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Paper-based point-of-care testing for diagnosis of dengue infections

Choi JR, Hu J, Wang S, Yang H, Wan Abas WA, Pingguan-Murphy B, et al.

Crit Rev Biotechnol, 2017 Feb;37(1):100-111.
PMID: 26912259

Dengue endemic is a serious healthcare concern in tropical and subtropical countries. Although well-established laboratory tests can provide early diagnosis of acute dengue infections, access to these tests is limited in developing countries, presenting an urgent need to develop simple, rapid, and robust diagnostic tools. Point-of-care (POC) devices, particularly paper-based POC devices, are typically rapid, cost-effective and user-friendly, and they can be used as diagnostic tools for the prompt diagnosis of dengue at POC settings. Here, we review the importance of rapid dengue diagnosis, current dengue diagnostic methods, and the development of paper-based POC devices for diagnosis of dengue infections at the POC.

Matched MeSH terms: Point-of-Care Testing*
Ease of use and validity testing of a point-of-care fast test for parasitic vaginosis self-diagnosis

Hawash Y, Jaafer N, Alpakistany T

Trop Biomed, 2021 Dec 01;38(4):491-498.
PMID: 35001916 DOI: 10.47665/tb.38.4.094

There is a demand for patients to self-diagnose their sexually transmitted infections (self- testing), particularly during the coronavirus pandemic to prevent infection spread. We enrolled a cohort of Saudi women in a single-visit prospective study, which was the first of its kind performed in the country. Our aim was to evaluate the OSOM® Trichomonas (OSOM) test, a single-use, point-of-care rapid test, for its efficacy and accessibility as a self-test for Trichomonas vaginalis (Trichomonas) infection. At a public hospital's gynecology clinic, women received sufficient training on specimen collection and OSOM self-testing. The women's infection status was re-evaluated using direct wet mount microscopy and clinician performed OSOM using additional swabs. Specimens with discordant results were sorted using an in- house polymerase chain reaction (PCR). 174 women aged 18 to 35 were registered and self- tested at the clinic under the supervision of a gynecologist between June and December 2020, with 84.4 percent (147/174) having a valid result on the first or repeat OSOM. Infection was detected in 12.2% (18/147) of participants, with two-thirds of them symptomatic. Young age, low education, the existence of vaginitis symptoms, and unemployment were identified as key risk factors for infection in the study population, with statistically significant differences seen among women only in terms of education level and employment status (p<0.001). The OSOM self-test performed well (83.3% sensitivity and 98.4% specificity), outperforming the wet mount microscopy (72.2% sensitivity and 100% specificity) and comparable to the clinicians' OSOM (88.8% sensitivity and 100% specificity). The patients' and clinicians' OSOM tests were strongly correlated, with a kappa of 0.89 and a 97.9% agreement. Self-collection of vaginal swabs was accepted and preferred by most women (94%) over the clinician-collection. Overall, our study's findings may have important consequences for the implementation of Trichomonas screening based on OSOM self-testing approach in the study's population.

Matched MeSH terms: Point-of-Care Testing*
Fulltext Study on ABO and RhD blood grouping: Comparison between conventional tile method and a new solid phase method (InTec Blood Grouping Test Kit)

Yousuf R, Abdul Ghani SA, Abdul Khalid N, Leong CF

Malays J Pathol, 2018 Apr;40(1):27-32.
PMID: 29704381 MyJurnal

INTRODUCTION: 'InTec Blood Grouping Test kit' using solid-phase technology is a new method which may be used at outdoor blood donation site or at bed side as an alternative to the conventional tile method in view of its stability at room temperature and fulfilled the criteria as point of care test. This study aimed to compare the efficiency of this solid phase method (InTec Blood Grouping Test Kit) with the conventional tile method in determining the ABO and RhD blood group of healthy donors.
METHODS: A total of 760 voluntary donors who attended the Blood Bank, Penang Hospital or offsite blood donation campaigns from April to May 2014 were recruited. The ABO and RhD blood groups were determined by the conventional tile method and the solid phase method, in which the tube method was used as the gold standard.
RESULTS: For ABO blood grouping, the tile method has shown 100% concordance results with the gold standard tube method, whereas the solid-phase method only showed concordance result for 754/760 samples (99.2%). Therefore, for ABO grouping, tile method has 100% sensitivity and specificity while the solid phase method has slightly lower sensitivity of 97.7% but both with good specificity of 100%. For RhD grouping, both the tile and solid phase methods have grouped one RhD positive specimen as negative each, thus giving the sensitivity and specificity of 99.9% and 100% for both methods respectively.
CONCLUSION: The 'InTec Blood Grouping Test Kit' is suitable for offsite usage because of its simplicity and user friendliness. However, further improvement in adding the internal quality control may increase the test sensitivity and validity of the test results.

