scholarly journals False-Negative Results of PCR Assay with Plasma of Patients with Severe Viral Hemorrhagic Fever

2002 ◽  
Vol 40 (11) ◽  
pp. 4394-4395 ◽  
Author(s):  
C. Drosten ◽  
M. Panning ◽  
S. Guenther ◽  
H. Schmitz
Keyword(s):  
False Negative ◽  
Hemorrhagic Fever ◽  
Viral Hemorrhagic Fever ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

scholarly journals Contrast of Real-Time Fluorescent PCR Methods for Detection of Escherichia coli O157:H7 and of Introducing an Internal Amplification Control

2019 ◽  
Vol 7 (8) ◽  
pp. 230 ◽  
Author(s):  
Zhao ◽  
Xia ◽  
Liu
Keyword(s):  
Real Time ◽  
Water Samples ◽  
False Negative ◽  
Internal Amplification Control ◽  
Pcr Assay ◽  
The Real ◽  
E Coli ◽  
Negative Results ◽  
False Negative Results ◽  
Fluorescent Pcr

Various constituents in food specimens can inhibit the PCR assay and lead to false-negative results. An internal amplification control was employed to monitor the presence of false-negative results in PCR amplification. In this study, the objectives were to compare the real-time PCR-based method by introducing a competitive internal amplification control (IAC) for the detection of Escherichia O157:H7 with respect to the specificity of the primers and probes, analytical sensitivity, and detection limits of contamination-simulated drinking water. Additionally, we optimized the real-time fluorescent PCR detection system for E. coli O157:H7. The specificity of primers and probes designed for the rfbE gene was evaluated using four kinds of bacterial strains, including E. coli O157:H7, Staphylococcus aureus, Salmonella and Listeria monocytogenes strains. The real time PCR assay unambiguously distinguished the E. coli O157:H7 strains after 16 cycles. Simultaneously, the lowest detection limit for E. coli O157:H7 in water samples introducing the IAC was 104 CFU/mL. The analytical sensitivity in water samples had no influence on the detection limit compared with that of pure cultures. The inclusion of an internal amplification control in the real-time PCR assay presented a positive IAC amplification signal in artificially simulated water samples. These results indicated that real-time fluorescent PCR combined with the IAC possessed good characteristics of stability, sensitivity, and specificity. Consequently, the adjusted methods have the potential to support the fast and sensitive detection of E. coli O157:H7, enabling accurate quantification and preventing false negative results in E. coli O157:H7 contaminated samples.

Development of a Polymerase Chain Reaction Assay for Detection of Burkholderia mallei, a Potent Biological Warfare Agent

2016 ◽  
Vol 66 (5) ◽  
pp. 458 ◽  
Author(s):  
Vijai Pal ◽  
Sandeep Singh ◽  
Arvind Kumar Tiwari ◽  
Y.K. Jaiswal ◽  
G.P. Rai
Keyword(s):  
Polymerase Chain Reaction ◽  
Tap Water ◽  
False Negative ◽  
Burkholderia Mallei ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Rapid Tool

Burkholderia mallei is the etiological agent of glanders, primarily a disease of equines. B. mallei is closely related to B. pseudomallei, the causative agent of melioidosis. Therefore, detection of B. mallei and its differentiation from B. pseudomallei, has always been troublesome. In present investigation, a B. mallei specific DNA sequence was identified by performing BLASTn search using ~3000 ORFs of B. mallei NCTC 10229. A polymerase chain reaction (PCR) assay with internal amplification control (IAC) was developed for detection of B. mallei and its differentiation from B. pseudomallei. The PCR assay could amplify a specific 224-bp fragment from all the six B. mallei strains used in the study, whereas other closely related organisms were tested negative. The detection limit of the assay was found to be 10 pg of purified DNA of B. mallei. Incorporation of IAC in the assay makes the results reliable as false negative results which may arise due to presence of PCR inhibitors, can be avoided. For validation, the assay was tested on tap water, Bengal gram and grass artificially spiked with B. mallei. The developed assay can be used as a simple and rapid tool for detection of B. mallei.

scholarly journals Strategy for Optimizing DNA Amplification in a Peripheral Blood PCR Assay Used for Diagnosis of Human Brucellosis

1998 ◽  
Vol 36 (9) ◽  
pp. 2443-2446 ◽  
Author(s):  
Pilar Morata ◽  
Maria Isabel Queipo-Ortuño ◽  
Juan de Dios Colmenero
Keyword(s):  
Peripheral Blood ◽  
False Negative ◽  
Dna Amplification ◽  
Human Brucellosis ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Total Dna ◽  
High Concentrations

We studied two of the possible factors which can interfere with specific DNA amplification in a peripheral-blood PCR assay used for the diagnosis of human brucellosis. We found that high concentrations of leukocyte DNA and heme compounds inhibit PCR. These inhibitors can be efficiently suppressed by increasing the number of washings to four or five and decreasing the amount of total DNA to 2 to 4 μg, thereby avoiding false-negative results.

scholarly journals Diagnosis of COVID-19 by Serology in Admitted Patients with Negative RT-PCR Assay

2021 ◽  
Author(s):  
Mitra Rezaei ◽  
Parvaneh Baghaei ◽  
Makan Sadr ◽  
Afshin Moniri ◽  
Abdolreza Babamahmoodi ◽  
...  
Keyword(s):  
Diagnostic Yield ◽  
Serological Test ◽  
False Negative ◽  
Diagnostic Methods ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serological Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain

