scholarly journals Real-time RT-PCR diagnostics of virus causing COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 52-63 ◽  
Author(s):  
E. V. Goncharova ◽  
A. E. Donnikov ◽  
V. V. Kadochnikova ◽  
S. A. Morozova ◽  
M. N. Boldyreva ◽  
...  
Keyword(s):  
Real Time ◽  
Sensitivity And Specificity ◽  
High Sensitivity ◽  
Medical Product ◽  
World Health ◽  
Differential Diagnostics ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Study Results ◽  
Pcr Diagnostics

Aim: the study was aimed to develop a reagent kit for the real-time RT-PCR diagnostics of virus causing COVID-19.Materials and Methods. Three target sites were chosen in the genome SARS-CoV-2. The testing included 220 samples, 48 artificially created positive samples (made from patients’ biomaterial) and 172 clinical samples (scrapes from nasal and pharyngeal cavities, bronchoalveolar lavage, expectoration, endotracheal/nasopharyngeal aspirate, feces, post-mortem material), obtained from two medical centers. Preliminary, the obtained biomaterial was analyzed with a reagent kit of comparison. The evaluation was performed with a confidential interval CI 95%. The calculation of CI for the sensitivity and specificity was made based on the distribution of χ2.Results. The authors developed a technology of novel coronavirus infection (COVID-19) real-time RT-PCR diagnostics for the application in practical healthcare and proposed the variants of testing at all the stages (preanalytical, analytical, and post-analytical, including automated results processing). The proposed reagent kit meets the requirements of the World Health Organization and the Ministry of Healthcare of the Russian Federation. The study results demonstrated high sensitivity and specificity. The sensitivity was 100% (95% CI) 95.6–100%; the specificity was 100% (95% CI) 96.7–100%.Conclusion. The proposed reagent kit was registered in the RF as a medical product; the registration certificate No. RZN 2020/9948 dated 01.04.2020. The application of the reagent kit in network laboratories will provide patients with access to testing for the virus causing COVID-19 and contribute to quick differential diagnostics, improvement of pandemic control, and accurate statistics on the spread of the virus. 

scholarly journals Evaluation of the performance of the COVID-19 rapid antigen tests in a tertiary level hospital in Bangladesh.

2021 ◽  
Author(s):  
Mohammad Jahidur Rahman Khan ◽  
Md. Shahadat Hossain ◽  
Samshad Jahan Shumu ◽  
Md. Selim Reza ◽  
Farzana Mim ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Detection Rate ◽  
High Sensitivity ◽  
Rt Pcr ◽  
College Hospital ◽  
Medical College ◽  
Qrt Pcr ◽  
Antigen Tests

Abstract Background: While the COVID-19 pandemic is a worldwide crisis, tests with high sensitivity and specificity are essential for identifying and managing COVID-19 patients. Globally, several rapid antigen tests RATs for COVID-19 have been developed, but their clinical efficacy has not been well established. This study aimed to evaluate the performance of several rapid antigen tests (RATs) to diagnose SARS-CoV-2 infection.Methods: This prospective observational study was conducted at Shaheed Suhrawardy Medical College hospital from February 2021 to April 2021 in Dhaka, Bangladesh. This study included the patients admitted in this hospital at the COVID-19 isolation unit or referred from the triage facility of the outdoor department of this hospital suspected as COVID-19 case. Two nasopharyngeal samples were collected simultaneously. one sample was used on the spot for the RAT. The other was sent to the adjacent Shaheed Suhrawardy Medical College COVID-19 RT-PCR laboratory for real-time reverse transcription-polymerase chain reaction (qRT-PCR). The performance of the RAT was evaluated using the results of qRT-PCR as a reference.Results: A total of 223 patients were included in this study, and the real-time RT-PCR detected SARS-CoV-2 in 84 (37.7%) patients. Of these 84 patients, 9 (10.7%) were asymptomatic. The overall sensitivity and specificity of RATs were 78.6% and 99.3%, respectively. The sensitivity was 81.3% in symptomatic cases and 55.6% in asymptomatic cases. False-negatives were observed in 18 patients, 3 of whom were asymptomatic and had a low viral load (cycle threshold (Ct) > 30). The detection rate of RATs was 100% when the Ct value was up to 24. The detection rate was 42.3% when the Ct was >29. The detection rate of RATs was 92.3% when the onset of symptoms was within three days. The detection rate was 33.3% when the onset of symptoms was >7 days.Conclusions: RATs for COVID-19 used in this study delivered an acceptable performance in patients with high viral load and within the first week of the onset of symptoms. They can be used as a supplementary method to RT-PCR for the diagnosis of COVID-19 patients.

