Multiplexed, quantitative serological profiling of COVID-19 from blood by a point-of-care test

Highly sensitive, specific, and point-of-care (POC) serological assays are an essential tool to manage coronavirus disease 2019 (COVID-19). Here, we report on a microfluidic POC test that can profile the antibody response against multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens—spike S1 (S1), nucleocapsid (N), and the receptor binding domain (RBD)—simultaneously from 60 μl of blood, plasma, or serum. We assessed the levels of antibodies in plasma samples from 31 individuals (with longitudinal sampling) with severe COVID-19, 41 healthy individuals, and 18 individuals with seasonal coronavirus infections. This POC assay achieved high sensitivity and specificity, tracked seroconversion, and showed good concordance with a live virus microneutralization assay. We can also detect a prognostic biomarker of severity, IP-10 (interferon-γ–induced protein 10), on the same chip. Because our test requires minimal user intervention and is read by a handheld detector, it can be globally deployed to combat COVID-19.

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Multiplexed, quantitative serological profiling of COVID-19 from a drop of blood by a point-of-care test

10.1101/2020.11.05.20226654 ◽

2020 ◽

Author(s):

Jacob T. Heggestad ◽

David S. Kinnamon ◽

Lyra B. Olson ◽

Jason Liu ◽

Garrett Kelly ◽

...

Keyword(s):

Antibody Response ◽

Point Of Care ◽

High Sensitivity ◽

Multiple Time ◽

Live Virus ◽

Point Of Care Test ◽

Highly Sensitive ◽

Good Concordance ◽

Multiple Time Points ◽

User Intervention

AbstractHighly sensitive, specific, and point-of-care (POC) serological assays are an essential tool to manage the COVID-19 pandemic. Here, we report on a microfluidic, multiplexed POC test that can profile the antibody response against multiple SARS-CoV-2 antigens—Spike S1 (S1), Nucleocapsid (N), and the receptor binding domain (RBD)—simultaneously from a 60 µL drop of blood, plasma, or serum. We assessed the levels of anti-SARS-CoV-2 antibodies in plasma samples from 19 individuals (at multiple time points) with COVID-19 that required admission to the intensive care unit and from 10 healthy individuals. This POC assay shows good concordance with a live virus microneutralization assay, achieved high sensitivity (100%) and specificity (100%), and successfully tracked the longitudinal evolution of the antibody response in infected individuals. We also demonstrated that we can detect a chemokine, IP-10, on the same chip, which may provide prognostic insight into patient outcomes. Because our test requires minimal user intervention and is read by a handheld detector, it can be globally deployed in the fight against COVID-19 by democratizing access to laboratory quality tests.

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Novel High Sensitivity Tuberculosis Point-of-Care Test for People Living with HIV

SSRN Electronic Journal ◽

10.2139/ssrn.3254479 ◽

2018 ◽

Cited By ~ 2

Author(s):

Tobias Broger ◽

Bianca Sossen ◽

Elloise du Toit ◽

Andrew D. Kerkhoff ◽

Charlotte Schutz ◽

...

Keyword(s):

Point Of Care ◽

High Sensitivity ◽

People Living With Hiv ◽

Point Of Care Test ◽

Living With Hiv

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Diagnostic tests for detecting Chlamydia trachomatis and Neisseria gonorrhoeae in rectal and pharyngeal specimens

Journal of Clinical Microbiology ◽

10.1128/jcm.00211-21 ◽

2021 ◽

Author(s):

Paul C. Adamson ◽

Jeffrey D. Klausner

Keyword(s):

Chlamydia Trachomatis ◽

Neisseria Gonorrhoeae ◽

Bacterial Infections ◽

Point Of Care ◽

High Sensitivity ◽

Population Level ◽

The United States ◽

Nucleic Acid Amplification ◽

Point Of Care Test ◽

Control And Prevention

Chlamydia trachomatis and Neisseria gonorrhoeae are two of the most often reported bacterial infections in the United States. The rectum and oropharynx are important anatomic sites of infection and can contribute to ongoing transmission. Nucleic acid amplification tests (NAATs) are the mainstays for the detection of C. trachomatis and N. gonorrhoeae infections owing to their high sensitivity and specificity. Several NAATs have been evaluated for testing in rectal and pharyngeal infections. A few assays recently received clearance by the Food and Drug Administration, including one point-of-care test. Those assays can be used for testing in symptomatic individuals, as well as for asymptomatic screening in certain patient populations. Routine screening for C. trachomatis in pharyngeal specimens is not recommended by the Centers for Disease Control and Prevention, though is often performed due to the use of multiplex assays. While expanding the types of settings for screening and using self-collected rectal and pharyngeal specimens can help to increase access and uptake of testing, additional research is needed to determine the potential benefits and costs associated with increased screening for rectal and pharyngeal C. trachomatis and N. gonorrhoeae infections on a population level.

