsial Infection ◽  
Negative Results ◽  
Enhanced Sensitivity ◽  
False Negative Results ◽  
Antibody Titres

The reference standard for the confirmation of a recent rickettsial infection is by the observation of a four-fold or greater rise in antibody titres when testing paired acute and convalescent (two to four weeks after illness resolution) sera by serological assays (Figure 1). At the acute stage of illness, diagnosis is performed by molecular detection methods most effectively on DNA extracted from tissue biopsies (eschars, skin rash, and organs) or eschar swabs. Less invasive and more convenient samples such as blood and serum may also be used for detection; however, the low number of circulating bacteria raises the possibility of false negative results. Optimal sampling practices and enhanced sensitivity must therefore be considered in order to provide a more accurate laboratory diagnosis.

scholarly journals Performance of Indirect Immunoglobulin M (IgM) Serology Tests and IgM Capture Assays for Laboratory Diagnosis of Measles

2000 ◽  
Vol 38 (1) ◽  
pp. 99-104
Author(s):  
Samuel Ratnam ◽  
Graham Tipples ◽  
Carol Head ◽  
Micheline Fauvel ◽  
Margaret Fearon ◽  
...  
Keyword(s):  
Measles Virus ◽  
False Negative ◽  
Laboratory Diagnosis ◽  
Immunoglobulin M ◽  
Confirmatory Test ◽  
Serum Samples ◽  
Negative Results ◽  
Capture Assay ◽  
Specimen Collection ◽  
Control And Prevention

ABSTRACT As progress is made toward elimination of measles, the laboratory confirmation of measles becomes increasingly important. However, both false-positive and false-negative results can occur with the routinely used indirect measles immunoglobulin M (IgM) serology tests. The measles IgM capture assay is considered to be more specific, and therefore, its use is indicated for confirmatory testing, but its relative performance has not been fully assessed. Four commercial indirect measles IgM serology test kits (the Behring, Clark, Gull, and PanBio assays) and a commercial IgM capture assay (the Light Diagnostics assay) were evaluated for their abilities to detect measles virus-specific IgM antibody with a total of 308 serum samples from patients involved in a measles outbreak and with confirmed cases of measles and 454 samples from subjects without measles. The Centers for Disease Control and Prevention (CDC) IgM capture assay was also used in a part of the evaluation. Among the indirect assays, the overall sensitivities ranged from 82.8% (Clark assay) to 88.6% (Behring assay) and specificity ranged from 86.6% (PanBio assay) to 99.6% (Gull assay). These rates were 92.2 and 86.6%, respectively, for the Light Diagnostics capture assay and 87.0 and 94.8%, respectively, for the CDC capture assay. While the Light Diagnostics capture assay had the best detection rate (80%) with the acute-phase samples compared with those for the rest of the tests (CDC capture assay, 77%; Behring assay, 70%; Gull assay, 69%; PanBio assay, 58%; and Clark assay, 57%), all tests showed a significantly improved sensitivity in the range of 92% (Clark and PanBio assays) to 97% (Light Diagnostics and CDC capture assays) with the convalescent-phase samples, as expected. The best seropositivity rates (in the range of 92 to 100%) were observed with samples collected 6 to 14 days after the onset of symptoms. The Gull assay showed the highest positive predictive value (99.6%), followed by the Behring assay (97.8%) and the CDC capture assay (96.1%). Overall, the Gull and Behring assays were found to be as good as or better than the capture assays. In conclusion, laboratory diagnosis of measles based on IgM serology varies depending on the timing of specimen collection and the test used, and the case for the use of the IgM capture assay as the confirmatory test appears to be uncertain.

scholarly journals High-surety isothermal amplification and detection of SARS-CoV-2, including with crude enzymes

2020 ◽  
Author(s):  
Sanchita Bhadra ◽  
Timothy E. Riedel ◽  
Simren Lakhotia ◽  
Nicholas D. Tran ◽  
Andrew D. Ellington
Keyword(s):  
Point Of Care ◽  
False Negative ◽  
Human Saliva ◽  
Isothermal Amplification ◽  
Nucleic Acid Amplification ◽  
Target Sequence ◽  
One Pot ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain

ABSTRACTIsothermal nucleic acid amplification tests (iNAT), such as loop-mediated isothermal amplification (LAMP), are good alternatives to polymerase chain reaction (PCR)-based amplification assays, especially for point-of-care and low resource use, in part because they can be carried out with relatively simple instrumentation. However, iNATs can generate spurious amplicons, especially in the absence of target sequences, resulting in false positive results. This is especially true if signals are based on non-sequence-specific probes, such as intercalating dyes or pH changes. In addition, pathogens often prove to be moving, evolving targets, and can accumulate mutations that will lead to inefficient primer binding and thus false negative results. Internally redundant assays targeting different regions of the target sequence can help to reduce such false negatives. Here we describe rapid conversion of three previously described SARS-CoV-2 LAMP assays that relied on non-sequence-specific readout into assays that can be visually read using sequence-specific fluorogenic oligonucleotide strand exchange (OSD) probes. We evaluate one-pot operation of both individual and multiplex LAMP-OSD assays and demonstrate detection of SARS-CoV-2 virions in crude human saliva.

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