scholarly journals Saving Resources: SARS-CoV-2 Diagnostics by Real-Time RT-PCR Using Reduced Reaction Volumes

Diseases ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 84
Author(s):  
Sabine Bock ◽  
Bernd Hoffmann ◽  
Martin Beer ◽  
Kerstin Wernike
Keyword(s):  
Real Time ◽  
Viral Genome ◽  
Virus Detection ◽  
World Health ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Reaction Volume ◽  
Reaction Volumes ◽  
Health Organization ◽  
The Individual

Since the beginning of 2020, the betacoronavirus SARS-CoV-2 is causing a global pandemic of an acute respiratory disease termed COVID-19. The diagnostics of the novel disease is primarily based on direct virus detection by RT-PCR; however, the availability of test kits may become a major bottleneck, when millions of tests are performed per week. To increase the flexibility of SARS-CoV-2 diagnostics, three real-time RT-PCR assays listed on the homepage of the World Health Organization were selected and investigated regarding their compatibility with three different RT-PCR kits. Furthermore, the reaction volume of the PCR chemistry was reduced up to half of the original protocol to make the individual reactions more cost- and resource-effective. When testing dilution series of culture-grown virus, nearly identical quantification cycle values (Cq) were obtained for all RT-PCR assay/chemistry combinations. Regarding the SARS-CoV-2 detection in clinical samples, agreeing results were obtained for all combinations for virus negative specimens and swabs containing high to medium viral genome loads. In cases of very low SARS-CoV-2 genome loads (Cq > 36), inconsistent results were observed, with some test runs scoring negative and some positive. However, no preference of a specific target within the viral genome (E, RdRp, or N) or of a certain chemistry was seen. In summary, a reduction of the reaction volume and the type of PCR chemistry did not influence the PCR sensitivity.

Detection of a novel bunyavirus associated with fever, thrombocytopenia and leukopenia syndrome in Henan Province, China, using real-time reverse transcription PCR

2013 ◽  
Vol 62 (7) ◽  
pp. 1060-1064 ◽  
Author(s):  
Xueyong Huang ◽  
Licheng Liu ◽  
Yanhua Du ◽  
Hongxia Ma ◽  
Yujiao Mu ◽  
...  
Keyword(s):  
Real Time ◽  
Reverse Transcription ◽  
High Sensitivity ◽  
Cross Reactivity ◽  
Henan Province ◽  
Clinical Samples ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Serum Samples ◽  
Reverse Transcription Pcr

A novel bunyavirus associated with fever, thrombocytopenia and leukopenia syndrome (FTLS) was discovered in Henan Province, China. Here, we report the development of an assay for this novel bunyavirus based on real-time reverse transcription PCR (RT-PCR). The assay exhibited high sensitivity and specificity without cross-reactivity towards 13 other viruses that cause similar symptoms. To evaluate the performance of this assay in detecting clinical samples, we analysed 261 serum samples from patients in Henan Province between 2007 and 2010. Of these samples, 91.95 % were bunyavirus positive. Compared with serological assays, the real-time PCR assay was much more sensitive in identifying infected patients 1 to 7 days after the onset of symptoms.

scholarly journals Comparison of an in house and a commercial real-time polymerase chain reaction targeting Toxoplasma gondii RE gene using various samples collected from patients in Turkey

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mert Döşkaya ◽  
Hüsnü Pullukçu ◽  
Muhammet Karakavuk ◽  
Esra Atalay Şahar ◽  
Mehmet Sezai Taşbakan ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Clinical Manifestations ◽  
High Sensitivity ◽  
Buffy Coat ◽  
Rt Pcr ◽  
Chain Reactions ◽  
Polymerase Chain ◽  
Pcr Test