Matched MeSH terms: Point-of-Care Testing*
Advances in paper-based sample pretreatment for point-of-care testing

Tang RH, Yang H, Choi JR, Gong Y, Feng SS, Pingguan-Murphy B, et al.

Crit Rev Biotechnol, 2016 Apr 14.
PMID: 27075621 DOI: 10.3109/07388551.2016.1164664

In recent years, paper-based point-of-care testing (POCT) has been widely used in medical diagnostics, food safety and environmental monitoring. However, a high-cost, time-consuming and equipment-dependent sample pretreatment technique is generally required for raw sample processing, which are impractical for low-resource and disease-endemic areas. Therefore, there is an escalating demand for a cost-effective, simple and portable pretreatment technique, to be coupled with the commonly used paper-based assay (e.g. lateral flow assay) in POCT. In this review, we focus on the importance of using paper as a platform for sample pretreatment. We firstly discuss the beneficial use of paper for sample pretreatment, including sample collection and storage, separation, extraction, and concentration. We highlight the working principle and fabrication of each sample pretreatment device, the existing challenges and the future perspectives for developing paper-based sample pretreatment technique.

Matched MeSH terms: Point-of-Care Testing
Point-of-Care Ultrasound Identification of Portal Vein Thrombosis in a Pediatric Patient

Ong YN, James V, Lau KS, Chor YK, Ong GY

Pediatr Emerg Care, 2022 Apr 01;38(4):183-186.
PMID: 34608058 DOI: 10.1097/PEC.0000000000002555

Abdominal pain is one of the most common presenting complaints encountered in the pediatric emergency department. The use of point-of-care ultrasonography by emergency physicians has been shown to expedite the diagnosis of a large variety of conditions and can be used to accurately identify intra-abdominal pathology in children. We describe the case of a pediatric patient who presented to the pediatric emergency department with acute abdominal pain, in whom point-of-care ultrasonography helped expedite the diagnosis of acute portal vein thrombosis and liver abscess.

Matched MeSH terms: Point-of-Care Testing
Aptamer-based 'point-of-care testing'

Gopinath SC, Lakshmipriya T, Chen Y, Phang WM, Hashim U

Biotechnol Adv, 2016 May-Jun;34(3):198-208.
PMID: 26876017 DOI: 10.1016/j.biotechadv.2016.02.003

Aptamers are single-stranded oligonucleotides that can be artificially generated by a method called Systematic evolution of ligands by exponential enrichment (SELEX). The generated aptamers have been assessed for high-performance sensing applications due to their appealing characteristics. With either aptamers alone or complementing with antibodies, several high sensitive and portable sensors have been demonstrated for use in 'point-of-care testing'. Due to their high suitability and flexibility, aptamers are conjugated with nanostructures and utilized in field applications. Moreover, aptamers are more amenable to chemical modifications, making them capable of utilization with most developed sensors. In this overview, we discuss novel, portable, and aptamer-based sensing strategies that are suitable for 'point-of-care testing'.

Matched MeSH terms: Point-of-Care Testing
Paper-based sample-to-answer molecular diagnostic platform for point-of-care diagnostics

Choi JR, Tang R, Wang S, Wan Abas WA, Pingguan-Murphy B, Xu F

Biosens Bioelectron, 2015 Dec 15;74:427-39.
PMID: 26164488 DOI: 10.1016/j.bios.2015.06.065

Nucleic acid testing (NAT), as a molecular diagnostic technique, including nucleic acid extraction, amplification and detection, plays a fundamental role in medical diagnosis for timely medical treatment. However, current NAT technologies require relatively high-end instrumentation, skilled personnel, and are time-consuming. These drawbacks mean conventional NAT becomes impractical in many resource-limited disease-endemic settings, leading to an urgent need to develop a fast and portable NAT diagnostic tool. Paper-based devices are typically robust, cost-effective and user-friendly, holding a great potential for NAT at the point of care. In view of the escalating demand for the low cost diagnostic devices, we highlight the beneficial use of paper as a platform for NAT, the current state of its development, and the existing challenges preventing its widespread use. We suggest a strategy involving integrating all three steps of NAT into one single paper-based sample-to-answer diagnostic device for rapid medical diagnostics in the near future.

