Laboratory-based evaluation of a simplified point-of-care test intended to support treatment decisions in non-severe bovine clinical mastitis

Abstract To limit the use of antimicrobials in dairy cattle, farmers are increasingly encouraged to adopt targeted treatment decisions based on knowledge of the pathogens causing clinical mastitis (CM), whereby treatment of non-severe CM is generally recommended for gram-positive mastitis but not for gram-negative or culture-negative mastitis. The objectives of this study were to conduct a laboratory-based evaluation of the performance of a simplified slide test as a tool to differentiate gram-positive CM from other cases of CM, and to compare its performance against a commercially available on-farm test that is commonly used in our area (VétoRapid). Test outcomes after 24–48 h incubation were compared to results from bacteriological culture and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS). Milk samples (n = 156) were obtained from cases of severe and non-severe CM on seven farms and collected by farm personnel. After removal of small numbers of contaminated samples and organisms with unknown species identity, the simplified slide test showed high sensitivity and accuracy (>80%), similar to the comparator test. For most outcomes of interest (culture positive, Escherichia coli, or gram-positive growth), the specificity of the slide test was higher than the specificity of the comparator test. When considering non-severe cases of CM only, and interpreting detection of gram-positive organisms as indicative of the need for antimicrobial treatment, the simplified test had higher specificity (77.4% v. 60.4%) and higher positive predictive value (79.7% v. 70.0%) than the comparator test and similar sensitivity (83.9% v. 87.5%). The proportion of sampled CM cases, contaminated samples and gram-positive mastitis cases – which affects the positive and negative predictive value, the economic value of diagnostic testing and its potential to reduce antimicrobial use – differed between farms. The simplicity and accuracy of the slide test could make it an attractive tool for farmers to target antimicrobial treatment of non-severe clinical mastitis.

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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 ◽

10.3390/v13061043 ◽

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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Immobilized Enzymes in Biosensor Applications

Materials ◽

10.3390/ma12010121 ◽

2019 ◽

Vol 12 (1) ◽

pp. 121 ◽

Cited By ~ 63

Author(s):

Hoang Hiep Nguyen ◽

Sun Hyeok Lee ◽

Ui Jin Lee ◽

Cesar D. Fermin ◽

Moonil Kim

Keyword(s):

Point Of Care ◽

Measurement Techniques ◽

Diagnostic Testing ◽

High Sensitivity ◽

Immobilized Enzymes ◽

Clinical Analysis ◽

Safety Control ◽

Wide Range ◽

Piezoelectric Measurement ◽

Innovative Techniques

Enzyme-based biosensing devices have been extensively developed over the last few decades, and have proven to be innovative techniques in the qualitative and quantitative analysis of a variety of target substrates over a wide range of applications. Distinct advantages that enzyme-based biosensors provide, such as high sensitivity and specificity, portability, cost-effectiveness, and the possibilities for miniaturization and point-of-care diagnostic testing make them more and more attractive for research focused on clinical analysis, food safety control, or disease monitoring purposes. Therefore, this review article investigates the operating principle of enzymatic biosensors utilizing electrochemical, optical, thermistor, and piezoelectric measurement techniques and their applications in the literature, as well as approaches in improving the use of enzymes for biosensors.

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TUBERCULOUS PERICARDITIS AND PLEURITIS;

The Professional Medical Journal ◽

10.29309/tpmj/2017.24.05.1379 ◽

2017 ◽

Vol 24 (05) ◽

pp. 656-664

Author(s):

Hamid Mahmood ◽

Talmeez Zaib ◽

Zafar Hayat Maken ◽

Ammara Waqar ◽

Yasir Hassan ◽

...

Keyword(s):

Negative Predictive Value ◽

Predictive Value ◽

Point Of Care ◽

High Sensitivity ◽

Smear Microscopy ◽

Diagnostic Validity ◽

Standard Material ◽

Point Of Care Test ◽

Resource Limited ◽

Attractive Point

Background: Diagnosis of Tubercles Pericarditis and Pleuritis remains thegreatest challenge for clinicians. WHO has recommended GeneXpert MTB/RIF assay as ascreening test for substitution of conventional methods for the initial diagnosis and prognosisof the extra pulmonary and pulmonary tuberculosis in developing countries. Objectives: Tofind out the diagnostic validity of GeneXpert assay for detection of Myco-bacterium tuberculosisin the pericardial and pleural effusions samples, keeping MTB culture as “Gold Standard”.Material and Methods: Total number of 286 samples of effusions (pericardial 128, pleural 158)were received, and processed for Zn smear microscopy, LJ culture, GeneXpert MTB/RIF assayaccording standard protocols. Efficacy for the detection of MTB was evaluated comparatively.Results: Out of 286effusions samples AFB was detected by Zn smear in 11 (3.8%) samples whileGeneXpert detected MTB in 43 (15.0%) and LJ culture 51 (17.8%). Zn smear showed sensitivity18.2%, specificity, 98.1%, Positive predictive value 81.8%, Negative predictive value 85.4 %, incomparison GeneXpert showed high sensitivity 84.3%, specificity 100%, with Positive predictivevalue 100%, and Negative predictive value 96.7%. Conclusion: GeneXpert assay is innovativetool in resource limited settings for prompt detection of MTB along with drug résistance. It isdefinitely an attractive point of care test, with High sensitivity and specificity along with turnouttime of two hours which facilitates timely diagnoses and appropriate management of tuberclePleuritis and Pericarditis.

