scholarly journals A Comparison of Ligase Chain Reaction to Polymerase Chain Reaction in the Detection ofChlamydia trachomatisEndocervical Infections

1998 ◽  
Vol 6 (2) ◽  
pp. 57-60 ◽  
Author(s):  
J. D. Davis ◽  
P. K. Riley ◽  
C. W. Peters ◽  
K. H. Rand

Objective:To compare the reliability of ligase chain reaction (LCR) to polymerase chain reaction (PCR) in detectingChlamydia trachomatisendocervical infections.Methods:We conducted a prospective study of 486 patients at risk for chlamydial infection of the endocervix. We obtained two endocervical specimens from each patient and used LCR and PCR to detectC. trachomatis. Discrepant results between the two techniques were resolved by repeat testing and by testing for the major outer membrane protein (MOMP) gene, if necessary. We determined the sensitivity, specificity, positive predictive value, and negative predictive value for each test, using concordant results or MOMP gene results as the “gold standard”.Results:Of the 486 patients, 42 (8.6%) had evidence ofC. trachomatisinfection after resolution of discrepant results. Of the 42 true positive specimens, 41 were positive by initial LCR and 38 were positive by initial PCR. Of the 444 true negative specimens, none had a positive initial LCR result, while 2 had a positive initial PCR test. Therefore, compared to the gold standard, LCR had a sensitivity of 97.6% and specificity of 100%, while PCR had a sensitivity of 90% and a specificity of 99.5%. The positive and negative predictive values of LCR were 100% and 99.8%, respectively. PCR had a positive predictive value of 95% and a negative predictive value of 99.1%. The difference in sensitivity of LCR versus PCR was not statistically significant (P= .125).Conclusion:LCR and PCR perform equally well in detectingC. trachomatisendocervical infections.

2013 ◽  
Vol 24 (3) ◽  
pp. e69-e74 ◽  
Author(s):  
PD Andrade ◽  
MT Fioravanti ◽  
EBV Anjos ◽  
C De Oliveira ◽  
DM Albuquerque ◽  
...  

BACKGROUND: Human cytomegalovirus is an important cause of morbidity and mortality in immunocompromised patients. Qualitative polymerase chain reaction (PCR) has proven to be a sensitive and effective technique in defining active cytomegalovirus infection, in addition to having low cost and being a useful test for situations in which there is no need for quantification. Real-time PCR has the advantage of quantification; however, the high cost of this methodology makes it impractical for routine use.OBJECTIVE: To apply a nested PCR assay to serum (sPCR) and to evaluate its efficiency to diagnose active cytomegalovirus infection compared with PCR of peripheral blood leukocytes (L-PCR).METHODS: Samples of 37 patients were prospectively evaluated. An internal control was created and applied to sPCR to exclude false-negative results.RESULTS: In total, 21 patients (57%) developed active cytomegalovirus infection. After analyzing the two methods for the diagnosis of active infection, higher sensitivity and negative predictive value of the L-PCR versus sPCR (100% versus 62%), and higher specificity and positive predictive value of sPCR versus L-PCR (81% versus 50% and 72%, respectively) were observed. Discordant results were observed in 11 patients who were L-PCR-positive but sPCR-negative for active cytomegalovirus infection, five of whom developed clinical symptoms of cytomegalovirus. Clinical symptoms were observed in 14 patients, 12 of whom were diagnosed with active infection by nested L-PCR (P=0.007) and seven by nested sPCR (P=0.02). Higher specificity and a positive predictive value for sPCR were observed.CONCLUSION: Nested L-PCR and sPCR were considered to be complementary methods for the diagnosis and management of symptomatic cytomegalovirus infection.


Author(s):  
Puspa Wardhani ◽  
Trieva Verawaty Butarbutar ◽  
Christophorus Oetama Adiatmaja ◽  
Amarensi Milka Betaubun ◽  
Nur Hamidah ◽  
...  

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.


2020 ◽  
Author(s):  
Diana Martínez-Ruíz ◽  
Luis Gabriel Parra-Lara ◽  
Fernando Rosso

