Point-of-care Assay Research Articles

Natural Indigenous Paper Substrates for Colorimetric Bioassays in Portable Analytical Systems: Sustainable Solutions from the Rain Forests to the Great Plains.

Point-of-care (POC) devices can provide inexpensive, practical, and expedited solutions for applications ranging from biomedicine to environmental monitoring. This work reports on the development of low-cost microfluidic substrates for POC systems suitable for analytical assays, while also satisfying the need for social and environmentally conscious practices regarding circular economy, waste reduction, and the use of local resources. Thus, an innovative greener process to extract cellulose from plants including abaca, cotton, kozo, linen, and sisal, originating from different places around the world, is developed, and then the corresponding paper substrates are obtained to serve as platforms for POC assays. Hydrophobic wax is used to delineate channels that are able to guide solutions into chambers where the colorimetric assay for total cholesterol quantification is carried out as a proof of concept. Morphological and physicochemical analyses are performed, including the evaluation of fiber diameter, shape and density, and mechanical and thermal properties, together with peel adhesion of the printed wax channels. Contact angle and capillary flow tests ascertain the suitability of the substrates for liquid assays and overall viability as low-cost, sustainable microfluidic substrates for POC applications.

Post-Assay Chemical Enhancement for Highly Sensitive Lateral Flow Immunoassays: A Critical Review.

Lateral flow immunoassay (LFIA) has found a broad application for testing in point-of-care (POC) settings. LFIA is performed using test strips-fully integrated multimembrane assemblies containing all reagents for assay performance. Migration of liquid sample along the test strip initiates the formation of labeled immunocomplexes, which are detected visually or instrumentally. The tradeoff of LFIA's rapidity and user-friendliness is its relatively low sensitivity (high limit of detection), which restricts its applicability for detecting low-abundant targets. An increase in LFIA's sensitivity has attracted many efforts and is often considered one of the primary directions in developing immunochemical POC assays. Post-assay enhancements based on chemical reactions facilitate high sensitivity. In this critical review, we explain the performance of post-assay chemical enhancements, discuss their advantages, limitations, compared limit of detection (LOD) improvements, and required time for the enhancement procedures. We raise concerns about the performance of enhanced LFIA and discuss the bottlenecks in the existing experiments. Finally, we suggest the experimental workflow for step-by-step development and validation of enhanced LFIA. This review summarizes the state-of-art of LFIA with chemical enhancement, offers ways to overcome existing limitations, and discusses future outlooks for highly sensitive testing in POC conditions.

Clinical assessment of a point-of-care assay to determine protective vaccinal antibody titers to canine viral diseases

Guidelines recommend that dogs are vaccinated for canine distemper virus (CDV), canine parvovirus (CPV), and canine adenovirus (CAV) every 3 years. Alternatively, their antibody titers are measured and vaccines given when titers fall below a protective threshold. In this study, a point-of-care (POC) assay was compared to hemagglutination inhibition (for CPV) and virus neutralization (for CAV and CDV) assays to predict the need for revaccination Ninety-two dogs presented for vaccination were enrolled. The POC assay indicated protective titers against CDV in 79/80, CPV in 89/90, and CAV in 91/91 dogs with reference standard antibody measurements that were over a protective threshold. The sensitivity of the POC assay for to detect protective concentrations of CDV antibodies was 99% (95% confidence interval [CI 95%], 93.3–99.9%). Ten dogs were falsely considered protected against CDV by the POC assay with a specificity of 17% (CI 95%, 3.0–44.8%). The sensitivity of the POC assay for protective concentrations of CPV titers was 99% (CI 95%, 93.9–99.9%). The sensitivity of the POC assay to detect protective concentrations of CAV antibodies was 100% (CI 95%, 95.9–100%). Only classifying high-positive CDV and CPV titers on the POC assay as protective improved assay specificity to 100%, but sensitivity decreased to 51% and 76% respectively. This POC assay had a high sensitivity for the detection of protective antibody titers; however, some dogs were falsely categorized as protected, especially for CDV.

