scholarly journals Comparison of 3 Nucleic Acid Amplification Tests and a Rapid Antigen Test with Culture for the Detection of Group A Streptococci from Throat Swabs

2019 ◽  
Vol 4 (2) ◽  
pp. 164-169 ◽  
Author(s):  
Kyle G Parker ◽  
Sumanth Gandra ◽  
Scott Matushek ◽  
Kathleen G Beavis ◽  
Vera Tesic ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Predictive Value ◽  
Bacterial Culture ◽  
Group A Streptococcus ◽  
Point Of Care ◽  
High Sensitivity ◽  
Ease Of Use ◽  
Nucleic Acid Amplification ◽  
Gold Standard Method ◽  
Group A

Abstract Background Recently, the US Food and Drug Administration cleared 3 nucleic acid amplification test (NAAT) assays for detection of Streptococcus pyogenes [group A Streptococcus (GAS)] in pharyngeal specimens. However, there are limited studies evaluating the performance of these NAAT assays. Methods We compared the results of 3 NAATs (cobas Liat, Luminex Aries, and Cepheid Xpert Xpress) and a rapid antigen assay (Quidel QuickVue in-line strep A) with the accepted gold standard method, bacterial culture. Results Sixty-eight throat swab specimens collected between August and October 2017 were tested. Compared to bacterial culture, the sensitivities, specificities, positive predictive value, and negative predictive value for detecting GAS were as follows: cobas Liat: 100%, 97.4%, 96.7%, and 100%; Cepheid Xpert: 100%, 97.4%, 96.7%, and 100%; Luminex Aries: 95.2%, 100%, 100%, and 95.5%. The Quidel QuickVue in-line strep A assay showed poor sensitivity, detecting only 5.2% of culture-positive specimens. Conclusion The 3 NAATs have high sensitivity when compared with bacterial culture for detection of GAS. With rapid turnaround time and ease of use, these tests can be considered as reliable point-of-care tests for the diagnosis of GAS, replacing the need for back-up culture.

scholarly journals 2158. Cost-Effectiveness and Budget Impact of a Point-of-Care Nucleic Acid Amplification Test for Diagnosis of Group A Streptococcal Pharyngitis in the United States

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S732-S732
Author(s):  
James Karichu ◽  
Mindy Cheng ◽  
Joanna Sickler ◽  
Julie Munakata ◽  
S Pinar Bilir ◽  
...  
Keyword(s):  
United States ◽  
Cost Effectiveness ◽  
Nucleic Acid ◽  
Budget Impact ◽  
Point Of Care ◽  
Cost Savings ◽  
The United States ◽  
Nucleic Acid Amplification ◽  
Sensitivity Analyses ◽  
Group A

Abstract Background Group A streptococcal (GAS) pharyngitis is common in the United States (US). Each year, approximately 12 million people seek medical care for pharyngitis, accounting for ~2% of ambulatory care visits. The gold standard method for diagnosing GAS is culture. However, because culture is time intensive, rapid antigen detection tests (RADTs), with or without culture confirmation, are commonly used. Although RADTs provide results quickly, test sensitivity has been shown to be sub-optimal, which can lead to inappropriate treatment decisions. Recently, highly sensitive point-of-care nucleic acid amplification tests (POC NAAT), such as the cobas® Liat® System, have emerged. The objective of this study was to evaluate the cost-effectiveness (CE) and budget impact (BI) of adopting POC NAAT compared with RADT+culture confirmation to diagnose GAS pharyngitis from the US third-party payer perspective. Methods A decision-tree economic model was developed in Microsoft Excel to quantify costs and clinical outcomes associated with POC NAAT and RADT+culture over a one-year period. All model inputs were derived from published literature and public databases. Model outputs included costs and clinical effects measured as quality-adjusted life days (QALDs) lost. One-way and probabilistic sensitivity analyses were performed to assess the impact of uncertainty on results. Results CE analysis showed that POC NAAT would cost $44 per patient compared with $78 with RADT+ culture. POC NAAT was associated with fewer QALDs lost relative to RADT+ culture. Therefore, POC NAAT may be considered the “dominant” strategy (i.e., lower costs and higher effectiveness). Findings were robust in sensitivity analyses. BI analysis showed that adopting POC NAAT for diagnosis of GAS could yield cost-savings of 0.3% vs. current budget over 3 years. This is due to savings associated with testing, GAS-related complications, antibiotic treatment and treatment-associated complication costs. Conclusion Results suggest that adopting POC NAAT to diagnose GAS would be considered cost-effective and yield cost-savings for US payers relative to RADT+culture. Access to POC NAAT would be important to optimize appropriate GAS diagnosis and treatment decisions. Disclosures All authors: No reported disclosures.