Abstract BackgroundClostridium difficile infection (CDI) is commonly diagnosed with the polymerase chain reaction (PCR), but this test finds a high percentage of false positives, so their use and interpretation in CDI is a challenge in the clinical practice. That is why it is necessary to define an algorithm to optimize the use of PCR that considers clinical characteristics to classify patients with diarrhea as CDI or without CDI. ObjectiveTo identify a predictive algorithm with the clinical features that best classify patients with CDI vs. without CDI, to help physicians in making decisions to request PCR. Materials and methodsA case-control study was conducted at Fundación Valle del Lili. The population was inpatients between 2012 and 2016, with 18 or more years, and diarrhea, abdominal pain, or other nonspecific gastrointestinal symptoms who underwent PCR. Cases were defined as patients with positive PCR for C. difficile and as controls patients with negative PCR for C. difficile. Predictive algorithms to classify patients was constructed using a classification tree, classification and regression tree (CART). ResultsA total of 149 patients were included (48 cases with positive PCR and 99 controls with negative PCR). The CART has a high capacity to classify patients with a negative PCR correctly. It includes variables about the history of antibiotics use, the use of proton-pump inhibitor, the use of ranitidine, and the use of antifungal drugs. The CART showed sensitivity 64.6%, specificity 85.8%, positive predictive value 68.8%, negative predictive value 83.3%. and AUC 79.7%.DiscussionCART had good specificity and a high negative predictive value; it could be considered as an algorithm to identify conditions that indicate when it is not necessary to perform a PCR test in a patient symptom of CDI.


1999 ◽  
Vol 37 (9) ◽  
pp. 3072-3073 ◽  
Author(s):  
K. B. Waites ◽  
K. R. Smith ◽  
M. A. Crum ◽  
R. D. Hockett ◽  
A. H. Wells ◽  
...  

Ligase chain reaction (LCR) was compared with ACCESS immunoassay for detection of chlamydial infections in females. Despite efforts to improve ACCESS performance by evaluation of specimens that were in the test performance “grey zone,” LCR remained more sensitive and was less expensive to perform. ACCESS had a sensitivity of 83.9%, a specificity of 99.7%, a positive predictive value of 96.3%, and a negative predictive value of 98.5%.


2016 ◽  
Vol 20 (1) ◽  
pp. 28-33
Author(s):  
Yogaraje GC Varadaiah ◽  
Raghu K Chinnappa ◽  
Rakshitha M Nagaraj ◽  
Thejashwini NA ◽  
Robinson K Samuel ◽  
...  

ABSTRACT Introduction The poor sensitivity of conventional smear microscopy and the delay in obtaining Mycobacterium culture results prevent the early diagnosis of Myobacterium tuberculosis (MTB). By using nucleic acid amplification techniques like polymerase chain reaction (PCR), one may be able to diagnose the disease on the day of arrival of specimen in the laboratory. The present study aimed to evaluate the applicability of the nested-PCR (nPCR) technique as a rapid and direct molecular method for the diagnosis of M. tuberculosis in sputum specimens of patients whose sputum smear was acid-fast bacilli (AFB) negative using heat shock protein (hsp65) as the gene target. Materials and methods Early morning sputum samples were collected in sterile containers respectively from about 40 suspected patients of pulmonary tuberculosis, attending the outpatient units of JSS Medical College and PKTB Hospital, Mysore and from 20 age and sex-matched healthy controls. Sputum samples were decontaminated by modified Petroff's method and DNA was isolated using QIAGEN DNA extraction kit. The nPCR was carried out for the detection of MTB using the target gene hsp65. Results Nested-PCR showed specific amplification (165bp) of M. tuberculosis in 18 out of 20 sputum AFB positive samples and 9 out of 20 AFB negative samples. None of the healthy controls showed any amplification with nPCR. The nPCR when compared to that of Ziehl-Neelsen staining had a sensitivity of 90%, specificity of 77.5%, positive predictive value (PPV) of 66.6%, and negative predictive value (NPV) of 93.9%. The percentage of false positive was 33.3% and percentage of false negative was 6.1%. Conclusion The detection of M. tuberculosis with nPCR in smear negative patients provides the bacteriological data 4 to 8 weeks earlier. A molecular approach, based on the amplification of hsp65 gene by nPCR, showed that there is high probability of the disease being absent when the test is negative because of the high negative predictive value (NPV). How to cite this article Varadaiah YGC, Prashant A, Chinnappa RK, Nagaraj RM, Thejashwini, Samuel RK, Devegowda D, Vishwanath P. Evaluation of Nested Polymerase Chain Reaction targeting hsp65 of Mycobacterium tuberculosis for the Detection of Organism in the Sputum Samples. Indian J Med Biochem 2016;1(1):28-33.


