scholarly journals Comparative Assessment of Sensitivity and Specificity of Rose Bengal Test and Modified In-house ELISA by using IS711 TaqMan Real Time PCR Assay as a Gold Standard for the Diagnosis of Bovine Brucellosis

2018 ◽  
Vol 11 (2) ◽  
pp. 951-957
Author(s):  
Amira M. Zakaria
Keyword(s):  
Positive Predictive Value ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Rose Bengal ◽  
Real Time Pcr ◽  
Predictive Value ◽  
Gold Standard ◽  
Bovine Brucellosis ◽  
Rt Pcr ◽  
Rose Bengal Test

Serological approaches such as Rose Bengal Test (RBT) and enzyme linked immunosorbent assay (ELISA) are common tests, however they are generally not sensitive or specific enough for diagnosis of Brucella because of cross-reactivity with different bacterial antigens. The work objected to evaluate the sensitivity and specificity of rose Bengal and modified in-house ELISA using IS711 real time PCR as a gold test to detect Brucella in calves sera. Two hundred and thirty (n=230) blood samples were collected from (2-3) years asymptomatic male calves in two Egyptian abattoirs. Rose Bengal test (RBT) and modified in-house ELISA were applied to determine the seroprevalence of brucellosis in abattoirs animals while quantitative Taqman real-time PCRs (RT-PCR) were implemented for the identification of Brucella genus. The overall prevalence of brucellosis was (53.9 %), (75.2 %) and (79.1 %) as determined by ELISA,RBT and RT- PCR assays respectively. Regarding statistical analysis of the reported data and considering real time PCR the gold standard, the RBT recorded a sensitivity of (79.12%) and a specificity of (39.58 %) with an accuracy of (70.87%). While (83.24%) was reported as positive predictive value and (33.33 %) as a negative predictive value. The sensitivity and specificity of ELISA were (55.49%) and (52.08 %) respectively while the accuracy was (54.78%). Positive predictive value and negative predictive value for ELISA were determined as (81.45%) and (23.58 %) respectively. RBT can be routinely used for diagnosis of Brucella as cost effective , more sensitive and accurate test than ELISA However, real time PCR is highly recommend as gold test for identification and differentiation of bovine brucellosis.

scholarly journals Performance comparison of two malaria rapid diagnostic test with real time polymerase chain reaction and gold standard of microscopy detection method

2020 ◽  
Author(s):  
Puspa Wardhani ◽  
Trieva Verawaty Butarbutar ◽  
Christophorus Oetama Adiatmaja ◽  
Amarensi Milka Betaubun ◽  
Nur Hamidah ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Diagnostic Test ◽  
Real Time Pcr ◽  
Predictive Value ◽  
Gold Standard ◽  
Detection Method ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Polymerase Chain

Background: The diagnostic test for malaria is mostly based on Rapid Diagnostic Test (RDT) and detection by microscopy. Polymerase Chain Reaction (PCR) is also a sensitive detection method that can be considered as a diagnostic tool. The outcome of malaria microscopy detection depends on the examiner's ability and experience. Some RDT has been distributed in Indonesia, which needs to be evaluated for their results. Objective: This study aimed to compare the performance of RightSign RDT and ScreenPlus RDT for detection of Plasmodium in human blood. We used specific real-time polymerase chain reaction abTESTMMalaria qPCRII) and gold standard of microscopy detection method to measure diagnostic efficiency. Methods: Blood specimens were evaluated using RightSign RDT, ScreenPlus RDT, Microscopy detection, and RT-PCR as the protocol described. The differences on specificity (Sp), sensitivity (Sn), positive predictive value (PPV), and negative predictive value (NPV) were analyzed using McNemar and Kruskal Wallis analysis. Results: A total of 105 subjects were recruited. Based on microscopy test, RightSign RDT had sensitivity, Specificity, PPV, NPV, 100%, 98%, 98.2%, 100%, respectively. ScreenPlus showed 100% sensitivity, 98% specificity, 98.2% PPV, 100% NPV. The sensitivity of both RDTs became lower (75%) and the specificity higher (100 %) when using real-time PCR. Both RDTs showed a 100% agreement. RT-PCR detected higher mix infection when compared to microscopy and RDTs. Conclusion: RightSign and ScreenPlus RDT have excellent performance when using microscopy detection as a gold standard. Real-time PCR method can be considered as a confirmation tool for malaria diagnosis.