scholarly journals Detection of Group A Streptococcus from Pharyngeal Swab Samples by Bacterial Culture Is Challenged by a Novel mariPOC Point-of-Care Test

2015 ◽  
Vol 53 (7) ◽  
pp. 2079-2083 ◽  
Author(s):  
Jukka Vakkila ◽  
Janne O. Koskinen ◽  
Annika Brandt ◽  
Anna Muotiala ◽  
Viivi Liukko ◽  
...  
Keyword(s):  
Bacterial Culture ◽  
Group A Streptococcus ◽  
Point Of Care ◽  
Clinical Importance ◽  
Test System ◽  
Lower Sensitivity ◽  
Patients Âgés ◽  
Point Of Care Test ◽  
Group A ◽  
Tract Infections

mariPOC is a novel point-of-care test system for rapid detection of respiratory tract infections. We compared the performance of the mariPOC test to that of bacterial culture for detecting group A streptococcus (GAS) in 219 pharyngitis patients (ages 1–64 years) and 109 healthy asymptomatic controls (ages 19–69 years). In addition, 42 patient samples were analyzed by quantitative PCR (qPCR). Of the 219 pharyngeal patient samples, 32 were positive in a GAS bacterial culture (prevalence 15%) and 65 (30%) in the mariPOC test. The amount of GAS in samples reported positive by the mariPOC test and negative by culture was, on average, 10-fold less than that of those positive in both methods. This indicated that the negative results in bacterial cultures were due to lower sensitivity. The qPCR results were positive and in line with the mariPOC results in 43% of the discordant samples studied. Two GAS culture-positive samples were negative by the mariPOC test. The prevalences of GAS in the control subjects were 2% and 6% by culture and mariPOC results, respectively. We conclude that the mariPOC antigen detection test is more sensitive than the conventional bacterial culture for the detection of GAS among symptomatic pharyngitis patients. The higher prevalence of GAS by the mariPOC test among symptomatic patients was probably not due to carriership, since among the control patients, the difference in the prevalence of GAS by the mariPOC test and culture was not nearly as high, 15% versus 4%, respectively. Clinical trials are needed to show the clinical importance of our findings.

Amplification-Free DNA Detection Using a Microtip-Sensor Decorated With LNA Probes for Rapid TB Screening

2011 ◽  
Author(s):  
Shinnosuke Inoue ◽  
Woon-Hong Yeo ◽  
Jong-Hoon Kim ◽  
Jae-Hyun Chung ◽  
Kyong-Hoon Lee ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Staphylococcus Epidermidis ◽  
Genomic Dna ◽  
Bacterial Culture ◽  
Low Cost ◽  
Surrogate Marker ◽  
High Sensitivity ◽  
Diagnostic Methods ◽  
Nucleic Acid Amplification ◽  
Highly Sensitive

Tuberculosis (TB) is an epidemic affecting one-third of the world’s population, mostly in developing and low-resource settings. People having active pulmonary TB are considered highly infectious; therefore, it is critical to identify and treat these patients rapidly before spreading to others. However, the most reliable TB diagnostic methods of bacterial culture or nucleic acid amplification are time-consuming and expensive. The challenge of TB diagnosis lies in highly sensitive and specific screening with low cost. Here, we present an LNA-modified microtip-sensor, which is capable of selectively detecting low-abundance DNA from bacteria. When genomic DNA of Bacillus Calmette-Gue´rin (BCG, a surrogate marker of Mycobacterium bovis), and genomic DNA of Staphylococcus epidermidis (S. epi) are used, the microtip-sensor yields the detection limit of 1,000 copies/mL within 20 minutes. The high sensitivity and specificity approaching nucleic acid amplification methods can potentially overcome the current challenges for rapid TB screening.

scholarly journals A comparative study of isothermal nucleic acid amplification methods for SARS-CoV-2 detection at point of care