Matched MeSH terms: Point-of-Care Testing*
Fulltext Diagnostic accuracy of rapid diagnostic tests for the early detection of leptospirosis

Alia SN, Joseph N, Philip N, Azhari NN, Garba B, Masri SN, et al.

J Infect Public Health, 2018 11 27;12(2):263-269.
PMID: 30502041 DOI: 10.1016/j.jiph.2018.10.137

BACKGROUND: Leptospirosis is often misdiagnosed with several other tropical febrile illnesses in Malaysia due to similarities in clinical manifestations. Although treatment regimens could be started based on clinical judgments, early diagnosis has become paramount as a guide to chemotherapeutic interventions. Confirmed laboratory diagnosis through MAT or PCR is time consuming and usually available only in reference laboratories and not practical in healthcare settings. Rapid and easy to perform diagnostic tests are widely used in these settings as the point of care diagnosis. The present study was undertaken to compare the diagnostic performance of two IgM based immunodiagnostic assay kits for acute leptospirosis.
METHODS: A total of 50 serum samples were collected from patients clinically suspected for acute leptospirosis on admission in the Hospital Serdang, from June 2016 to June 2017. All the samples were subjected to MAT, lipL32 PCR and the two rapid tests (Leptocheck-WB and ImmuneMed Leptospira IgM Duo Rapid test).
RESULTS: Out of the 50 clinically suspected patients sampled, 19 were confirmed positive for leptospirosis. Six (12%) were confirmed by MAT and 13 (26%) by PCR. Similarly, of the 50 clinically suspected cases, 17 (34%) showed positivity for Leptocheck-WB and 7 (14%) for ImmuneMed Leptospira IgM Duo Rapid test. The overall sensitivity and specificity was 47.37% and 80.65% for Leptocheck-WB, and 21.05% and 90.32% for ImmuneMed Leptospira IgM Duo Rapid test. In another set of previously confirmed MAT positive samples (1:400-1:3600) obtained from a reference laboratory, Leptocheck-WB showed higher sensitivity (90.72%) than ImmuneMed Leptospira IgM Duo Rapid test (40.21%), and comparable specificity for ImmuneMed Leptospira IgM Duo Rapid test (88.89%) and Leptocheck-WB (82.86%).
CONCLUSION: The sensitivity was higher for Leptocheck-WB and had a comparable specificity with ImmuneMed Leptospira IgM Duo Rapid test. Therefore, based on the present study, Leptocheck-WB is found to be a more sensitive rapid immunodiagnostic test for acute leptospirosis screening in hospital settings.

Matched MeSH terms: Point-of-Care Testing*
Fulltext Evaluation of the Diagnostic Accuracy of a New Biosensors-Based Rapid Diagnostic Test for the Point-Of-Care Diagnosis of Previous and Recent Dengue Infections in Malaysia

Chong ZL, Soe HJ, Ismail AA, Mahboob T, Chandramathi S, Sekaran SD

Biosensors (Basel), 2021 Apr 22;11(5).
PMID: 33921935 DOI: 10.3390/bios11050129

Dengue is a major threat to public health globally. While point-of-care diagnosis of acute/recent dengue is available to reduce its mortality, a lack of rapid and accurate testing for the detection of previous dengue remains a hurdle in expanding dengue seroepidemiological surveys to inform its prevention, especially vaccination, to reduce dengue morbidity. This study evaluated ViroTrack Dengue Serostate, a biosensors-based semi-quantitative anti-dengue IgG (immunoglobulin G) immuno-magnetic agglutination assay for the diagnosis of previous and recent dengue in a single test. Blood samples were obtained from 484 healthy participants recruited randomly from two communities in Petaling district, Selangor, Malaysia. The reference tests were Panbio Dengue IgG indirect and capture enzyme-linked immunosorbent assays, in-house hemagglutination inhibition assay, and focus reduction neutralization test. Dengue Serostate had a sensitivity and specificity of 91.1% (95%CI 87.8-93.8) and 91.1% (95%CI 83.8-95.8) for the diagnosis of previous dengue, and 90.2% (95%CI 76.9-97.3) and 93.2% (95%CI 90.5-95.4) for the diagnosis of recent dengue, respectively. Its positive predictive value of 97.5% (95%CI 95.3-98.8) would prevent most dengue-naïve individuals from being vaccinated. ViroTrack Dengue Serostate's good point-of-care diagnostic accuracy can ease the conduct of dengue serosurveys to inform dengue vaccination strategy and facilitate pre-vaccination screening to ensure safety.