scholarly journals Seroprevalence and Real-time PCR Detection of Brucellosis in Abattoirs Animals as a Potential Route of Infection in Egypt

2019 ◽  
Vol 1 (5) ◽  
Author(s):  
Amira Mohamed Zakaria ◽  
Salwa F. Ahmed ◽  
Mohamed S. Motawae
Keyword(s):  
Real Time ◽  
Rose Bengal ◽  
Real Time Pcr ◽  
Serological Test ◽  
Pcr Amplification ◽  
Cost Effective ◽  
Rt Pcr ◽  
Serum Samples ◽  
Molecular Approaches ◽  
Rose Bengal Test

Brucellosis is among the most common and economically serious zoonosis worldwide. Brucellosis in Egypt is an endemic problem among animals and humans. This work intended to evaluate the conventional serological and molecular approaches as a tool for studying the prevalence of brucellosis within abattoir’s animals in two large Egyptian provinces.  Two hundred and thirty (n=230) blood and serum samples were collected  from (2-3) years male calves in two Egyptian abattoirs. Rose Bengal  test (RBT) and modified in-house ELISA were  applied  to determine the seroprevalence of  Brucellosis  in abattoirs animals while quantitative Taqman real-time PCRs (RT-PCR) were implemented for the characterization of Brucella species. The overall prevalence of brucellosis  in the two proveinces was (53.9 %) , (75.2 %) and (79.1 %) as determined by ELISA ,RBT and RT- PCR assays respectively. Brucella DNA was successfully amplified from serum samples as well as blood. A total of n= 182 samples (79.1 %) were identified by real time PCR amplification for IS711 gene as Brucella genus, n= 118 (64.8 %) were reported as B. aborts while n= 85 (46.7 %) were reported as B. melitensis. N= 44 (24.17 %) from the collected samples comprised the two species of bacteria. This study endorses the application of rose Bengal test as a sensitive and cost effective  serological test for brucellosis and real-time PCR as a distinguishing tool to detect the causative agents. Our findings indicate a significantly high prevalence of Brucella  antibodies and DNA in blood and serum samples  which poses a crucial  threat to public health in Egypt.  

scholarly journals Impact of COVID-19 pre-test probability on positive predictive value of high cycle threshold SARS-CoV-2 real-time reverse transcription PCR test results

2021 ◽  
pp. 1-18
Author(s):  
Jonathan B. Gubbay ◽  
Heather Rilkoff ◽  
Heather L. Kristjanson ◽  
Jessica D. Forbes ◽  
Michelle Murti ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Real Time ◽  
Reverse Transcription ◽  
Predictive Value ◽  
Large Scale ◽  
Rdrp Gene ◽  
Nucleic Acid Detection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Test Probability

Abstract Objectives Performance characteristics of SARS-CoV-2 nucleic acid detection assays are understudied within contexts of low pre-test probability, including screening asymptomatic persons without epidemiological links to confirmed cases, or asymptomatic surveillance testing. SARS-CoV-2 detection without symptoms may represent presymptomatic or asymptomatic infection, resolved infection with persistent RNA shedding, or a false positive test. This study assessed positive predictive value of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (rRT-PCR) assays by retesting positive specimens from five pre-test probability groups ranging from high to low with an alternate assay. Methods A total of 122 rRT-PCR positive specimens collected from unique patients between March and July 2020 were retested using a laboratory-developed nested RT-PCR assay targeting the RNA-dependent RNA polymerase (RdRp) gene followed by Sanger sequencing. Results Significantly fewer (15.6%) positive results in the lowest pre-test probability group (facilities with institution-wide screening having ≤ 3 positive asymptomatic cases) were reproduced with the nested RdRp gene RT-PCR assay than in each of the four groups with higher pre-test probability (individual group range 50·0% to 85·0%). Conclusions Large-scale SARS-CoV-2 screening testing initiatives among low pre-test probability populations should be evaluated thoroughly prior to implementation given the risk of false positives and consequent potential for harm at the individual and population level.

