scholarly journals Nucleic Acid and Immunological Diagnostics for SARS-CoV-2: Processes, Platforms and Pitfalls

Diagnostics ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 866
Author(s):  
Avinash Premraj ◽  
Abi George Aleyas ◽  
Binita Nautiyal ◽  
Thaha J Rasool
Keyword(s):  
Sensitivity And Specificity ◽  
Early Stage ◽  
Control Strategies ◽  
False Negative ◽  
Primary Diagnosis ◽  
Test Methods ◽  
Molecular Technique ◽  
Negative Results ◽  
False Negative Results ◽  
Host Tissues

Accurate diagnosis at an early stage of infection is essential for the successful management of any contagious disease. The coronavirus disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus is a pandemic that has affected 214 countries affecting more than 37.4 million people causing 1.07 million deaths as of the second week of October 2020. The primary diagnosis of the infection is done either by the molecular technique of RT-qPCR by detecting portions of the RNA of the viral genome or through immunodiagnostic tests by detecting the viral proteins or the antibodies produced by the host. As the demand for the test increased rapidly many naive manufacturers entered the market with novel kits and more and more laboratories also entered the diagnostic arena making the test result more error-prone. There are serious debates globally and regionally on the sensitivity and specificity of these tests and about the overall accuracy and reliability of the tests for decision making on control strategies. The significance of the test is also complexed by the presence of asymptomatic carriers, re-occurrence of infection in cured patients as well as by the varied incubation periods of the infection and shifting of the viral location in the host tissues. In this paper, we review the techniques available for SARS-CoV-2 diagnosis and probable factors that can reduce the sensitivity and specificity of the different test methods currently in vogue. We also provide a checklist of factors to be considered to avoid fallacious practices to reduce false positive and false negative results by the clinical laboratories.

scholarly journals Nucleic Acid and Immunological Diagnostics for SARS-CoV-2: Processes, Platforms and Pitfalls

2020 ◽  
Author(s):  
Avinash Premraj ◽  
Abi George Aleyas ◽  
Binita Nautiyal ◽  
Thaha Jamal Rasool
Keyword(s):  
Sensitivity And Specificity ◽  
Early Stage ◽  
Control Strategies ◽  
False Negative ◽  
Primary Diagnosis ◽  
Test Methods ◽  
Molecular Technique ◽  
Negative Results ◽  
False Negative Results ◽  
Host Tissues

Accurate diagnosis at an early stage of infection is essential for the successful management of any contagious disease. The COVID-19, caused by the SARS-CoV-2 virus is a pandemic that has affected 214 countries affecting more than 30.8 million people causing 0.957 million deaths as of third week of September, 2020. The primary diagnosis of the infection is done either by the molecular technique of RT-qPCR by detecting portions of the RNA of the viral genome or through immunodiagnostic tests by detecting the viral proteins or the antibodies produced by the host. As the demand for the test increased rapidly many naive manufacturers entered the market with novel kits and more and more laboratories also entered the diagnostic arena making the test result more error-prone. There are serious debates globally and regionally on the sensitivity and specificity of these tests and about the overall accuracy and reliability of the tests for decision making on control strategies. The significance of the test is also complexed by the presence of asymptomatic carriers, re-occurrence of infection in cured patients as well as by the varied incubation periods of the infection and shifting of the viral location in the host tissues. In this paper, we review the techniques available for SARS-CoV-2 diagnosis and probable factors that can reduce the sensitivity and specificity of the different test methods currently in vogue. We also provide a check-list of factors to be taken care to avoid fallacious practices to reduce false positive and false negative results by the clinical laboratories

Pearls and Pitfalls of Interpretation in CT Colonography

2020 ◽  
Vol 71 (2) ◽  
pp. 140-148
Author(s):  
Michael Schonberger ◽  
Philippe Lefere ◽  
Abraham H. Dachman
Keyword(s):  
Computed Tomography ◽  
Sensitivity And Specificity ◽  
False Positive ◽  
Ct Colonography ◽  
False Negative ◽  
High Sensitivity ◽  
Negative Results ◽  
False Negative Results ◽  
The Common

The accuracy of computed tomography (CT) colonography (CTC) requires that the radiologist be well trained in the recognition of pitfalls of interpretation. In order to achieve a high sensitivity and specificity, the interpreting radiologist must be well versed in the causes of both false-positive and false-negative results. In this article, we review the common and uncommon pitfalls of interpretation in CTC.

scholarly journals Fluorometric detection of HIV-1 genome through use of an internal control, inosine-substituted primers, and microtiter plate format