Matched MeSH terms: Point-of-Care Testing*
Biosensing based on surface-enhanced Raman spectroscopy as an emerging/next-generation point-of-care approach for acute myocardial infarction diagnosis

Low JSY, Thevarajah TM, Chang SW, Goh BT, Khor SM

Crit Rev Biotechnol, 2020 Dec;40(8):1191-1209.
PMID: 32811205 DOI: 10.1080/07388551.2020.1808582

Cardiovascular disease is a major global health issue. In particular, acute myocardial infarction (AMI) requires urgent attention and early diagnosis. The use of point-of-care diagnostics has resulted in the improved management of cardiovascular disease, but a major drawback is that the performance of POC devices does not rival that of central laboratory tests. Recently, many studies and advances have been made in the field of surface-enhanced Raman scattering (SERS), including the development of POC biosensors that utilize this detection method. Here, we present a review of the strengths and limitations of these emerging SERS-based biosensors for AMI diagnosis. The ability of SERS to multiplex sensing against existing POC detection methods are compared and discussed. Furthermore, SERS calibration-free methods that have recently been explored to minimize the inconvenience and eliminate the limitations caused by the limited linear range and interassay differences found in the calibration curves are outlined. In addition, the incorporation of artificial intelligence (AI) in SERS techniques to promote multivariate analysis and enhance diagnostic accuracy are discussed. The future prospects for SERS-based POC devices that include wearable POC SERS devices toward predictive, personalized medicine following the Fourth Industrial Revolution are proposed.

Matched MeSH terms: Point-of-Care Testing*
Electrospin-coating of nitrocellulose membrane enhances sensitivity in nucleic acid-based lateral flow assay

Yew CT, Azari P, Choi JR, Li F, Pingguan-Murphy B

Anal Chim Acta, 2018 Jun 07;1009:81-88.
PMID: 29422135 DOI: 10.1016/j.aca.2018.01.016

Point-of-care biosensors are important tools developed to aid medical diagnosis and testing, food safety and environmental monitoring. Paper-based biosensors, especially nucleic acid-based lateral flow assays (LFA), are affordable, simple to produce and easy to use in remote settings. However, the sensitivity of such assays to infectious diseases has always been a restrictive challenge. Here, we have successfully electrospun polycaprolactone (PCL) on nitrocellulose (NC) membrane to form a hydrophobic coating to reduce the flow rate and increase the interaction rate between the targets and gold nanoparticles-detecting probes conjugates, resulting in the binding of more complexes to the capture probes. With this approach, the sensitivity of the PCL electrospin-coated test strip has been increased by approximately ten-fold as compared to the unmodified test strip. As a proof of concept, this approach holds great potential for sensitive detection of targets at point-of-care testing.

Matched MeSH terms: Point-of-Care Testing*
Improved sensitivity of lateral flow assay using paper-based sample concentration technique

Tang R, Yang H, Choi JR, Gong Y, Hu J, Feng S, et al.

Talanta, 2016 May 15;152:269-76.
PMID: 26992520 DOI: 10.1016/j.talanta.2016.02.017

Lateral flow assays (LFAs) hold great promise for point-of-care testing, especially in resource-poor settings. However, the poor sensitivity of LFAs limits their widespread applications. To address this, we developed a novel device by integrating dialysis-based concentration method into LFAs. The device successfully achieved 10-fold signal enhancement in Human Immunodeficiency Virus (HIV) nucleic acid detection with a detection limit of 0.1nM and 4-fold signal enhancement in myoglobin (MYO) detection with a detection limit of 1.56ng/mL in less than 25min. This simple, low-cost and portable integrated device holds great potential for highly sensitive detection of various target analytes for medical diagnostics, food safety analysis and environmental monitoring.