Simultaneous Quantitative SARS-CoV-2 Antigen and Host Antibody Detection and Pre-Screening Strategy at the Point of Care.

As COVID-19 pandemic public health measures are easing globally, the emergence of new SARS-CoV-2 strains continue to present high risk for vulnerable populations. The antibody-mediated protection acquired from vaccination and/or infection is seen to wane over time and the immunocompromised populations can no longer expect benefit from monoclonal antibody prophylaxis. Hence, there is a need to monitor new variants and its effect on vaccine performance. In this context, surveillance of new SARS-CoV-2 infections and serology testing are gaining consensus for use as screening methods, especially for at-risk groups. Here, we described an improved COVID-19 screening strategy, comprising predictive algorithms and concurrent, rapid, accurate, and quantitative SARS-CoV-2 antigen and host antibody testing strategy, at point of care (POC). We conducted a retrospective analysis of 2553 pre- and asymptomatic patients who were tested for SARS-CoV-2 by RT-PCR. The pre-screening model had an AUC (CI) of 0.76 (0.73-0.78). Despite being the default method for screening, body temperature had lower AUC (0.52 [0.49-0.55]) compared to case incidence rate (0.65 [0.62-0.68]). POC assays for SARS-CoV-2 nucleocapsid protein (NP) and spike (S) receptor binding domain (RBD) IgG antibody showed promising preliminary results, demonstrating a convenient, rapid (<20 min), quantitative, and sensitive (ng/mL) antigen/antibody assay. This integrated pre-screening model and simultaneous antigen/antibody approach may significantly improve accuracy of COVID-19 infection and host immunity screening, helping address unmet needs for monitoring vaccine effectiveness and severe disease surveillance.

Development of a novel immunoFET technology-based POC assay for detection of Leishmania donovani and Leishmania major.

Leishmaniasis is considered as one of the 20 neglected tropical diseases. Current methods of leishmanial diagnosis depend on conventional laboratory-based techniques, which are time-consuming, costly and require special equipment and trained personnel. In this context, we aimed to provide an immuno field effect transistors (ImmunoFET) biosensor that matches the conventional standards for point-of-care (POC) monitoring and detection of Leishmania (L.) donovani/Leishmania major. Crude antigens prepared by repeated freeze thawing of L. donovani/L. major stationary phase promastigotes were used for ELISA and ImmunoFETs. Lesishmania-specific antigens were serially diluted in 1× PBS from a concentration of 106 -102 parasites/mL. A specific polyclonal antibody-based sandwich ELISA was established for the detection of Leishmania antigens. An immunoFET technology-based POC novel assay was constructed for the detection of Leishmania antigens. Interactions between antigen-antibody at the gate surface generate an electrical signal that can be measured by semiconductor field-effect principles. Sensitivity was considered and measured as the change in current divided by the initial current. The final L. donovani/L. major crude antigen protein concentrations were measured as 1.50 mg/mL. Sandwich ELISA against the Leishmania 40S ribosomal protein detected Leishmania antigens could detect as few as 100 L. donovani/L. major parasites. An immunoFET biosensor was constructed based on the optimization of aluminium gallium nitride/gallium nitride (AlGaN/GaN) surface oxidation methods. The device surface was composed by an AlGaN/GaN wafer with a 23 nm AlGaN barrier layer, a 2 μm GaN layer on the silicon carbide (SiC) substrate for Leishmania binding, and coated with a specific antibody against the Leishmania 40S ribosomal protein, which was successfully detected at concentrations from 106 to 102 parasites/mL in 1× PBS. At the concentration of 104 parasites, the immunoFETs device sensitivities were 13% and 0.052% in the sub-threshold regime and the saturation regime, respectively. Leishmania parasites were successfully detected by the ImmunoFET biosensor at a diluted concentration as low as 150 ng/mL. In this study, the developed ImmunoFET biosensor performed well. ImmunoFET biosensors can be used as an alternative diagnostic method to ELISA. Increasing the sensitivity and optimization of immuno-FET biosensors might allow earlier and faster detection of leishmaniasis.