2020 ◽  
Author(s):  
Diem Hong Tran ◽  
Hoang Quoc Cuong ◽  
Hau Thi Tran ◽  
Uyen Phuong Le ◽  
Hoang Dang Khoa Do ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Limit Of Detection ◽  
Direct Detection ◽  
Point Of Care ◽  
Nucleic Acid Amplification ◽  
Gold Standard Method ◽  
Synthetic Dna ◽  
Isothermal Nucleic Acid Amplification ◽  
Freeze Dried ◽  
Test Kit

ABSTRACTThe COVID-19, caused by the novel coronavirus SARS-CoV-2, has broken out of control all over the globe and put the majority of the world under lockdown. There have been no specific antiviral medications for SARS-CoV-2 while vaccines are still under development. Thus, rapid diagnosis and necessary public health measures are currently key parts to contain the pandemic. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) is the gold standard method for SARS-CoV-2 detection. However, this method is not suitable for point-of-care (POC) diagnosis because of the timeconsuming procedure, the requirements of biosafety conditions and expensive equipment. In this study, the colorimetric isothermal nucleic acid amplification tests (iNAATs) for SARS-CoV-2 based on loop-mediated isothermal amplification (LAMP), cross-priming amplification (CPA), and polymerase spiral reaction (PSR) were developed and compared. The three methods exhibited similar performance with the limit of detection (LOD) as low as just 1 copy per reaction when evaluated on the synthetic DNA fragments. The results can be read with naked eyes within 30 minutes without crossreactivity to closely related coronaviruses. When tested with SARS-CoV-2 extracted genomic-RNA, LAMP outperformed both CPA and PSR assays. Moreover, the direct detection of SARS-CoV-2 in simulated patient samples (oropharyngeal and nasopharyngeal swabs) by colorimetric iNAATs was also successful. Further preparation of the lyophilized reagents for LAMP reactions revealed that the freeze-dried, ready-to-use kit maintained the sensitivity and LOD value of the liquid assays. These results strongly indicate that the colorimetric lyophilized LAMP test kit developed herein is highly suitable for detecting SARS-CoV-2 at POC.

scholarly journals Performance of Cartridge Based Nucleic Acid Amplification Test for the Diagnosis of Smear Negative Suspected Tuberculosis - A Study from a Teaching Hospital in Thrissur, Kerala, India

2021 ◽  
Vol 10 (16) ◽  
pp. 1114-1118
Author(s):  
Anupama Sethumadhavan ◽  
Kavitha Paul Konikkara ◽  
Davis Paul
Keyword(s):  
Nucleic Acid ◽  
Predictive Value ◽  
Gold Standard ◽  
Sputum Sample ◽  
False Negative ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
World Health ◽  
Gold Standard Method ◽  
Smear Negative

BACKGROUND In India, everyday more than 6000 people develop tuberculosis (TB) and more than 600 people die of TB (2 death every 5 minutes).1 World Health Organization (WHO) has recently endorsed cartridge based nucleic acid amplification test (CBNAAT) which has the potential to lead a revolution in the diagnosis of tuberculosis. This study intends to assess the performance of CBNAAT for the diagnosis of suspected smear negative pulmonary and extra pulmonary tuberculosis. METHODS The cross-sectional study was carried out in Department of Microbiology, Government Medical College, Thrissur, Kerala, India. CBNAAT was done in district tuberculosis center, Thrissur. The study was done from December 2016 to December 2017. Samples were sent for microscopy, culture and CBNAAT. RESULTS A total of 250 patients were evaluated. Majority of the specimens collected were sputum (61.2 %) followed by bronchial wash (17.6 %). Culture was positive in 48 specimens. CBNAAT was positive in 58 specimens. Both culture and CBNAAT were positive in 47 patients. CBNAAT was negative in 1 specimen but positive in culture test. CBNAAT detected an additional 10 samples. Taking culture as gold standard, culture positives were taken as true positives and culture negatives were taken as true negatives. Accordingly, true positive was 48, true negative was 202, false positive was 10 and false negative was 1. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were respectively 97.95 %, 95.2 %, 82.75 % and 99.5 %. CBNAAT missed out a sputum sample which was culture positive. CONCLUSIONS We found CBNAAT to be an important diagnostic modality especially in smear negative patients for early diagnosis and treatment of TB. Culture of mycobacteria is considered as a gold standard method, but it takes weeks to obtain a positive result and simultaneous detection of rifampicin resistance is not possible with this method. KEY WORDS Tuberculosis, Smear Negative TB, ZN Stain, AFB, Petroff’s Method, CBNAAT, RNTCP, Culture

scholarly journals Point-Counterpoint: A Nucleic Acid Amplification Test for Streptococcus pyogenes Should Replace Antigen Detection and Culture for Detection of Bacterial Pharyngitis