2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Rilvia Mona Cambey

Abstract: Malaria disease is one of the priority of the health programs because it affects the Human Development Index, which result in icreased mortality among infants, toddlers, pregnant woman and adults. WHO noted that in 2010 there was 219 million cases of malaria with mortality rate of 660.0000 annually.Until now, the microscopic method who has many limitation is  still the gold standard in malaria examination. On other side, Polymerase Chain Reaction which proved accurate as it can identify Plasmodium up to the stage of DNA is not yet use as routine examination of Malaria Disease. The purpose of this study was compare the sensitivity and specificity of detection Plasmodium spp. using the gold standard Microscopic examination (thin blood smear)  with the Polymerase Chain Reaction (PCR) method. The design of this study is Diagnostic Test with a sample of 30 people whoose blood was drawn in malaria patients who come to the RSU Budi Mulia Bitung and RS Manembo-nembo since September 2013- Januari 2014. Blood taken made into a thin blood smear  then extracted and proceeded  to PCR. Then from the result of both test, diagnostic test applied to determine the level of sensitivity,spesificity,positif predictive value, and negatif predictive value. Results: The level of sensitivity of the PCR was 100%,specificity 60%, positif predictive value 83,33&, and negatif predictive value 100%.Conclusion: PCR is more accurate in determining the plasmodium species and produce fewer errors than the diagnosis of Microscopic examination thin blood smears. Keywords: Microscopic Examination, Thin blood smear, Polymerase Chain Reaction (PCR), sensitivity, specificity   Abstrak: Malaria merupakan salah satu prioritas program kesehatan karena mempengaruhi Human Development Index yang mengakibatkan meningkatnya angka kematian pada bayi, balita, ibu hamil, dan orang-orang dewasa. WHO mencatat pada tahun 2010 terdapat 219 juta kasus malaria dengan angka kematian 660.000 setiap tahunnya. Sampai sekarang ini, metode mikroskopis yang memiliki banyak keterbatasan masih menjadi standar baku emas dalam pemeriksaan malaria. Dilain pihak Polymerase Chain Reaction yang terbukti akurat karena dapat mengidentifikasi plasmodium sampai pada tahap DNA belum dijadikan pemeriksaan rutin penyakit malaria.Tujuan : Penelitian ini membandingkan tingkat sensitivitas dan spesifisitas deteksi Plasmodium spp menggunakan pemeriksaan baku emas yaitu mikroskopik sediaan darah tipis dengan Polymerase Chain Reaction (PCR). Metode : Penelitian ini merupakan penelitian uji diagnostik dengan sampel sejumlah 30 orang yang darahnya diambil  pada pasien malaria yang datang ke RSU Budi Mulia dan RS Manembo-nembo sejak bulan September 2013 - Januari 2014. Darah yang diambil, dibuat menjadi hapusan darah tipis, kemudian diekstraksi dan di lanjutkan ke pemeriksaan PCR. Kemudian dari hasil kedua pemeriksaan, dilakukan uji diagnostik untuk mengetahui tingkat sensitivitas, spesifisitas, nilai duga positif dan nilai duga negatif. Hasil: Tingkat sensitivitas PCR sebesar 100%, spesifisitas sebesar 60%, nilai duga positif sebesar 83,33% dan nilai duga negatif sebesar 100%.Simpulan: PCR lebih akurat dalam menentukan spesies plasmodium dan lebih sedikit menghasilkan kesalahan diagnosis daripada pemeriksaan mikroskopik sediaan darah tipis.Kata Kunci: Pemeriksaan Mikroskopis, Sediaan Darah Tipis,Polymerase Chain Reaction (PCR), Sensitivitas, Spesifisitas.


Author(s):  
Museyaroh Museyaroh ◽  
Puspa Wardhani ◽  
Aryati Aryati

In December 2019, an outbreak of acute pneumonia occurred in Wuhan, China. The disease was transmitted betweenhumans through droplets (coughing or sneezing) of infected patients, causing this outbreak to spread rapidly in variouscountries in the world, including Indonesia. On February 11, 2020, WHO announced the pneumonia was caused byCoronavirus Disease 2019 (COVID-19), which was caused by a new type of Coronavirus, the SARS-CoV-2. A rapid andaccurate diagnosis is critical for the control of the COVID-19 outbreak. The widely used test is a serology-based test thatdetects the presence of SARS-CoV-2 IgM/IgG antibodies in the patient's body. One of the methods used for this test isChemiluminescent Immunoassay (CLIA). This study aimed to determine the reliability of CLIA. The study was conductedfrom August to September 2020. The number of samples was 63 patients' serum. Polymerase chain reaction examination atHusada Utama Hospital, Surabaya, revealed that 21 patients were confirmed positive for COVID-19 with positive PCRresults, and 42 patients were healthy with negative COVID-19 results. The results showed that IgM had a diagnosticsensitivity of 85.7%, diagnostic specificity of 92.8%, a positive predictive value of 85.7%, a negative predictive value of 92.8%,and accuracy of 90.4%. In comparison, IgG had a diagnostic sensitivity of 90.4%, diagnostic specificity of 90.4%, a positivepredictive value of 82.6%, a negative predictive value of 90.5%, and accuracy of 90.4%. In conclusion, IgG has a highersensitivity than IgM, while IgM had higher specificity, positive predictive value, and negative predictive value than IgG.However, the positive, negative predictive value and efficiency values were the same for IgM and IgG.