1996 ◽  
Vol 42 (5) ◽  
pp. 696-703 ◽  
Author(s):  
B Gérard ◽  
C Peponnet ◽  
G Brunie ◽  
H Cavé ◽  
E Denamur ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Internal Control ◽  
False Negative ◽  
Enzymatic Reaction ◽  
Pcr Amplification ◽  
Microtiter Plate ◽  
Fluorometric Detection ◽  
Negative Results ◽  
False Negative Results ◽  
Hiv 1

Abstract We describe a PCR-based fluorometric assay for the detection of the HIV-1 genome. This technique consists of a reverse hybridization with oligonucleotide probes covalently coated onto a microtiter plate as a solid support. Several improvements to the PCR amplification and detection steps gave greater sensitivity and specificity for HIV-1 screening and resulted in a convenient and rapid technique. False-positive results were avoided by using uracyl DNA glycosylase. False-negative results from the presence of PCR inhibitors were detected by coamplifying an internal control with the viral sequence. False-negative results from viral genome variability were limited by using two pairs of primers and by incorporating inosine at the primer positions corresponding to viral polymorphic nucleotides. Furthermore, the hybridization buffer and enzymatic reaction were optimized to increase the assay's sensitivity. The sensitivity and specificity of the fluorometric detection were similar to those of radioisotopic oligonucleotide solution hybridization; however, hands-on time was reduced, and the use of radioactivity was eliminated. We have used this technique routinely on 115 samples and obtained 100% specificity and high sensitivity (only one false-negative result) according to viral culture and (or) serological status of the patients.

scholarly journals COVID-19 Testing – Impact of Prevalence, Sensitivity, and Specificity on Patient Risk and Cost

2020 ◽  
Author(s):  
Zoe C. Brooks ◽  
Saswati Das
Keyword(s):  
False Positive ◽  
False Negative ◽  
Test Methods ◽  
Antibody Testing ◽  
Patient Risk ◽  
Advantages And Disadvantages ◽  
Negative Results ◽  
False Negative Results ◽  
Antigen Tests ◽  
Positive Agreement

Since the beginning of the year 2020, the global healthcare system has been challenged by the threat of the SARS-COV 2 virus. Molecular, antigen, and antibody testing are the mainstay to identify infected patients and fight the virus. Molecular and antigen tests that detect the presence of the virus are relevant in the acute phase only. Serological assays detect antibodies to the Sars-CoV-2 virus in the recovering and recovered phase. Each testing methodology has its advantages and disadvantages. To evaluate the test methods, sensitivity (percent positive agreement - PPA) and specificity (percent negative agreement – PNA) are the most common metrics utilized, followed by the positive and negative predictive value (PPV and NPV), the probability that a positive or negative test result represents a true positive or negative patient. In this paper, we illustrate how patient risk and clinical costs are driven by false-positive and false-negative results. We demonstrate the value of reporting PFP (probability of false positive results), PFN (probability of false negative results), and costs to patients and healthcare. These risk metrics can be calculated from the risk drivers of PPA and PNA combined with estimates of prevalence, cost, and Reff number (people infected by one positive SARS COV-2).

FDG PET/CT and N0 mediastinal nodal status in early stage non-small cell lung cancer: A single institution retrospective experience.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 11570-11570
Author(s):  
Shashank Reddy Cingam ◽  
Sean Connor ◽  
Abhishek Harshad Patel ◽  
Samip R. Master ◽  
Amol Takalkar
Keyword(s):  
Fdg Pet ◽  
Early Stage ◽  
False Negative ◽  
Nodal Involvement ◽  
True Negative ◽  
Negative Results ◽  
Early Stage Nsclc ◽  
False Negative Results ◽  
Pet Ct ◽  
Fdg Pet Ct