2016 ◽  
Vol 54 (10) ◽  
pp. 2413-2419 ◽  
Author(s):  
Bobbi S. Pritt ◽  
Robin Patel ◽  
Thomas J. Kirn ◽  
Richard B. Thomson
Keyword(s):  
Nucleic Acid ◽  
Respiratory Infections ◽  
Antigen Detection ◽  
Ease Of Use ◽  
Nucleic Acid Amplification ◽  
Clinical Settings ◽  
Great Success ◽  
Content Type ◽  
Group A ◽  
Testing Algorithms

Nucleic acid amplification tests (NAATs) have frequently been the standard diagnostic approach when specific infectious agents are sought in a clinic specimen. They can be applied for specific agents such asS. pyogenes, or commercial multiplex NAATs for detection of a variety of pathogens in gastrointestinal, bloodstream, and respiratory infections may be used. NAATs are both rapid and sensitive. For many years,S. pyogenestesting algorithms used a rapid and specific group A streptococcal antigen test to screen throat specimens, followed, in some clinical settings, by a throat culture forS. pyogenesto increase the sensitivity of its detection. NowS. pyogenesNAATs are being used with increasing frequency. Given their accuracy, rapidity, and ease of use, should they replace antigen detection and culture for the detection of bacterial pharyngitis? Bobbi Pritt and Robin Patel of the Mayo Clinic, whereS. pyogenesNAATs have been used for well over a decade with great success, will explain the advantages of this approach, while Richard (Tom) Thomson and Tom Kirn of the NorthShore University HealthSystem will discuss their concerns about this approach to diagnosing bacterial pharyngitis.

scholarly journals Multicenter Clinical Evaluation of the Novel Alere i Strep A Isothermal Nucleic Acid Amplification Test

2015 ◽  
Vol 53 (7) ◽  
pp. 2258-2261 ◽  
Author(s):  
Daniel M. Cohen ◽  
Michael E. Russo ◽  
Preeti Jaggi ◽  
Jennifer Kline ◽  
William Gluckman ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Clinical Laboratory ◽  
Point Of Care ◽  
Prospective Trial ◽  
Nucleic Acid Amplification Test ◽  
Nucleic Acid Amplification ◽  
Isothermal Nucleic Acid Amplification ◽  
Negative Results ◽  
Group A ◽  
Low Sensitivity

Rapid detection of group A beta-hemolytic streptococcus (GAS) is used routinely to help diagnose and treat pharyngitis. However, available rapid antigen detection tests for GAS have relatively low sensitivity, and backup testing is recommended in children. Newer assays are more sensitive yet require excessive time for practical point-of-care use as well as laboratory personnel. The Alere i strep A test is an isothermal nucleic acid amplification test designed to offer highly sensitive results at the point of care within 8 min when performed by nonlaboratory personnel. The performance of the Alere i strep A test was evaluated in a multicenter prospective trial in a Clinical Laboratory Improvement Amendments (CLIA)-waived setting in comparison to bacterial culture in 481 children and adults. Compared to culture, the Aleri i strep A test had 96.0% sensitivity and 94.6% specificity. Discrepant results were adjudicated by PCR and found the Alere i strep A test to have 98.7% sensitivity and 98.5% specificity. Overall, the Alere i strep A test could provide a one-step, rapid, point-of-care testing method for GAS pharyngitis and obviate backup testing on negative results.

scholarly journals 444. Better Efficiency, Same Accuracy: Point-of-Care PCR for the Detection of Group A streptococcus in Noninvasive Skin Infections