Matched MeSH terms: Point-of-Care Testing
Fulltext Development of loop-mediated isothermal amplification (LAMP) for the detection of speB gene in invasive Streptococcus pyogenes clinical isolates

Azi Simon Onyema, Leslie Than Thian Lung, Suresh Kumar, Rukman Awang Hamat

Malaysian Journal of Medicine and Health Sciences, 2019;15(106):1-1.
MyJurnal

Introduction: Group A streptococcus (GAS) is responsible for high morbidity and mortality globally. Hence, the need to develop sensitive, reliable and cost- effective method of detection is crucial. In this study, we developed a visual detection method for the common virulence gene, streptococcal pyrogenic exotoxin B (speB) involved in invasive GAS diseases using loop-mediated isothermal amplification (LAMP) with fluorescent detection dye (calcein). Meth-ods: The LAMP reaction was optimized at 63°C for 35 minutes using five sets of primer designed with LAMP primer V5 software. When the dye was added prior to amplification, samples with speB DNA developed a characteristic green color after the reaction, but no color reactions were observed in samples with DNAs of non-GAS isolates. De-tection of speB by LAMP assay was done among 43 clinical isolates of blood, pus, wound, tissue and throat samples and ATCCs for controls. Our findings were further reconfirmed by subjecting the LAMP products to 0.5% gel electro-phoresis. Results: The detection limit of this LAMP assay for speB was 10-7 ng/μl of genomic DNA per reaction, which was 10,000-fold more sensitive than conventional PCR 10-3 ng/μl. All 100 % samples were positive for speB gene by LAMP, and 93% by conventional PCR method. Conclusion: LAMP assay could offer remarkably high sensitivity, specificity, repeatability, reliability, affordability, and visibility; it is appropriate for rapid detection of speB in Group A streptococci (GAS) as a point of care testing.

Matched MeSH terms: Point-of-Care Testing
Seeing Is Believing: Ultrasound in Pediatric Procedural Performance

Fraga MV, Stoller JZ, Glau CL, De Luca D, Rempell RG, Wenger JL, et al.

Pediatrics, 2019 11;144(5).
PMID: 31615954 DOI: 10.1542/peds.2019-1401

Point-of-care ultrasound is currently widely used across the landscape of pediatric care. Ultrasound machines are now smaller, are easier to use, and have much improved image quality. They have become common in emergency departments, ICUs, inpatient wards, and outpatient clinics. Recent growth of supportive evidence makes a strong case for using point-of-care ultrasound for pediatric interventions such as vascular access (in particular, central-line placement), lumbar puncture, fluid drainage (paracentesis, thoracentesis, pericardiocentesis), suprapubic aspiration, and soft tissue incision and drainage. Our review of this evidence reveals that point-of-care ultrasound has become a powerful tool for improving procedural success and patient safety. Pediatric patients and clinicians performing procedures stand to benefit greatly from point-of-care ultrasound, because seeing is believing.

Matched MeSH terms: Point-of-Care Testing
Diagnostics and treatment of nerve agent poisoning-current status and future developments

Amend N, Niessen KV, Seeger T, Wille T, Worek F, Thiermann H

Ann N Y Acad Sci, 2020 11;1479(1):13-28.
PMID: 32198755 DOI: 10.1111/nyas.14336

Although 193 states have committed to the Chemical Weapons Convention and 98% of the declared chemical weapons stockpiles have been destroyed so far, nerve agent poisoning remains a lingering threat. The recent dissemination of sarin in Syria, the assassination of Kim Jong-Nam in Malaysia, and the assault on Sergei Skripal in the United Kingdom underline the need for effective treatment. The current therapeutic options of a muscarinic receptor antagonist, an oxime, and an anticonvulsant have been unchanged for decades. Therefore, new therapeutic strategies, for example, bioscavengers and receptor-active substances, are promising concepts that have to be examined for their benefits and limitations. In order to facilitate rapid diagnosis in challenging clinical situations, point-of-care diagnostics and detection are of importance. Therapeutic guidance concerning the duration and success of the current oxime therapy via determination of the cholinesterase status can contribute to an optimal use of resources. In summary, the challenges of current and future therapies for nerve agent poisoning and key diagnostic devices will be discussed.

Matched MeSH terms: Point-of-Care Testing
The role of a point-of-care ultrasound protocol in facilitating clinical decisions for snakebite envenomation in Taiwan: a pilot study

Ho CH, Ismail AK, Liu SH, Tzeng YS, Li LY, Pai FC, et al.