Performance Evaluation of AFIAS ST2 and Ichroma ST2 Assays in Comparison with Presage ST2 Assay.

Elevated soluble suppression of tumorigenicity 2 (sST2) levels may predict mortality in heart failure (HF) patients. The AFIAS ST2 assay (AFIAS ST2, Boditech Med Inc., Chuncheon, Korea) and ichroma ST2 assay (ichroma ST2, Boditech Med Inc.) are newly developed point-of-care (POC) assays for measuring sST2 level. We evaluated the performance of these assays, in terms of cut-off validation and prognosis, and compared them with that of the Presage ST2 assay (Presage ST2, Critical Diagnostics, San Diego, CA, USA). We validated the US FDA-claimed sST2 clinical cut-off of 35 ng/mL using 420 serum samples (298 samples from the universal sample bank of the American Association for Clinical Chemistry and 122 samples from reference individuals from Konkuk University Medical Center). We compared AFIAS ST2 and ichroma ST2 with Presage ST2, using 206 samples from patients with HF. We assessed prognosis using the three assays in 252 samples from the Barcelona ambulatory HF cohort subsets. The upper reference limits of AFIAS ST2 and ichroma ST2 were within the clinical cut-off of Presage ST2. The results of AFIAS ST2 and ichroma ST2 were highly correlated with those of Presage ST2 (r = 0.82 and 0.81, respectively). Based on this cut-off, all three assays predicted cardiovascular death. The new POC assays, AFIAS ST2 and ichroma ST2, would be useful in clinical practice for managing HF patients, with performances equivalent to that of Presage ST2.

Electrophoretic Assembly of Antibody–Antigen Complexes Facilitates 1000 Times Improvement in the Limit of Detection of Serological Paper-Based Assay

Serological assays detect the presence of specific antibodies in blood. There are urgent and important applications for serological point-of-care (POC) assays. However, available detection methods are either insufficiently sensitive or too complex for POC settings. Here, we demonstrate that lateral flow immunoassay (LFIA), which is arguably the simplest universal molecular detection approach, can serve as a methodological platform for highly sensitive serological POC assays if combined with a simple, fast, and inexpensive electrophoretic step. In this work, we compared such electrophoretically driven LFIA (eLFIA) with conventional LFIA for the detection of immunoglobulins G against hepatitis B and C in serum. The limit of detection of eLFIA was proven to be 1000 times lower than that of conventional LFIA and sufficiently low to support clinical serological tests. eLFIA takes less than 10 min, requires only a minor accessory powered by a small 9 V battery, and can be performed by an untrained person in the POC environment using a 3 μL specimen of finger-prick capillary blood.

Evaluation of Leptospira infection and exposure in free-roaming cat populations in northern California and southern Texas.