ROLE OF MRI IN DIAGNOSIS OF ROTATOR CUFF TEAR ASSUMING ARTHROSCOPY AS GOLD STANDARD

2019 ◽  
Vol 3 (9) ◽  
Author(s):  
Dr. Chaturbhuj Prasad Swarnkar ◽  
Dr. Shiv Raj Meena
Keyword(s):  
Rotator Cuff ◽  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Shoulder Pain ◽  
Sensitivity And Specificity ◽  
Predictive Value ◽  
Gold Standard ◽  
Shoulder Joint ◽  
Rotator Cuff Tears ◽  
Arthroscopic Findings

Background- Rotator cuff tears are one of the most common causes of shoulder pain for which patients seek treatment. As in our daily work, the shoulder joint is the most frequently used, there is higher chance of having shoulder joint injury. The aim of the study is to compare the efficacy of MRI in diagnosing shoulder pathologies in comparison to arthroscopy, considering arthroscopy as the gold standard. Methods- 30 Patient with suspected rotator cuff injury patients, between 18-80 years of age was included in the study. MRI of the shoulder joint was done followed by shoulder arthroscopy. The data collected was analysed for the significant correlation between MRI of shoulder and arthroscopic findings by kappa statistics. Results- The accuracy of MRI in diagnosis of rotator cuff partial tears, was 90%, while sensitivity and specificity was 100.00%, 78.57% and positive predictive value was 84.21% and negative predictive value was 100.00% and accuracy of MRI in diagnosis of rotator cuff full tears, was 86.67%, while sensitivity and specificity was 63.64%, 100.00%) and positive predictive value was 100.00% and negative predictive value was 82.61% in our study. Conclusion- Our study demonstrates a high sensitivity and specificity for the MRI diagnosis of both partial and full thickness rotator cuff tears and good correlation with arthroscopic findings. Keywords: Rotator cuff, Shoulder pain, Arthroscopy, MRI.

scholarly journals Diagnosing SARS-CoV-2 with Antigen Testing, Transcription-Mediated Amplification and Real-Time PCR

2021 ◽  
Vol 10 (11) ◽  
pp. 2404
Author(s):  
Sascha Dierks ◽  
Oliver Bader ◽  
Julian Schwanbeck ◽  
Uwe Groß ◽  
Michael Weig ◽  
...  
Keyword(s):  
Real Time ◽  
Sensitivity And Specificity ◽  
Real Time Pcr ◽  
Gold Standard ◽  
Latent Class ◽  
Antigen Assay ◽  
Low Prevalence ◽  
Antigen Testing ◽  
Positive Results ◽  
Higher Sensitivity

This study was performed as a head-to-head comparison of the performance characteristics of (1) two SARS-CoV-2-specific rapid antigen assays with real-time PCR as gold standard as well as (2) a fully automated high-throughput transcription-mediated amplification (TMA) assay and real-time PCR in a latent class analysis-based test comparison without a gold standard with several hundred samples in a low prevalence “real world” setting. Recorded sensitivity and specificity of the NADAL and the LumiraDx antigen assays and the Hologic Aptima SARS-CoV-2 TMA assay were 0.1429 (0.0194, 0.5835), 0.7644 (0.7016, 0.8174), and 0.7157 (0, 1) as well as 0.4545 (0.2022, 0.7326), 0.9954 (0.9817, 0.9988), and 0.9997 (not estimable), respectively. Agreement kappa between the positive results of the two antigen-based assays was 0.060 (0.002, 0.167) and 0.659 (0.492, 0.825) for TMA and real-time PCR. Samples with low viral load as indicated by cycle threshold (Ct) values > 30 were generally missed by both antigen assays, while 1:10 pooling suggested higher sensitivity of TMA compared to real-time PCR. In conclusion, both sensitivity and specificity speak in favor of the use of the LumiraDx rather than the NADAL antigen assay, while TMA results are comparably as accurate as PCR, when applied in a low prevalence setting.