Considering the increasing prevalence and burden of coronavirus disease 2019 (COVID-19) disease and false-negative results in routine reverse transcription-polymerase chain reaction (RT-PCR) tests, additional diagnostic methods are needed to diagnose active cases of this disease. This prospective study was conducted on patients, in whom clinical and radiological symptoms/signs were in favor of COVID-19 while their first PCR test was negative. Later on, a second RT-PCR was performed and serological evaluation was carried out and results were compared with each other. Out of 707 patients who had been referred to the hospital and were clinically and radiologically suspicious of disease, 137 patients with negative RT-PCR tests entered the study. RT-PCR assay became positive for the second time in 45 (32.8%). Anti-COVID-19 IgM and IgG antibodies were positive in 83 (60.6%) and 86 (62.8%) patients, respectively. Finally, it was determined that serological test was diagnostic in 73% of patients and the diagnostic yield of serology was significantly higher after the first week of illness (54.8% in the first week and 88% after that). Taking advantage of both serological tests and RT-PCR helps in diagnosing 83.9% of cases. Based on the present study, the serology may be useful as a complementary test and in parallel to RT-PCR assay for diagnosis of COVID-19 among admitted symptomatic cases.

scholarly journals Multitarget PCR Assay for Direct Detection of Penicillinase-Producing Neisseria gonorrhoeae for Enhanced Surveillance of Gonococcal Antimicrobial Resistance

2015 ◽  
Vol 53 (8) ◽  
pp. 2706-2708 ◽  
Author(s):  
Cameron Buckley ◽  
Ella Trembizki ◽  
Robert W. Baird ◽  
Marcus Chen ◽  
Basil Donovan ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Neisseria Gonorrhoeae ◽  
Direct Detection ◽  
False Negative ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Content Type ◽  
Negative Results ◽  
False Negative Results ◽  
Sequence Variations

A multitarget PCR was developed for the direct detection of penicillinase-producing Neisseria gonorrhoeae (PPNG). The assay was validated by testing 342 PPNG isolates and 415 clinical samples. The method is suitable for routine detection of PPNG strains. Its multitarget approach reduces the potential for false-negative results caused by sequence variations.

scholarly journals New Insight into Laboratory Tests and Imaging Modalities for Fast and Accurate Diagnosis of COVID-19: Alternative Suggestions for Routine RT-PCR and CT—A Literature Review

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Amir Khorasani ◽  
Amir Chegini ◽  
Arezoo Mirzaei
Keyword(s):  
False Negative ◽  
Imaging Modalities ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Magnetic Resonance Imaging Mri ◽  
Insight Into

The globally inimitable and unremitting outbreak of COVID-19 infection confirmed the emergency need for critical detection of human coronavirus infections. Laboratory diagnostic tests and imaging modalities are two test groups used for the detection of COVID-19. Nowadays, real-time polymerase chain reaction (RT-PCR) and computed tomography (CT) have been frequently utilized in the clinic. Some limitations that confront with these tests are false-negative results, tests redone for follow-up procedure, high cost, and unable to do for all patients. To overcome these limitations, modified and alternative tests must be considered. Among these tests, RdRp/Hel RT-PCR assay had the lowest diagnostic limitation and highest sensitivity and specificity for the detection of SARS-CoV-2 RNA in both respiratory tract and nonrespiratory tract clinical specimens. On the other hand, lung ultrasound (LUS) and magnetic resonance imaging (MRI) are CT-alternative imaging modalities for the management, screening, and follow-up of COVID-19 patients.

scholarly journals Performance Characteristics of BinaxNOW COVID-19 Antigen Card for Screening Asymptomatic Individuals in a University Setting

2021 ◽  
Author(s):  
Nkemakonam C Okoye ◽  
Adam P Barker ◽  
Kenneth Curtis ◽  
Richard R Orlandi ◽  
Emily A Snavely ◽  
...  
Keyword(s):  
False Negative ◽  
Analytical Sensitivity ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Viral Loads ◽  
University Of Utah ◽  
Negative Results ◽  
False Negative Results ◽  
Asymptomatic Individuals ◽  
Positive Agreement

We compared the performance of the Abbott BinaxNOW COVID-19 Antigen Card to a standard RT-PCR assay (ThermoFisher TaqPath COVID-19 Combo Kit) for the detection of SARS-CoV-2 in 2,645 asymptomatic students presenting for screening at the University of Utah. SARS-CoV-2 RNA was detected in 1.7% of the study participants by RT-PCR. BinaxNOW identified 24 infections but missed 21 infections that were detected by RT-PCR. The analytical sensitivity (positive agreement) and analytical specificity (negative agreement) for the BinaxNOW was 53.3% and 100%, respectively when compared against the RT-PCR assay. The median cycle threshold (Ct) value in the specimens that had concordant positive BinaxNOW antigen result was significantly lower compared to those that were discordant (Ct 17.6 vs. 29.6; p < 0.001). In individuals with presumably high viral loads (Ct < 23.0), a 95.8% positive agreement was observed between the RT-PCR assay and BinaxNOW. Due to the possibility of false negative results, caution must be taken when utilizing rapid antigen testing for screening asymptomatic individuals.

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