Leptospirosis is a re-emergent zoonotic bacterial disease associated with renal and hepatic injury. In free-roaming cats in some regions, a high prevalence of Leptospira antibodies has been identified, and pathogenic leptospires have been detected in renal tissue, indicating that they may play a role in Leptospira epidemiology. The objective of this study was to determine the prevalence of Leptospira seroreactivity and urinary shedding of Leptospira DNA in free-roaming cats from northern California and southern Texas. A secondary objective was to compare the results of a point-of-care (POC) assay, designed to detect Leptospira antibodies, with the results of the microscopic agglutination test (MAT) when applied to serum samples from feral cats. Specimens were obtained from free-roaming cats from northern California (n = 52; 2020) and southern Texas (n = 75; 2017). Leptospira quantitative PCR was performed on blood and urine specimens from Californian cats. Serum samples from Californian and Texan cats were subjected to MAT to categorize them as Leptospira antibody-positive or antibody-negative. The performance of the POC assay was assessed using the MAT as the gold standard. Leptospira DNA was not detected in the blood or urine of any cats tested. The results of the MAT were positive in 17.3% (n = 9) of Californian cats and 10.7% (n = 8) of Texan cats (P = 0.3). The median MAT titer was 1:100 (range 1:100-1:200) in Californian cats and 1:200 (range 1:100-1:800) in Texan cats. The POC assay was negative in all specimens. Free-roaming cats in California and Texas are exposed to Leptospira species and may have the potential to act as sentinel hosts. No cats had evidence of current infection, as determined using PCR on blood and urine specimens. The POC test did not reliably detect anti-Leptospira antibodies in these cats. The role of cats in the maintenance or shedding of pathogenic leptospires requires further investigation.

Point-of-care urine tenofovir testing to predict HIV drug resistance among individuals with virologic failure.

We sought to evaluate the utility of a point-of-care (POC) urine tenofovir (TFV) assay, developed to objectively assess adherence, to predict HIV drug resistance (HIVDR) in people failing first-line antiretroviral therapy (ART). We retrospectively analyzed TFV levels as a biomarker of adherence in urine specimens collected during a clinical trial that enrolled adults with virologic failure on first-line ART in Uganda and South Africa. Urine specimens were analyzed from participants on TFV-containing regimens who had a viral load >1000 copies/ml and paired genotypic resistance test (GRT) results. We assessed recent ART TFV adherence with a qualitative POC lateral flow urine assay with a cut-off value of 1500 ng/ml. We then calculated performance characteristics of the POC urine TFV assay to predict HIVDR, defined as intermediate or high-level resistance to any component of the current ART regimen. Urine specimens with paired plasma GRT results were available from 283 participants. The most common ART regimen during study conduct was emtricitabine, tenofovir disoproxil fumarate, and efavirenz. The overall prevalence of HIVDR was 86% ( n = 243/283). Of those with TFV detected on the POC assay, 91% ( n = 204/224) had HIVDR, vs. only 66% ( n = 39/59) among those with no TFV detected ( P- value < 0.001). Positive and negative predictive values of the assay to predict HIVDR were 91% and 34%, respectively. In populations with a high prevalence of HIVDR, the POC urine TFV assay can provide a low-cost, rapid method to guide requirements for confirmatory resistance testing and inform the need for regimen change.

Analytical performance comparing siemens whole blood point of care Atellica VTLi to the central laboratory plasma Atellica IM high-sensitivity cardiac troponin I assays

IntroductionThis study examined the analytical performance of a whole blood (WB) point of care (POC) hs-cTnI assay compared to a plasma central laboratory hs-cTnI assay in patients presenting with ischemic symptoms to a US emergency department. MethodsFresh WB specimens collected at 0 and 2 h from 1089 consecutive patients (2152 total from 1076 matched specimens) were analyzed for hs-cTnI using WB on POC Siemens Atellica VTLi assay and plasma on central laboratory Siemens Atellica IM assay. Concordances were determined based on concentrations ranging from < limit of detection (LoD), LoD to overall and sex specific 99th percentiles from both the IFCC manufacturer package inserts and Universal Sample Bank (USB) data, and > 99th percentiles. Method comparisons were calculated using Passing Bablok regression and Bland Altmann plots, and linear regression determined by Pearson correlation coefficient. ResultsBaseline concentration comparisons showed: POC VTLi < LoD 4–5 %, ≥ LoD 95 %; Atellica IM < LoD 5–7 %, and ≥ LoD 94–95 %. From the 2152 paired 0 and 2-hour samples, based on 99th percentiles, overall concordance was 91–92 % (kappa 0.72–0.77) and discordance 8 %. Passing Bablok regression analysis using 1924 specimens between LoD to 500 ng/L showed: slopes 0.469–0.490; y-intercepts 1.753–2.028; r values 0.631–0.817. Pearson correlation coefficient showed moderate to strong correlation strength, even with up to 53 % cTnI concentrations variance (Passing Bablok slopes) vs 27.0–40.1 % (Bland-Altmann plots). ConclusionsUp to 95 % of measured samples were > LoD for both the POC (Atellica VTLi) and central laboratory (Atellica IM) hs-cTnI assays. Moderate to strong concordance and correlation were observed between assays, despite up to 53 % variances in cTnI concentration.