Abstract Background Toxoplasma gondii is an opportunistic protozoan parasite that can infect all warm-blooded animals including humans and cause serious clinical manifestations. Toxoplasmosis can be diagnosed using histological, serological, and molecular methods. In this study, we aimed to detect T. gondii RE gene in various human samples by in house and commercial real time polymerase chain reactions. Methods A total of 38 suspected cases of toxoplasmosis [peripheral blood (n:12), amnion fluid (n:11), tissue (n:9), cerebrospinal fluid (n:5), and intraocular fluid (n:1)] were included to the study. An in house and a commercial RT-PCR were applied to investigate the T. gondii RE gene in these samples. Results The compatibility rate of the two tests was 94.7% (37/38). When the commercial RT-PCR kit was taken as reference, the sensitivity and specificity of in house RT-PCR test was 87.5 and 100%. When the in house RT-PCR test was taken as reference, the commercial RT-PCR kit has 100% sensitivity and 96.8% specificity. Incompatibility was detected in only in a buffy coat sample with high protein content. Conclusions Both the commercial and in house RT-PCR tests can be used to investigate T. gondii RE gene in various clinical specimens with their high sensitivity and specificity. In house RT-PCR assay can be favorable due to cost savings compared to using the commercial test.

scholarly journals EVALUATION OF ELEVEN IMMUNOCHROMATOGRAPHIC ASSAYS FOR SARS-CoV-2 DETECTION: INVESTIGATING DENGUE CROSS-REACTION

2020 ◽  
Author(s):  
Beatriz Araujo Oliveira ◽  
Lea Campos de Oliveira ◽  
Franciane Mendes de Oliveira ◽  
Geovana Maria Pereira ◽  
Regina Maia de Souza ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
High Sensitivity ◽  
Diagnostic Techniques ◽  
Cross Reactivity ◽  
Cross Reaction ◽  
List Type ◽  
Rt Pcr ◽  
Serum Samples ◽  
Igm Antibodies ◽  
Good Agreement

AbstractBackgroundCOVID-19 disease (Coronavirus disease 2019) caused by SARS-CoV-2 (Severe acute respiratory syndrome coronavirus 2) is widespread worldwide, affecting more than 11 million people globally (July 6th, 2020). Diagnostic techniques have been studied in order to contain the pandemic. Immunochromatographic (IC) assays are feasible and low cost alternative for monitoring the spread of COVID-19 in the population.MethodsHere we evaluate the sensitivity and specificity of eleven different immunochromatographic tests in 98 serum samples from confirmed cases of COVID-19 through RT-PCR and 100 negative serum samples from blood donors collected in February 2019. Considering the endemic situation of Dengue in Brazil, we also evaluated the cross-reactivity with Dengue using 20 serum samples from patients with confirmed diagnosis for Dengue collected in early 2019 through four different tests.ResultsOur results demonstrated agreement between immunochromatographic assays and RT-PCR, especially after 10 days since the onset of symptoms. The evaluation of IgG and IgM antibodies combined demonstrated a strong level of agreement (0.85) of IC assays and RT-PCR. It was observed cross-reactivity between Dengue and COVID-19 using four different IC assays for COVID-19 diagnosis. The specificity of IC assays to detected COVID-19 IgM antibodies using Dengue serum samples varied from 80% to 85%; the specificity of IgG detection was 100% and total antibody was 95%.ConclusionsWe found high sensitivity, specificity and good agreement of IC assays, especially after 10 days onset of symptoms. However, we detected cross-reactivity between Dengue and COVID-19 mainly with IgM antibodies demonstrating the need for better studies about diagnostic techniques for these diseases.HighlightsImmunochromatographic assays demonstrated high sensitivity and specificity and good agreement with the gold-standard RT-PCR;Increase in sensitivity and specificity of assays using samples collected after the 10th day of symptoms;Cross-reaction with Dengue serology in evaluation of IgM.