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S219-S219
Author(s):  
Patrick D Galdun ◽  
Ryan M Close ◽  
Catherine Sutcliffe ◽  
Dennie R Parker ◽  
Angelina Reid ◽  
...  
Keyword(s):  
Predictive Value ◽  
Group A Streptococcus ◽  
Point Of Care ◽  
Antibiotic Use ◽  
The United States ◽  
Diagnostic Techniques ◽  
Antibiotic Prescribing ◽  
Roche Molecular Diagnostics ◽  
Group A ◽  
Culture Positive

Abstract Background Group A streptococcus (GAS) is a common cause of skin and soft-tissue infections (SSTIs). Current diagnostic techniques are culture-based and time intensive, requiring the prescription of empiric antibiotics before results are available. New detection tools are needed to hasten the diagnosis and appropriate treatment of SSTIs. The Cobas® Liat® System is a point of care (POC), real-time PCR system developed by Roche Molecular Diagnostics and is used in the United States and Europe to detect GAS from throat swabs within 15 minutes. We evaluated the feasibility and performance characteristics of POC for the detection of GAS in non-severe SSTIs. Methods Wound swabs collected from patients presenting to the Whiteriver Indian Health Service Hospital with non-severe SSTIs requiring only outpatient treatment were eligible for inclusion. Two swabs were collected: one swab was cultured on sheep’s blood agar, and the other swab was tested using POC. Compared with culture, we determined the sensitivity (SN), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) for POC to detect GAS in wound samples. We performed chart reviews 30-days from eligibility to assess the potential impact of POC systems on antibiotic use and healthcare utilization for SSTIs. Results To date, we have tested 100 (25%) of our target 400 samples (enrollment will be complete in August 2019). Of the 100 samples, 50 (50%) tested positive for GAS by POC, all of which were culture positive for GAS, 49 tested negative by POC (2 after a first invalid result), all of which tested culture negative for GAS (table), and 1 had an invalid POC result even after repeat testing (culture positive for MRSA only) and was excluded from further analysis. Among samples with a valid POC result, POC SN was 100%, SP was 100%, PPV was 100%, and NPV was 100%. The most common mono-infections were MRSA (22%), GAS (18%), and CoNS (6%). Among GAS cases, MSSA (32%) and MRSA (18%) co-infection was common. Conclusion POC PCR is highly sensitive and specific for the detection of GAS in non-severe SSTIs. To our knowledge, this is the first prospective study to use this technology for wound samples. POC PCR methods have the potential to accelerate identification of SSTI pathogens and improve antibiotic prescribing. Disclosures All authors: No reported disclosures.

scholarly journals Evaluation of Production Lots of a Rapid Point-of-Care Lateral Flow Serological Test Intended for Identification of IgM and IgG against the N-Terminal Part of the Spike Protein (S1) of SARS-CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1043
Author(s):  
Tove Hoffman ◽  
Linda Kolstad ◽  
Bengt Rönnberg ◽  
Åke Lundkvist
Keyword(s):  
Predictive Value ◽  
Serological Test ◽  
Point Of Care ◽  
External Validation ◽  
High Sensitivity ◽  
Lateral Flow ◽  
Spike Protein ◽  
Individual Level ◽  
Lateral Flow Test ◽  
Production Errors

The potential of rapid point-of-care (POC) tests has been subject of doubt due to an eventual risk of production errors. The aim was therefore to evaluate the two separate production lots of a commercial POC lateral flow test, intended for the detection of IgM and IgG against the SARS-CoV-2 spike protein (S1). Control samples consisted of serum from individuals with confirmed SARS-CoV-2 infection and pre-COVID-19 negative sera gathered from a biobank. The presence of anti-S1 IgM/IgG in the sera was verified by an in-house Luminex-based serological assay (COVID-19 SIA). One hundred samples were verified as positive for anti-S1 IgG and 74 for anti-S1 IgM. Two hundred samples were verified as negative for anti-S1 IgM/IgG. For the two lots of the POC-test, the sensitivities were 93.2% and 87.8% for IgM and 93.0% and 100% for IgG. The specificities were 100% for IgM and 99.5% for IgG. The positive predictive value was 100% for IgM and 98.9% and 99.0% for IgG. The negative predictive value was 97.6% and 95.7% for IgM, and 96.6% and 100% for IgG. The evaluated POC-test is suitable to assess anti-SARS-CoV-2 S1 IgM and IgG, as a measure of previous virus exposure on an individual level. The external validation of separate lots of rapid POC-tests is encouraged to ensure high sensitivity before market introduction.

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