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Diagnostic accuracy of a host response point-of-care test in patients with suspected COVID-19

10.1101/2020.05.27.20114512 ◽

2020 ◽

Author(s):

Tristan W Clark ◽

Nathan J Brendish ◽

Stephen Poole ◽

Vasanth V Naidu ◽

Christopher Mansbridge ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Host Response ◽

Clinical Symptoms ◽

Point Of Care ◽

Patient Flow ◽

High Sensitivity ◽

Likelihood Ratios ◽

Duration Of Symptoms ◽

Point Of Care Test ◽

Hospitalised Patients

AbstractRationaleManagement of the COVID-19 pandemic is hampered by long delays associated with centralised laboratory PCR testing. In hospitals this leads to poor patient flow and nosocomial transmission and rapid, accurate diagnostic tests are urgently required. The FebriDx is a point-of-care test that detects an antiviral host response protein in finger prick blood within 10 minutes, but its accuracy for the detection of COVID-19 is unknown.ObjectivesTo evaluate the diagnostic accuracy of FebriDx in hospitalised patients during the first wave of the pandemicMethodsMeasures of diagnostic accuracy were calculated based on FebriDx results compared to the reference standard of PCR, and stratified by duration of symptoms. A multivariable predictive model was developed and underwent internal validation.ResultsFebriDx was performed on 251 patients and gave a valid result in 248. 118 of 248 (48%) were PCR positive for COVID-19. Sensitivity of FebriDx for the identification of COVID-19 was 93% (110/118; 95% CI 87 to 97%) and specificity was 86% (112/130; 95%CI 79 to 92%). Positive and negative likelihood ratios were 6.73 (95%CI 4.37 to 10.37) and 0.08 (95%CI 0.04 to 0.15) respectively. In the multivariate model diagnosis of COVID-19 was not significantly influenced by clinical symptoms and signs, and FebriDx accuracy was not improved by restricting testing to those with duration of symptoms of less than seven days.ConclusionsDuring the first wave of the pandemic, FebriDx had high sensitivity for the identification of COVID-19 in hospitalised adults and could be deployed as a front door triage tool.Trial registrationISRCTN14966673

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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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Associations of β-hydroxybutyrate, cholesterol, triglycerides and high-density lipoproteins to non-esterified fatty acids pre- and postpartum

Journal of Dairy Research ◽

10.1017/s0022029916000534 ◽

2016 ◽

Vol 83 (4) ◽

pp. 447-452

Author(s):

Julia Ruoff ◽

Sandra Bertulat ◽

Onno Burfeind ◽

Wolfgang Heuwieser

Keyword(s):

Lipid Metabolism ◽

Point Of Care ◽

Characteristic Curve ◽

High Sensitivity ◽

Receiver Operator Characteristic Curve ◽

Human Medicine ◽

High Density ◽

High Density Lipoproteins ◽

Nefa Concentration ◽

Point Of Care Test

While laboratory tests for measuring the concentration of NEFA in serum are well established, a point of care test to determine NEFA on farm is not available. Several hand-held measuring devices, however, have been validated for measuring β-hydroxybutyrate (BHBA) in cattle or cholesterol, triglycerides (TAG), and high-density lipoproteins (HDL) in human medicine, respectively. The objective of this study was to evaluate the association between NEFA and different parameters related to lipid metabolism. Specifically, we set out to determine if it is feasible to predict the concentration of NEFA by means of surrogate measures. The concentration of BHBA was determined by a hand-held device evaluated for use in cows, whereas the concentrations of the other parameters were determined by laboratory analysis because hand-held devices for cholesterol, TAG and HDL are only evaluated for human medicine so far. A total of 254 cows were included in the trial. One blood sample was taken from each cow between d 10 and d 1 prepartum. Second and third samples were collected on d 2 and d 10 postpartum, respectively. The coefficients of correlation between parameters were calculated and a receiver-operator characteristic curve analysis has been used. The prediction of NEFA concentrations using only one of the parameters was insufficient. However, a NEFA concentration ≥0·5 mEq/l could be predicted with a high sensitivity (i.e. Se = 0·88) and specificity (i.e. Sp = 0·93) from d 3 to d 1 prepartum and a NEFA concentration ≥0·7 mEq/l could be reliably predicted on d 2 postpartum (i.e. AUC = 0·89, Se = 0·89, Sp = 0·76) when using a combination of BHBA, cholesterol and TAG as surrogates. Overall, our results suggest that a combination of different parameters of lipid metabolism could be used as surrogates for NEFA.