scholarly journals Challenges in laboratory diagnosis of Malaria in a low resource country among cases of acute febrile illness at tertiary care hospital in eastern Nepal: Comparative study on Conventional Vs Molecular approach

2020 ◽  
Author(s):  
Pragyan Dahal ◽  
Basudha Khanal ◽  
Keshav Rai ◽  
Vivek Kattel ◽  
Satish Yadav ◽  
...  
Keyword(s):  
Real Time ◽  
Sensitivity And Specificity ◽  
Malaria Elimination ◽  
Real Time Pcr ◽  
Gold Standard ◽  
Febrile Illness ◽  
Acute Febrile Illness ◽  
Low Resource ◽  
Elimination Programme ◽  
Low Resource Country

Abstract Background For ongoing malaria elimination programme, available methods like microscopy and rapid diagnostic test (RDT) are not able to detect all the cases of malaria in acute febrile illness. These methods are entirely dependent on the course of infection, parasite load and skilled technical resources thus the study was carried out to compare performance of microscopy and RDT which are commonly used in a low resource country along with reference to real-time PCR. Methods Altogether 52 blood samples collected from patients with acute febrile illness were tested by microscopy, RDT and real-time PCR. The results were compared in terms of sensitivity and specificity. Results The test results were as follows: 5.8% positivity by Microscopy, 13.5% positivity by RDT and 27% by real time PCR. Taking into consideration of PCR as a gold standard method microscopy showed 21.4% sensitivity and 100% specificity. Likewise, RDT results revealed 28.6% sensitivity and 92.1% specificity. Conclusion Despite of various diagnostic tools available, microscopy stills remains the gold standard for the diagnosis and RDT is the user friendly to execute the test under the tree, but our preliminary results emphasized the need to implement the test with the higher sensitivity and specificity in context of malaria elimination programme which could be another important opportunity to understand the parasite circulation in case of low endemic region. However, these results should be further verified with the large study cohort in order to document the submicroscopic infection.

scholarly journals Multiplex Real-Time PCR Assay for Simultaneous Identification of Neisseria gonorrhoeae and Its Ciprofloxacin Susceptibility Status

2017 ◽  
Vol 55 (11) ◽  
pp. 3201-3209 ◽  
Author(s):  
Sumudu R. Perera ◽  
Nurul H. Khan ◽  
Irene Martin ◽  
Ali Taheri ◽  
Rajinder P. Parti ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Real Time ◽  
Sensitivity And Specificity ◽  
Real Time Pcr ◽  
Genomic Dna ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Content Type ◽  
Simultaneous Identification ◽  
Susceptibility Status

ABSTRACTA real-time PCR (RT-PCR) assay was designed for the simultaneous identification ofNeisseria gonorrhoeaeand its ciprofloxacin susceptibility status. A SYBR green-based multiplex RT-PCR format was used; it comprised two different forward primers and a common reverse primer to detect single nucleotide polymorphisms (SNPs) ingyrAofN. gonorrhoeae. The primer pairs were evaluated for their sensitivity and specificity using genomic DNA from 254N. gonorrhoeaeisolates (82 were ciprofloxacin susceptible and 172 were ciprofloxacin resistant) and 23 non-N. gonorrhoeaespecies isolates. The performance of the primers was validated using genomic DNA from 100 differentN. gonorrhoeaeisolates (46 were ciprofloxacin susceptible and 54 were ciprofloxacin resistant) and 52 non-N. gonorrhoeaeisolates. The latter panel was revalidated by testing 99 (46 isolates were ciprofloxacin susceptible and 53 isolates were ciprofloxacin resistant) of theN. gonorrhoeaeisolates and 23 non-N. gonorrhoeaeisolates. These primers detectedN. gonorrhoeaeand its ciprofloxacin susceptibility status with over 99% sensitivity and specificity for all panels tested. This assay has the potential to be an inexpensive and rapid test for the simultaneous identification ofN. gonorrhoeaeand its ciprofloxacin susceptibility status.