Clin Toxicol (Phila), 2021 Sep;59(9):794-800.
PMID: 33605805 DOI: 10.1080/15563650.2021.1881535

BACKGROUND: The incidence of acute compartment syndrome (ACS) following snakebite envenomation may be seriously overestimated in Taiwan. Snakebite-induced ACS is difficult to determine solely by clinical examination. Snakebite patients previously underwent surgical intervention based on speculation and general clinical examinations suggesting ACS presentations instead of direct intracompartmental pressure (IP) measurement prior to fasciotomy. Point-of-care ultrasound (POCUS) is a relatively widely available noninvasive tool. This study aimed to evaluate snakebite-envenomated patients for the presence of subcutaneous edema and diastolic retrograde arterial flow (DRAF).
MATERIALS AND METHODS: Snakebite patients were prospectively recruited between 2017 and 2019. All patients were examined with POCUS to locate edema and directly visualize and measure the arterial flow in the compressed artery. The presence of DRAF in the compressed artery is suggestive of ACS development because when compartment space restriction occurs, increased retrograde arterial flow is observed in the artery.
RESULTS: Twenty-seven snakebite patients were analyzed. Seventeen patients (63%) were bitten by Crotalinae snakes, seven (26%) by Colubridae, one (4%) by Elapidae, and two (7%) had unidentified snakebites. All Crotalinae bit patients received antivenom, had subcutaneous edema and lacked DRAF in a POCUS examination series.
DISCUSSION: POCUS facilitates clinical decisions for snakebite envenomation. We also highlighted that the anatomic site of the snakebite is an important factor affecting the prognosis of the wounds. There were limitations of this study, including a small number of patients and no comparison with the generally accepted invasive evaluation for ACS.
CONCLUSIONS: We are unable to state that POCUS is a valid surrogate measurement of ACS from this study but see this as a starting point to develop further research in this area. Further study will be needed to better define the utility of POCUS in patients envenomated by snakes throughout the world.

Matched MeSH terms: Point-of-Care Testing/standards*
Fulltext Diagnosis of severe dengue: Challenges, needs and opportunities

Wong PF, Wong LP, AbuBakar S

J Infect Public Health, 2020 Feb;13(2):193-198.
PMID: 31405788 DOI: 10.1016/j.jiph.2019.07.012

BACKGROUND: Delayed diagnosis of dengue cases with increased risk for severe disease could lead to poor disease outcome. To date there is no specific laboratory diagnostic test for severe dengue. This qualitative study explored expert views regarding current issues in diagnosing severe dengue, rationale for severe dengue-specific diagnostics, future prospects and features of potential diagnostics for severe dengue.
METHODS: In-depth individual interviews with thematic saturation were conducted between May and July 2018. The data was analyzed using thematic analysis.
RESULTS: Based on expert opinion, diagnosis of severe dengue is challenging as it depends on astute clinical interpretation of non-dengue-specific clinical and laboratory findings. A specific test that detects impending manifestation of severe dengue could 1) overcome failure in identifying severe disease for referral or admission, 2) facilitate timely and appropriate management of plasma leakage and bleeding, 3) overcome the lack of clinical expertise and laboratory diagnosis in rural health settings. The most important feature of any diagnostics for severe dengue is the point-of-care (POC) format where it can be performed at or near the bedside.
CONCLUSION: The development of diagnostics to detect impending severe dengue is warranted to reduce the morbidity and mortality rates of dengue infection and it should be prioritized.

Matched MeSH terms: Point-of-Care Testing
Deriving the optimal limit of detection for an HCV point-of-care test for viraemic infection: analysis of a global dataset

Morgan Freiman J, Wang J, Easterbrook PJ, Robert Horsburgh C, Marinucci F, White LF, et al.