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Comparison of Point-of-Care Ultrasonography and Radiography in the Diagnosis of Long-Bone Fractures

Medicina ◽

10.3390/medicina55070355 ◽

2019 ◽

Vol 55 (7) ◽

pp. 355 ◽

Cited By ~ 5

Author(s):

Avci ◽

Kozaci ◽

Tulubas ◽

Caliskan ◽

Yuksel ◽

...

Keyword(s):

Predictive Value ◽

Bone Fractures ◽

Point Of Care ◽

High Sensitivity ◽

Long Bone ◽

Imaging Method ◽

Fracture Characteristics ◽

Point Of Care Ultrasonography ◽

Sensitivity Specificity

Background and objectives: In this study, the accuracy of point-of-care ultrasonography (POCUS) was compared to radiography (XR) in the diagnosis of fractures, the determination of characteristics of the fractures, and treatment selection of fractures in patients admitted to the emergency department (ED) due to trauma and suspected long bone (LB) fractures. Materials and Methods: The patients were included in the study, who were admitted to ED due to trauma, and had physical examination findings suggesting the presence of fractures in LB (humerus, radius, ulna, femur, tibia, and fibula). The patients were evaluated by two emergency physicians (EP) in ED. The first EP examined LBs with POCUS and the second EP examined them with XR. LBs were evaluated on the anterior, posterior, medial, and lateral surfaces and from the proximal joint to the distal one (shoulder, elbow, wrist, hip, knee, and ankle joint) in both longitudinal and transverse axes with POCUS. Results: A total of 205 patients with suspected LB fractures were included in the study. LB fractures were determined in 99 patients with XR and in 105 patients with POCUS. The sensitivity, specificity, positive predictive value, negative predictive value of POCUS in determining the fractures were 99%, 93%, 93%, and 99%, respectively, compared to XR. Compared to XR, POCUS was able to determine 100% of fissure type fractures (kappa (κ) value: 0.765), 83% of linear fractures (κ: 0.848), 92% of fragmented fractures(κ: 0.756), 67% of spiral fractures (κ:0.798), 75% of avulsion type fractures (κ: 0.855), and 100% of full separation type fractures (κ: 0.855).Conclusions: This study has demonstrated that POCUS has a high sensitivity in diagnosing LB fractures. POCUS has a high sensitivity in identifying fracture characteristics. POCUS can be used as an alternative imaging method to XR in the diagnosis of LB fractures and in the determination of fracture characteristics.

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Bioengineered Polymer/Composites as Advanced Biological Detection of Sorbitol: An Application in Healthcare Sector

Current Topics in Medicinal Chemistry ◽

10.2174/1568026620666200306131416 ◽

2020 ◽

Vol 20 (11) ◽

pp. 963-981

Author(s):

Ruma Rani ◽

Geeta Singh ◽

Kanisht Batra ◽

Prasad Minakshi

Keyword(s):

Point Of Care ◽

Diagnostic Testing ◽

High Sensitivity ◽

Advanced Materials ◽

Healthcare Sector ◽

Biological Detection ◽

Detection Techniques ◽

Sensitivity And Selectivity ◽

Healthcare Application ◽

Higher Sensitivity

Bioengineered polymers and nanomaterials have emerged as promising and advanced materials for the fabrication and development of novel biosensors. Nanotechnology-enabled biosensor methods have high sensitivity, selectivity and more rapid detection of an analyte. Biosensor based methods are more rapid and simple with higher sensitivity and selectivity and can be developed for point-of-care diagnostic testing. Development of a simple, sensitive and rapid method for sorbitol detection is of considerable significance to efficient monitoring of diabetes-associated disorders like cataract, neuropathy, and nephropathy at initial stages. This issue encourages us to write a review that highlights recent advancements in the field of sorbitol detection as no such reports have been published till the date. The first section of this review will be dedicated to the conventional approaches or methods that had been playing a role in detection. The second part focused on the emerging field i.e. biosensors with optical, electrochemical, piezoelectric, etc. approaches for sorbitol detection and the importance of its detection in healthcare application. It is expected that this review will be very helpful for readers to know the different conventional and recent detection techniques for sorbitol at a glance.