11570 Background: The increasing use of CT and now low-dose screening CT scans for at-risk patients have led to increasing detection of lung cancer at early stages. FDG PET/CT is used as an adjunct to conventional imaging to assess loco-regional lymph node spread. However, there is a potential for false-negative results, especially in smaller lesions or early nodal involvement. The main objective of this study was to study the value of PET/CT scan to evaluate for true negative mediastinal nodes in patients with early stage NSCLC. Accurate determination of N0 status can have a significant impact on the cost-effectiveness and timely management of early stage NSCLC. Methods: Of a total of 404 patients with NSCLC managed at our facility between 2008 to 2015, 29 adult patients whose PET scan showed no or equivocal mediastinal nodal involvement and subsequently underwent surgical exploration of mediastinal lymph nodes were included in the study. Data variables that were collected included the cancer site, date of PET, node status on PET, type and date of surgery, cancer histology, and the tissue diagnosis of the sampled nodes. SAS software was used for the analysis of the data. Results: Of the 29 patients with N0 or equivocal nodes on FDG PET/CT, 7 (24.13%) had evidence of malignancy on biopsy of the surgically resected lymph nodes. No statistically significant differences were noted between the site of the neoplastic lesion, cancer histology, duration between the date of PET and the date of surgery in the true negative (TN) and false negative (FN) groups. The recurrence rate was higher in the FN group 60 % (3/5) compared to 21 % (4/19) in the TN group who had follow up for atleast 2 years. Conclusions: Our findings suggest incidence of false negative results of FDG PET/CT for evaluation of N0 nodes in early stage NSCLC is 24.13%. This is comparatively higher than false negatives rates with mediastinoscopy (5-10%) reported in other studies. Although our sample size is small, if confirmed, such a relatively high incidence of false negative results on FDG PET/CT for N0 disease supports the current recommendations for exploratory mediastinoscopy and/or surgery for definitive staging in early stage NSCLC.

scholarly journals Droplet Digital PCR – A Superior Complementary Technique for SARS-CoV-2 Detection

2020 ◽  
pp. 12-15
Author(s):  
I. M. Hussaini ◽  
S. Gide ◽  
B. Musa ◽  
M. A. Sulaiman ◽  
A. Usman
Keyword(s):  
Sensitivity And Specificity ◽  
False Negative ◽  
Standard Technique ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Reference Standard ◽  
Rt Pcr ◽  
Negative Results ◽  
False Negative Results ◽  
Current Reference Standard

Accurate and timely SARS-CoV-2 detection in suspected persons is crucial in the fight against its spread. Many techniques have been developed to meet up with the continuously growing demand, however some of these techniques lack the required accuracy, sensitivity and specificity. The current reference standard technique for SARS-CoV-2 detection is RT-PCR, but studies have shown that false-negative results are inevitable and data can be non-reproducible when samples and primers are not appropriately verified and validated. Droplet digital PCR (ddPCR) is a newly introduced technique that performs precise nucleic acid quantification. Researchers have evaluated the efficacy of ddPCR and the technique has shown promising results even in specimens with low viral load. ddPCR has shown increased accuracy, precision, sensitivity and specificity. Furthermore, it is less affected by annealing and amplification inhibitors. This suggests that ddPCR can be used as a complementary detection technique especially in convalescent cases.

scholarly journals Performance of seven commercial automated assays for the detection of low levels of anti-Toxoplasma IgG in French immunocompromised patients

Parasite ◽  
2019 ◽  
Vol 26 ◽  
pp. 51 ◽  
Author(s):  
Tiphaine Douet ◽  
Catherine Armengol ◽  
Elena Charpentier ◽  
Pamela Chauvin ◽  
Sophie Cassaing ◽  
...  
Keyword(s):  
High Risk ◽  
Sensitivity And Specificity ◽  
False Negative ◽  
Tissue Cyst ◽  
Grey Zone ◽  
Immunocompromised Patients ◽  
Negative Results ◽  
Acute Infections ◽  
False Negative Results ◽  
Low Levels

Background: Immunocompromised patients are at high risk for the development of severe toxoplasmosis from tissue cyst reactivation, the most frequently, or from recently acquired acute infections. Knowledge of serologic status is therefore crucial. Screening for toxoplasmosis is sometimes performed while patients are already immunocompromised and have a low or even undetectable IgG titer by routine automated enzyme immunoassays. The aim of this study was to assess the sensitivity and specificity of seven reagents for the detection of low levels of IgG. Sera from 354 patients were collected and analysed. Results: Elecsys® offered the best analytic performances, superior to those of Architect® and Platelia®, which were superior to those of Access II® and TGS TA®. Vidas II® and Liaison II® reagents exhibited poor analytical performances in this cohort. For Elecsys®, Platelia® and Architect®, new thresholds for the grey zone and positive zone have been defined to improve the sensitivity of these reagents while maintaining excellent specificity. Conclusions: Commercialized assays for toxoplasmosis screening are not suitable for IgG low-level detection in patients without adapting the supplier thresholds to avoid false negative results and risk generalized toxoplasmosis.

scholarly journals COVID-19—Clinical Relevance of a Negative RT-PCR SARS-CoV-2 Test