J Hepatol, 2019 Feb 20.
PMID: 30797050 DOI: 10.1016/j.jhep.2019.02.011

BACKGROUND & AIMS: Affordable point-of-care (POC) tests for hepatitis C (HCV) viraemia are needed to improve access to treatment in low and middle income countries (LMICs). Our aims were to determine the target limit of detection (LOD) necessary to diagnose the majority of persons with HCV eligible for treatment, and identify characteristics associated with low-level viraemia (LLV) (defined as the lowest 3% of the distribution of HCV RNA) to understand those at risk of being mis-diagnosed.
METHODS: We established a multi-country cross-sectional dataset of first available quantitative HCV RNA linked to demographic and clinical data. We excluded individuals on HCV treatment. We analyzed the distribution of HCV RNA and determined critical thresholds for detection of HCV viraemia. We then performed logistic regression to evaluate factors associated with LLV, and derived relative sensitivities for significant covariates.
RESULTS: The dataset included 66,640 individuals with HCV viraemia from Georgia (44.4%), Canada (40.9%), India (8.1%), Cambodia (2.6%), Egypt (1.6%), Pakistan (1.3%), Cameroon (0.4%), Indonesia (0.2%), Thailand (0.2%), Vietnam (0.1%), Malaysia (0.05%), and Mozambique (0.02%). The 97% LOD was 1,318 IU/mL (95% CI 1298.4, 1322.3). Factors associated with LLV were younger age 18-30 vs. 51-64 years (OR 2.56 95% CI 2.19, 2.99), female vs. male sex (OR 1.32, 95% CI 1.18, 1.49), and advanced fibrosis stage F4 vs. F0-1 (OR 1.44, 95%CI 1.21, 1.69). Only the younger age group had a decreased relative sensitivity below 95% at 93.3%.
CONCLUSIONS: In this global dataset, a test with an LOD of 1,318 IU/mL would identify 97% of viraemic HCV infections among almost all populations. This LOD will help guide manufacturers in the development of affordable POC diagnostics to expand HCV testing and linkage to care in LMICs.
LAY SUMMARY: We created and analyzed a dataset from 12 countries with 66,640 participants with chronic hepatitis C virus infection. We determined that about 97% of those with viraemic infection had 1300 International Units/mL or more of circulating virus at the time of diagnosis. While current diagnostic tests can detect as little as 12 International Units/mL of virus, our findings suggest that increasing the level of detection closer to 1300 would maintain good test accuracy and will likely allow for more affordable portable tests to be developed for use in low and middle income countries.

Matched MeSH terms: Point-of-Care Testing
Future Priorities in Tackling Infections Due to Brain-Eating Amoebae

Khan NA, Anwar A, Siddiqui R

ACS Chem Neurosci, 2017 11 15;8(11):2355.
PMID: 28933530 DOI: 10.1021/acschemneuro.7b00343

Brain-eating amoebae (Acanthamoeba spp., Balamuthia mandrillaris, and Naegleria fowleri) can cause opportunistic infections involving the central nervous system. It is troubling that the mortality rate is more than 90% despite advances in antimicrobial chemotherapy over the last few decades. Here, we describe urgent key priorities for improving outcomes from infections due to brain-eating amoebae.

Matched MeSH terms: Point-of-Care Testing
Fulltext Gold-Hybridized Zinc Oxide Nanorods as Real-Time Low-Cost NanoBiosensors for Detection of virulent DNA signature of HPV-16 in Cervical Carcinoma

Ramesh T, Foo KL, R H, Sam AJ, Solayappan M

Sci Rep, 2019 Nov 19;9(1):17039.
PMID: 31745139 DOI: 10.1038/s41598-019-53476-9

Detection of host integrated viral oncogenes are critical for early and point-of-care molecular diagnostics of virus-induced carcinoma. However, available diagnostic approaches are incapable of combining both cost-efficient medical diagnosis and high analytical performances. To circumvent this, we have developed an improved IDE-based nanobiosensor for biorecognition of HPV-16 infected cervical cancer cells through electrochemical impedance spectroscopy. The system is fabricated by coating gold (Au) doped zinc oxide (ZnO) nanorods interfaced with HPV-16 viral DNA bioreceptors on top of the Interdigitated Electrode (IDE) chips surface. Due to the concurrently improved sensitivity and biocompatibility of the designed nanohybrid film, Au decorated ZnO-Nanorod biosensors demonstrate exceptional detection of HPV-16 E6 oncogene, the cancer biomarker for HPV infected cervical cancers. This sensor displayed high levels of sensitivity by detecting as low as 1fM of viral E6 gene target. The sensor also exhibited a stable functional life span of more than 5 weeks, good reproducibility and high discriminatory properties against HPV-16. Sensor current responses are obtained from cultured cervical cancer cells which are close to clinical cancer samples. Hence, the developed sensor is an adaptable tool with high potential for clinical diagnosis especially useful for economically challenged countries/regions.

Matched MeSH terms: Point-of-Care Testing

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