Sexual Health ◽  
2013 ◽  
Vol 10 (4) ◽  
pp. 387 ◽  
Author(s):  
Arlo Upton ◽  
Janet Wilson ◽  
Liselle Bissessor

We introduced polymerase chain reaction (PCR) testing for Neisseria gonorrhoeae (NG) on the Cobas 4800 CT/NG assay for all samples received with a Chlamdyia trachomatis request in March 2012. From 1 March 2012 to 30 June 2012, all PCR-positive/culture-negative specimens had additional testing at another assay. A total of 40053 tests were performed. The estimated specificity and positive predictive value were 99.9% and 97.1%, respectively; thus routine additional testing is not required.


2020 ◽  
Author(s):  
Shigeta Miyake ◽  
Takuma Higurashi ◽  
Takashi Jono ◽  
Taisuke Akimoto ◽  
Fumihiro Ogawa ◽  
...  

Abstract Background: The Coronavirus disease 2019 pandemic continues to spread worldwide. Because of the absence of reliable rapid diagnostic systems, patients with symptoms of Coronavirus disease 2019 are treated as suspected of the disease. Use of computed tomography findings in Coronavirus disease 2019 are expected to be a reasonable method for triaging patients, and computed tomography-first triage strategies have been proposed. However, clinical evaluation of a computed tomography-first triage protocol is lacking.The aim of this study is to investigate the real-world efficacy and limitations of a computed tomography-first triage strategy in patients with suspected Coronavirus disease 2019.Methods: This was a single-center cohort study evaluating outpatients with fever who received medical examination at Yokohama City University Hospital, prospectively registered between 9 February and 5 May 2020. We treated according to the computed tomography-first triage protocol. The primary outcome was efficacy of the computed tomography-first triage protocol for patients with fever in an outpatient clinic. Efficacy of the computed tomography-first triage protocol for outpatients with fever was evaluated using sensitivity, specificity, positive predictive value, and negative predictive value. We conducted additional analyses of the isolation time of feverish outpatients and final diagnoses.Results: In total, 108 consecutive outpatients with fever were examined at our hospital. Using the computed tomography-first triage protocol, 48 (44.9%) patients were classified as suspected Coronavirus disease 2019. Nine patients (18.8%) in this group were positive for severe acute respiratory syndrome coronavirus 2 using polymerase chain reaction; no patients in the group considered less likely to have Coronavirus disease 2019 tested positive for the virus. The sensitivity, specificity, positive predictive value, and negative predictive value of our computed tomography-first triage protocol for Coronavirus disease 2019 were 100%, 60.2%, 18.8%, and 100%, respectively. The protocol significantly shortened the duration of isolation for the not-suspected versus the suspected group (70.5 vs. 1037.0 minutes, P < .001). Conclusions: Our computed tomography-first triage protocol was acceptable for screening patients with suspected Coronavirus disease 2019. This protocol will be helpful for appropriate triage, especially in areas where polymerase chain reaction is inadequate.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fatemeh Khatami ◽  
Mohammad Saatchi ◽  
Seyed Saeed Tamehri Zadeh ◽  
Zahra Sadat Aghamir ◽  
Alireza Namazi Shabestari ◽  
...  

AbstractNowadays there is an ongoing acute respiratory outbreak caused by the novel highly contagious coronavirus (COVID-19). The diagnostic protocol is based on quantitative reverse-transcription polymerase chain reaction (RT-PCR) and chests CT scan, with uncertain accuracy. This meta-analysis study determines the diagnostic value of an initial chest CT scan in patients with COVID-19 infection in comparison with RT-PCR. Three main databases; PubMed (MEDLINE), Scopus, and EMBASE were systematically searched for all published literature from January 1st, 2019, to the 21st May 2020 with the keywords "COVID19 virus", "2019 novel coronavirus", "Wuhan coronavirus", "2019-nCoV", "X-Ray Computed Tomography", "Polymerase Chain Reaction", "Reverse Transcriptase PCR", and "PCR Reverse Transcriptase". All relevant case-series, cross-sectional, and cohort studies were selected. Data extraction and analysis were performed using STATA v.14.0SE (College Station, TX, USA) and RevMan 5. Among 1022 articles, 60 studies were eligible for totalizing 5744 patients. The overall sensitivity, specificity, positive predictive value, and negative predictive value of chest CT scan compared to RT-PCR were 87% (95% CI 85–90%), 46% (95% CI 29–63%), 69% (95% CI 56–72%), and 89% (95% CI 82–96%), respectively. It is important to rely on the repeated RT-PCR three times to give 99% accuracy, especially in negative samples. Regarding the overall diagnostic sensitivity of 87% for chest CT, the RT-PCR testing is essential and should be repeated to escape misdiagnosis.


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