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Evaluation of the Alere Pima™ for CD4+ T lymphocytes counts in HIV-positive outpatients in Southern Brazil

International Journal of STD & AIDS ◽

10.1177/0956462414526862 ◽

2014 ◽

Vol 25 (13) ◽

pp. 956-959 ◽

Cited By ~ 9

Author(s):

L Rathunde ◽

GMB Kussen ◽

MP Beltrame ◽

LM Dalla Costa ◽

SM Raboni

Keyword(s):

Flow Cytometry ◽

T Lymphocytes ◽

T Lymphocyte ◽

Predictive Value ◽

Opportunistic Infections ◽

Point Of Care ◽

High Sensitivity ◽

Hiv Positive ◽

Point Of Care Test ◽

Patients At Risk

CD4 + lymphocyte counts are routinely ordered during the early phases of antiretroviral therapy and for prophylaxis of opportunistic infections in HIV-positive patients. Flow cytometry is the standard methodology for CD4 counts in Brazilian reference laboratories. However, these laboratories are located in large cities, frequently distant from patients, thus limiting patient access and delaying results. We compared a point-of-care test with flow cytometry determination of CD4+ T lymphocyte counts in HIV patients. We analysed 107 consecutive samples by both methods. Overall, the point-of-care test performed well, with excellent agreement between it and the standard method. Test results were concordant for patients with CD4+ T lymphocyte values above and below 200 cells/mm 3. The performance characteristics obtained were sensitivity 94% (95% CI 89.5–98.5%), specificity 93% (95% CI 88.2–97.8%), positive predictive value 86% (95% CI 79.4–92.6%), and negative predictive value 97% (95% CI 94–100%). The high sensitivity and specificity of the point-of-care test methodology suggest its utility as an alternative method for rapid measurement of CD4+ T lymphocytes in patients with limited access to reference laboratories, enabling prompt therapeutic intervention for patients at risk of progression to AIDS.

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Analytical performance of the point-of-care BIOSYNEX COVID-19 Ag BSS for the detection of SARS‐CoV‐2 nucleocapsid protein in nasopharyngeal swabs: a prospective field evaluation during the COVID-19 third wave in France

Infection ◽

10.1007/s15010-021-01723-5 ◽

2021 ◽

Author(s):

Frédéric Fitoussi ◽

Serge Tonen-Wolyec ◽

Natalio Awaida ◽

Raphaël Dupont ◽

Laurent Bélec

Keyword(s):

Predictive Value ◽

Nucleocapsid Protein ◽

Point Of Care ◽

High Sensitivity ◽

Field Evaluation ◽

Analytical Performance ◽

N Gene ◽

Youden Index ◽

Rt Pcr ◽

Viral Excretion

Abstract Background The accuracy and reliability of rapid diagnostic tests are critical for monitoring and diagnosing SARS-CoV-2 infection in the general population. This study aimed to evaluate the analytical performance of the BIOSYNEX COVID-19 Ag BSS (Biosynex Swiss SA, Fribourg, Switzerland) antigen rapid diagnostic test (BIOSYNEX Ag-RDT), which targets the SARS-CoV-2 N-nucleocapsid protein for the diagnosis of COVID-19. The Ag-RDT was compared with a real-time RT-PCR (rtRT-PCR) as gold standard for performance measurement. Methods Two nasopharyngeal flocked swabs were prospectively collected simultaneously in March and April 2021 from 967 individuals aged ≥ 18 years tested for SARS-CoV-2 in two private laboratories, Paris, France. Results Overall, the Ag-RDT demonstrated high sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 81.8%, 99.6%, 96.6%, and 97.5%, respectively. The agreement (97.0%), reliability assessed using Cohen’s κ-coefficient (0.87), and accuracy evaluated using Youden index (J) (81.6%) in detecting SARS-CoV-2 were high. The analytical performance of the Ag-RDT remained high when there was significant viral shedding (i.e., N gene Ct values ≤ 33 on reference RT-PCR). The sensitivity was only 55.2% in case of low or very low viral excretion (Ct > 33). Conclusions The BIOSYNEX Ag-RDT is a promising, potentially simple diagnostic tool, especially in symptomatic COVID-19 patients with substantial viral excretion in the nasopharynx.

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Diagnostic Evaluation of a High-Sensitivity Troponin I Point-of-Care Assay

Clinical Chemistry ◽

10.1373/clinchem.2019.307405 ◽

2019 ◽

Vol 65 (12) ◽

pp. 1592-1601 ◽

Cited By ~ 9

Author(s):

Nils A Sörensen ◽

Johannes T Neumann ◽

Francisco Ojeda ◽

Evangelos Giannitsis ◽

Eberhard Spanuth ◽

...