scholarly journals Ultrasensitive CRISPR-based diagnostic for field-applicable detection ofPlasmodiumspecies in symptomatic and asymptomatic malaria

2020 ◽  
Vol 117 (41) ◽  
pp. 25722-25731 ◽  
Author(s):  
Rose A. Lee ◽  
Helena De Puig ◽  
Peter Q. Nguyen ◽  
Nicolaas M. Angenent-Mari ◽  
Nina M. Donghia ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Sensitivity And Specificity ◽  
Parasite Density ◽  
Point Of Care ◽  
High Sensitivity ◽  
World Health ◽  
Ultrasensitive Detection ◽  
Asymptomatic Malaria ◽  
Radical Cure ◽  
Asymptomatic Carriers

Asymptomatic carriers ofPlasmodiumparasites hamper malaria control and eradication. Achieving malaria eradication requires ultrasensitive diagnostics for low parasite density infections (<100 parasites per microliter blood) that work in resource-limited settings (RLS). Sensitive point-of-care diagnostics are also lacking for nonfalciparum malaria, which is characterized by lower density infections and may require additional therapy for radical cure. Molecular methods, such as PCR, have high sensitivity and specificity, but remain high-complexity technologies impractical for RLS. Here we describe a CRISPR-based diagnostic for ultrasensitive detection and differentiation ofPlasmodium falciparum,Plasmodium vivax,Plasmodium ovale, andPlasmodium malariae, using the nucleic acid detection platform SHERLOCK (specific high-sensitivity enzymatic reporter unlocking). We present a streamlined, field-applicable, diagnostic comprised of a 10-min SHERLOCK parasite rapid extraction protocol, followed by SHERLOCK for 60 min forPlasmodiumspecies-specific detection via fluorescent or lateral flow strip readout. We optimized one-pot, lyophilized, isothermal assays with a simplified sample preparation method independent of nucleic acid extraction, and showed that these assays are capable of detection below two parasites per microliter blood, a limit of detection suggested by the World Health Organization. OurP. falciparumandP. vivaxassays exhibited 100% sensitivity and specificity on clinical samples (5P. falciparumand 10P. vivaxsamples). This work establishes a field-applicable diagnostic for ultrasensitive detection of asymptomatic carriers as well as a rapid point-of-care clinical diagnostic for nonfalciparum malaria species and low parasite densityP. falciparuminfections.

scholarly journals Epigenetic Markers for Molecular Detection of Prostate Cancer

2007 ◽  
Vol 23 (1-2) ◽  
pp. 31-41 ◽  
Author(s):  
Vera L. Costa ◽  
Rui Henrique ◽  
Carmen Jerónimo
Keyword(s):  
Prostate Cancer ◽  
Sensitivity And Specificity ◽  
Prostate Cancer Risk ◽  
High Sensitivity ◽  
Promoter Hypermethylation ◽  
Clinical Samples ◽  
Screening Methods ◽  
Tissue Samples ◽  
Age Related ◽  
Small Set

Prostate cancer is a highly prevalent malignancy, which is clinically silent but curable while organ-confined. Because available screening methods show poor sensitivity and specificity, the development of new molecular markers is warranted. Epigenetic alterations, mainly promoter hypermethylation of cancer-related genes, are common events in prostate cancer and might be used as cancer biomarkers. Moreover, the development of quantitative, high-throughput techniques to assess promoter methylation enabled the simultaneous screening of multiple clinical samples. From the numerous cancer-related genes hypermethylated in prostate cancer only a few proved to be strong candidates to become routine biomarkers. This small set of genes includesGSTP1,APC,RARβ2,Cyclin D2,MDR1, andPTGS2. Single and/or multigene analyses demonstrated the feasibility of detecting early prostate cancer, with high sensitivity and specificity, in body fluids (serum, plasma, urine, and ejaculates) and tissue samples. In addition, quantitative hypermethylation of several genes has been associated with clinicopathologic features of tumor aggressiveness, and also reported as independent prognostic factor for relapse. The identification of age-related methylation at specific loci and the differential frequency of methylation among ethnical groups, also provided interesting data linking methylation and prostate cancer risk. Although large trials are needed to validate these findings, the clinical use of these markers might be envisaged for the near future.