2020 ◽  
Vol 2020 (1) ◽  
pp. 1
Author(s):  
Roxana Jurca ◽  
Camil Mihuța ◽  
Emanuela Tudorache ◽  
Diana Manolescu ◽  
Cristian Oancea
Keyword(s):  
False Negative ◽  
Test Methods ◽  
Rt Pcr ◽  
Clinical Criteria ◽  
Reactive Protein ◽  
Negative Results ◽  
Systemic Corticosteroids ◽  
False Negative Results ◽  
Chest X Ray ◽  
Diagnosis Accuracy

(1) Background: In the current clinical practice of the COVID-19 infection, the focus should not be placed on the positive RT-PCR results, but rather on the epidemiological, clinical, and imaging aspects specific to the disease. (2) Case Report: We present the case of a 34-year-old female, who had contacts with both her parents, both of whom were confirmed to have SARS-CoV-2 infection by RT-PCR testing. She presented for about one week symptoms suggestive of COVID-19 infection, determining her to repeatedly go to the emergency room, where she had three negative SARS-CoV-2 RT-PCR tests. The blood tests revealed leukopenia with lymphocytopenia, with increased lactate dehydrogenase (LDH) and C-reactive protein (CRP). Moreover, the chest X-ray showed modifications specific for COVID-19, and the diagnosis of COVID-19 was set. Drug treatment with hydroxychloroquine, azithromycin, cephalosporins, systemic corticosteroids, anticoagulants, bronchodilators, and interleukin-6 inhibitors was initiated, together with oxygen therapy. (3) Discussion: SARS-CoV-2 RT-PCR testing may give false negative results due to inadequate biological sampling, or to the accuracy of the test methods. A significant contribution to the diagnosis is made by the specific computed tomography (CT) criteria of COVID-19. (4) Conclusions: A priority for COVID-19 diagnosis accuracy is epidemiological investigation, together with clinical criteria and CT imaging, even in the presence of a negative RT-PCR test.

scholarly journals The MTB/MDR ELITe MGB® Kit: Performance Assessment for Pulmonary, Extra-Pulmonary, and Resistant Tuberculosis Diagnosis, and Integration in the Laboratory Workflow of a French Center

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 176
Author(s):  
Elisabeth Hodille ◽  
Charlotte Genestet ◽  
Thomas Delque ◽  
Luna Ruffel ◽  
Yvonne Benito ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Antimicrobial Susceptibility ◽  
False Negative ◽  
Nucleic Acid Amplification ◽  
Negative Results ◽  
Resistant Tuberculosis ◽  
False Negative Results ◽  
Extra Pulmonary ◽  
Easy Integration ◽  
Laboratory Workflow

A rapid and reliable diagnostic for tuberculosis, including the detection of both rifampicin (RIF) and isoniazid (INH) resistance, is essential for appropriate patient care. Nucleic acid amplification tests are a fast alternative to methods based on Mycobacterium tuberculosis complex (MTB) cultures. Thus, the performance of the MDR/MTB ELITe MGB® Kit on the ELITe InGenius® platform was retrospectively evaluated for MTB detection on pulmonary and extra-pulmonary samples and for RIF/INH resistance detection on MTB strains. The sensitivity and specificity of the kit for MTB detection compared to the MTB culture were 80.0% and 100.0%, respectively. For the antimicrobial susceptibility prediction, the agreement with phenotypic antimicrobial susceptibility testing (AST) was 92.0%. For RIF, the sensitivity was 100.0% and the specificity was 95.5%. For INH, the sensitivity and specificity were 75.0% and 100.0%, respectively. A single RIF false-positive result was obtained for a strain with a low level of RIF resistance that was not detected by phenotypic AST, but carrying a rpoB L452P mutation. INH false-negative results (3) were due to mutations on the katG gene that were not probed by the test. Overall, the MTB/MDR ELITe MGB® Kit presents a strong performance for MTB detection and for the detection of both RIF and INH resistance, with an easy integration in laboratory workflow thanks to its fully automatized system.

scholarly journals Association Between Early Stage Colon Neoplasms and False-negative Results From the Fecal Immunochemical Test

2013 ◽  
Vol 11 (7) ◽  
pp. 832-838.e2 ◽  
Author(s):  
Han–Mo Chiu ◽  
Yi–Chia Lee ◽  
Chia–Hung Tu ◽  
Chien–Chuan Chen ◽  
Ping–Huei Tseng ◽  
...  
Keyword(s):  
Early Stage ◽  
False Negative ◽  
Fecal Immunochemical Test ◽  
Colon Neoplasms ◽  
Negative Results ◽  
False Negative Results ◽  
Immunochemical Test
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