Keyword(s):

Myocardial Infarction ◽

Predictive Value ◽

Diagnostic Performance ◽

Troponin I ◽

Point Of Care ◽

Diagnostic Algorithm ◽

High Sensitivity ◽

Data Set ◽

High Sensitivity Troponin ◽

Point Of Care Assay

Abstract BACKGROUND Increasing numbers of patients are presenting worldwide to emergency departments with suspected myocardial infarction. The use of point-of-care troponin assays might enable faster decision-making in this high-risk population and reduce the burden on emergency facilities. Here, we evaluate the diagnostic performance of a point-of-care high-sensitivity troponin I assay. METHODS We conducted a prospective cohort study including patients presenting to the emergency department with suspected myocardial infarction from July 2013 to July 2016. A diagnostic algorithm for a high-sensitivity troponin I point-of-care assay was developed in a derivation data set with 669 patients and validated in an additional 610 patients. RESULTS The derived 0/1 h algorithm for the point-of-care assay consisted of an admission troponin I <4 ng/L and a δ from 0 h to 1 h <3 ng/L for rule out and an admission troponin I ≥90 ng/L or a δ from 0 h to 1 h ≥20 ng/L for rule in of non-ST-elevation myocardial infarction. Application to the validation cohort showed a negative predictive value of 99.7% (95% CI, 98.1%–100.0%) and 48.0% of patients ruled out, whereas 14.6% were ruled in with a positive predictive value of 86.5% (95% CI, 77.6%–92.8%). The diagnostic performance of the point-of-care high-sensitivity assay was highly comparable to guideline-recommended use of a laboratory-based high-sensitivity troponin assay. CONCLUSIONS The clinical application of a 0/1 h diagnostic algorithm based on a high-sensitivity troponin I point-of-care assay is safe, and diagnostic performance is comparable to a laboratory-based high-sensitivity troponin I assay.

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

The Journal of Applied Laboratory Medicine ◽

10.1373/jalm.2018.028696 ◽

2019 ◽

Vol 4 (2) ◽

pp. 164-169 ◽

Cited By ~ 4

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.

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Analytical Performances of the Point-of-Care BIOSYNEX COVID-19 Ag BSS for the Detection of SARS‐CoV‐2 Nucleocapsid Protein in Nasopharyngeal Swabs: A Prospective Field Evaluation During the COVID-19 Third Wave in France

10.21203/rs.3.rs-519746/v1 ◽

2021 ◽

Author(s):

Fréderic Fitoussi ◽

Serge Tonen-Wolyec ◽

Natalio Awaida ◽

Raphael Dupont ◽

Laurent Belec

Keyword(s):

Nucleocapsid Protein ◽

Point Of Care ◽

Diagnostic Testing ◽

High Sensitivity ◽

High Specificity ◽

Field Evaluation ◽

N Gene ◽

Third Wave ◽

Perfect Agreement ◽

Viral Excretion

Abstract Background: Evaluating the accuracy and reliability of rapid diagnostic testing kits is crucial for surveillance and diagnosis of SARS-CoV-2 infections in general population. The aim of the study was to assess the analytical performances of the antigen-rapid diagnosis test (Ag-RDT) BIOSYNEX COVID-19 Ag BSS (Biosynex Swiss SA, Freiburg, Switzerland), targeting the SARS-CoV-2 N nucleocapsid protein, for the diagnosis of COVID-19, by reference to real-time RT-PCR (rtRT-PCR).Methods: A total 967 adults living in Paris region were prospectively included during the third wave of the COVID-19 epidemic in France. Paired nasopharyngeal flocked swabs were collected at the same timepoint from persons aged ≥18 years receiving testing for SARS-CoV-2, at two private laboratories.Results: Overall, the Ag-RDT showed high sensitivity, specificity, PPV and NPV of 81.8%, 99.6%, 96.6% and 97.5%, respectively, as well as high or almost perfect agreement (97.0%), reliability assessed by Cohen’s κ coefficient (0.87), and accuracy assessed by Youden’s J index (81.6%) to detect SARS-CoV-2. The analytical performances of the Ag-RDT remained high in the event of significant viral excretion (i.e., N gene Ct values ≤ 33 by reference rtRT-PCR), while the sensitivity of the Ag-RDT dropped to 55.2% with low or very low viral shedding (Ct> 33).Conclusions: The Ag-RDT BIOSYNEX COVID-19 Ag BSS showed high specificity and sufficient sensitivity for the detection of SARS-CoV-2. This test is a promising potential easy diagnostic tool, especially in situations of symptomatic COVID-19 and/or proven contagiousness.

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