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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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Two-Stage Isothermal Enzymatic Amplification for Concurrent Multiplex Molecular Detection

Clinical Chemistry ◽

10.1373/clinchem.2016.263665 ◽

2017 ◽

Vol 63 (3) ◽

pp. 714-722 ◽

Cited By ~ 38

Author(s):

Jinzhao Song ◽

Changchun Liu ◽

Michael G Mauk ◽

Shelley C Rankin ◽

James B Lok ◽

...

Keyword(s):

Point Of Care ◽

Healthcare Providers ◽

High Sensitivity ◽

Ease Of Use ◽

Isothermal Amplification ◽

Healthcare Personnel ◽

Highly Sensitive ◽

Simple Implementation ◽

Rapid Amplification ◽

High Level

Abstract BACKGROUND The wide array of pathogens responsible for infectious diseases makes it difficult to identify causative pathogens with single-plex tests. Although multiplex PCR detects multiple targets, it is restricted to centralized laboratories, which delays test results or makes multiplexing unavailable, depriving healthcare providers of critical, real-time information. METHODS To address the need for point-of-care (POC) highly multiplexed tests, we propose the 2-stage, nested-like, rapid (<40 min) isothermal amplification assay, dubbed rapid amplification (RAMP). RAMP's first-stage uses outer loop-mediated isothermal amplification (LAMP) primers to amplify all targets with recombinase polymerase amplification (RPA). First-stage amplicons are aliquoted to second stage reactors, each specialized for a specific target, to undergo LAMP. The assay is implemented in a microfluidic chip. LAMP amplicons are detected in situ with colorimetric dye or with a fluorescent dye and a smartphone. RESULTS In experiments on a benchtop and in a microfluidic format, RAMP demonstrated high level of multiplexing (≥16); high sensitivity (i.e., 1 plaque-forming unit of Zika virus) and specificity (no false positives or negatives); speed (<40 min); ease of use; and ability to cope with minimally processed samples. CONCLUSIONS RAMP is a hybrid, 2-stage, rapid, and highly sensitive and specific assay with extensive multiplexing capabilities, combining the advantages of RPA and LAMP, while circumventing their respective shortcomings. RAMP can be used in the lab, but one of its distinct advantages is amenability to simple implementation in a microfluidic format for use at the POC, providing healthcare personnel with an inexpensive, highly sensitive tool to detect multiple pathogens in a single sample, on site.

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Point-of-care tests for sexually transmissible infections: what do ‘end users' want?

Sexual Health ◽

10.1071/sh13047 ◽

2013 ◽

Vol 10 (6) ◽

pp. 541 ◽

Cited By ~ 19

Author(s):

Anne M. Rompalo ◽

Yu-Hsiang Hsieh ◽

Terry Hogan ◽

Mathilda Barnes ◽

Mary Jett-Goheen ◽

...

Keyword(s):

Qualitative Content Analysis ◽

Point Of Care ◽

High Sensitivity ◽

Advantages And Disadvantages ◽

Point Of Care Test ◽

Home Test ◽

Sexually Transmissible Infections ◽

Important Quality ◽

Point Of Care Tests ◽

At Home

Background Clinicians and developers identify sensitivity as an important quality in a point-of-care test (POCT) for sexually transmissible infections (STIs). Little information exists regarding what patients want for STI POCTs. Methods: A qualitative study, encompassing five focus groups among attendees of STI and adolescent health centres in Baltimore, Maryland, and Cincinnati, Ohio, were conducted between March 2008 and April 2009. Discussion topics included advantages and disadvantages of having a POCT, perceived barriers to using POCTs in the clinic setting and at home, priorities for the development of new POCTs for STIs, and envisioned characteristics of an ideal POCT. All discussions were recorded and transcribed. A qualitative content analysis was performed to examine frequencies or patterns of recurring codes, which were regrouped and indexed to identify salient themes. Results: Patients attending STI and adolescent outpatient clinics are in favour of diagnostic tests that are rapid, easy to read and simple to use. Home testing options for POCTs were acceptable and provided better confidentiality, privacy and convenience, but clinic-based POCTs were also acceptable because they offer definitive results and ensure immediate treatment. Barriers to home POCTs centred on cost and the ability to read and perform the test correctly at home. Opinions did not differ by patient ethnicity, except that Hispanic participants questioned the reliability of home test results, wanted high sensitivity and desired bilingual instructions. Conclusions: Patients attending STI and adolescent medical centres are in favour of STI POCTs if they are affordable, rapid, easy to read and simple to use.

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