scholarly journals The sensitivity and specificity of rapid diagnostic test for malaria parasite in comparison to slide microscopy as gold standard

10.17158/522 ◽  
2016 ◽  
Vol 19 (2) ◽  
Author(s):  
John Mark De Real
Keyword(s):  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Diagnostic Test ◽  
Rapid Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Predictive Value ◽  
Gold Standard ◽  
Malaria Parasite ◽  
High Sensitivity ◽  
Significant Difference

<p>The main objective of this study was to test the sensitivity and specificity of rapid diagnostic test for malaria parasite in comparison to slide microscopy as gold standard. Data were acquired from blood mass survey of malaria infection conducted in the community of Paquibato district, Davao City. There were 377 total participants examined through Rapid Diagnostic Test (RDT) and slide microscopy. Of the 377 participants tested, 16 (4.24%) of them were positive to Plasmodium falciparum and 68 (18.04%) were positive to Plasmodium vivax using slide microscopy. Of the 16 participants’ positive for P. faciparum, PfRDT (HRP-2) correctly identified 13 expressing 81.25% (low) sensitivity of the tool. Of the 68 participants’ positive for P. vivax, PvRDT (pLDH) correctly identified 65 expressing 95.59% (high) sensitivity. Both of the RDTs (HRP-2 and pLDH), however, attained 100% specificity. PfRDT (HRP-2) has a positive predictive value of 100% and a negative predictive value of 99.2%, likewise PvRDT (pLDH) has a positive predictive value of 100% and a negative predictive value of 99.04%, all in all, suggesting a high degree of reliability of SD BIOLINE Malaria Antigen P.f/P.v. the data showed no significant difference on the performance level of RDT, albeit less sensitive, compared to slide microscopy.</p><p><strong>Keywords:</strong> Health, malaria, sensitivity, specificity, HRP-2, pLDH, descriptive Davao City, Philippines.</p><div> </div>

scholarly journals Validitas Metode Real Time PCR GeneXpert pada Suspek TB Paru BTA Negatif di RSUD Dr. Doris Sylvanus

2021 ◽  
Vol 7 (1) ◽  
pp. 88-93
Author(s):  
Silvani Permatasari ◽  
Vani Vrenika ◽  
Florence Felicia ◽  
Malasinta Malasinta ◽  
Ria Eriani ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Real Time ◽  
Negative Predictive Value ◽  
Real Time Pcr ◽  
Predictive Value ◽  
Cross Sectional Study ◽  
Sputum Smear ◽  
Cross Sectional ◽  
Pulmonary Tb ◽  
Smear Negative

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Indonesia is one of the developing countries with high TB patients in the world. The most common detection used for TB diagnosis is sputum smear examination. Smear negative pulmonary TB still have a risk of infection and can develop into active. The GeneXpert molecular examination is a rapid diagnosis of TB by the real-time PCR method. The purpose of this study was to assess the validity of GeneXpert in smear-negative pulmonary TB compared to Lowenstein Jensen's culture. The design of this diagnostic test study is a cross-sectional study. The study was conducted on 40 people with smear-negative pulmonary TB suspect patients in Dr. Doris Sylvanus Regional Hospital. Sputum examination was performed with GeneXpert and compared with Lowenstein Jensen culture. The results of GeneXpert validity for diagnosing smear-negative pulmonary TB suspect are sensitivity 81.8%, specificity 96.5%, positive predictive value 90%, negative predictive value 93.3%, and accuracy 92.5%. It was concluded that GeneXpert has sensitivity, specificity, positive predictive value, negative predictive value, and high accuracy as a diagnostic tool in smear-negative pulmonary TB suspects.

Sign in / Sign up

Export Citation Format

Share Document