scholarly journals Description and Validation of a Novel Real-Time RT-PCR Enterovirus Assay

2008 ◽  
Vol 54 (2) ◽  
pp. 406-413 ◽  
Author(s):  
Weston C Hymas ◽  
Wade K Aldous ◽  
Edward W Taggart ◽  
Jeffery B Stevenson ◽  
David R Hillyard
Keyword(s):  
Sequence Analysis ◽  
Single Nucleotide Polymorphisms ◽  
Real Time ◽  
Clinical Samples ◽  
Nucleotide Polymorphisms ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Single Nucleotide ◽  
The Real ◽  
Nontranslated Region

Abstract Background: Enteroviruses are a leading cause of aseptic meningitis in adult and pediatric populations. We describe the development of a real-time RT-PCR assay that amplifies a small target in the 5′ nontranslated region upstream of the classical Rotbart enterovirus amplicon. The assay includes an RNA internal control and incorporates modified nucleotide chemistry. Methods: We evaluated the performance characteristics of this design and performed blinded parallel testing on clinical samples, comparing the results with a commercially available RT-PCR assay (Pan-Enterovirus OligoDetect kit) that uses an enzyme immunoassay–like plate end detection. Results: We tested 778 samples and found 14 discrepant samples between the 2 assays. Of these, the real-time assay detected 6 samples that were negative by the OligoDetect kit, 5 of which were confirmed as positive by sequence analysis using an alternative primer set. Eight discrepant samples were positive by the OligoDetect kit and real-time negative, with 6 confirmed by sequencing. Overall, detection rates of 97% and 96% were obtained for the OligoDetect kit and real-time assays, respectively. Sequence analysis revealed the presence of a number of single nucleotide polymorphisms in the targeted region. The comparative sensitivities of the 2 assays were equivalent, with the limit of detection for the real-time assay determined to be approximately 430 copies per milliliter in cerebrospinal fluid. Conclusions: This novel real-time enterovirus assay is a sensitive and suitable assay for routine clinical testing. The presence of single nucleotide polymorphisms can affect real-time PCR assays.

scholarly journals Performance Evaluation of Commercial Dengue Diagnostic Tests for Early Detection of Dengue in Clinical Samples

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Tuan Nur Akmalina Mat Jusoh ◽  
Rafidah Hanim Shueb
Keyword(s):  
Dengue Virus ◽  
Real Time ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Dengue Infection ◽  
Clinical Samples ◽  
Enzyme Linked Immunosorbent Assay ◽  
Rt Pcr ◽  
Serum Samples ◽  
Kappa Agreement

The shattering rise in dengue virus infections globally has created a need for an accurate and validated rapid diagnostic test for this virus. Rapid diagnostic test (RDT) and reverse transcription-polymerase chain reaction (RT-PCR) diagnostic detection are useful tools for diagnosis of early dengue infection. We prospectively evaluated the diagnostic performance of nonstructural 1 (NS1) RDT and real-time RT-PCR diagnostic kits in 86 patient serum samples. Thirty-six samples were positive for dengue NS1 antigen while the remaining 50 were negative when tested with enzyme-linked immunosorbent assay (ELISA). Commercially available RDTs for NS1 detection, RTK ProDetect™, and SD Bioline showed high sensitivity of 94% and 89%, respectively, compared with ELISA. GenoAmp® Trioplex Real-Time RT-PCR and RealStar® Dengue RT-PCR tests presented a comparable kappa agreement with 0.722. The result obtained from GenoAmp® Real-Time RT-PCR Dengue test showed that 14 samples harbored dengue virus type 1 (DENV-1), 8 samples harbored DENV-2, 2 samples harbored DENV-3, and 1 sample harbored DENV-4. 1 sample had a double infection with DENV-1 and DENV-2. The NS1 RDTs and real-time RT-PCR tests were found to be a useful diagnostic for early and rapid diagnosis of acute dengue and an excellent surveillance tool in our battle against dengue.

Sign in / Sign up

Export Citation Format

Share Document