Liposome-based high-throughput and point-of-care assays toward the quick, simple, and sensitive detection of neutralizing antibodies against SARS-CoV-2 in patient sera

The emergence of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) in 2019 caused an increased interest in neutralizing antibody tests to determine the immune status of the population. Standard live-virus-based neutralization assays such as plaque-reduction assays or pseudovirus neutralization tests cannot be adapted to the point-of-care (POC). Accordingly, tests quantifying competitive binding inhibition of the angiotensin-converting enzyme 2 (ACE2) receptor to the receptor-binding domain (RBD) of SARS-CoV-2 by neutralizing antibodies have been developed. Here, we present a new platform using sulforhodamine B encapsulating liposomes decorated with RBD as foundation for the development of both a fluorescent, highly feasible high-throughput (HTS) and a POC-ready neutralizing antibody assay. RBD-conjugated liposomes are incubated with serum and subsequently immobilized in an ACE2-coated plate or mixed with biotinylated ACE2 and used in test strip with streptavidin test line, respectively. Polyclonal neutralizing human antibodies were shown to cause complete binding inhibition, while S309 and CR3022 human monoclonal antibodies only caused partial inhibition, proving the functionality of the assay. Both formats, the HTS and POC assay, were then tested using 20 sera containing varying titers of neutralizing antibodies, and a control panel of sera including prepandemic sera and reconvalescent sera from respiratory infections other than SARS-CoV-2. Both assays correlated well with a standard pseudovirus neutralization test (r = 0.847 for HTS and r = 0.614 for POC format). Furthermore, excellent correlation (r = 0.868) between HTS and POC formats was observed. The flexibility afforded by liposomes as signaling agents using different dyes and sizes can hence be utilized in the future for a broad range of multianalyte neutralizing antibody diagnostics.Graphical abstract

P149 Novel capillary blood point-of-care test for adalimumab and infliximab trough levels: Effects of abnormal blood conditions on the test result

Abstract Background Patients suffering from inflammatory bowel disease can be treated with the biologics adalimumab (ADL) or infliximab (IFX). Previous studies demonstrated the usefulness of therapeutic drug monitoring (TDM) to adjust the patient’s biologic concentration individually. Commercially available rapid assays support laboratories in the fast and easy detection of ADL and IFX concentrations but the assays’ dependency on serum as analyte matrix is a general hindrance for TDM, as serum preparation from whole blood is time-consuming and requires laboratory equipment. Patients and clinicians would thus benefit from rapid point-of-care (POC) and easy to use assays that are independent of laboratory equipment. The objective of this project was to expand existing serum lateral flow assays for the analysis of ADL or IFX in capillary blood and investigate potential interactions resulting from the blood matrix. Methods ADL and IFX lateral flow serum kits were optimized in such a way that both, capillary blood and EDTA whole blood can be used as analyte matrix by using disposable capillaries for blood collection and for its transfer into dropper bottles that are prefilled with chase buffer. To measure ADL or IFX levels with a POC lateral flow test cassette reader (BÜHLMANN Quantum Blue® Reader) the mixture is then applied on an ADL or IFX lateral flow test cassette. Matrix agreement studies were performed to compare spiked EDTA whole blood and capillary blood samples with serum as reference. Additionally, spiked EDTA whole blood samples were treated to obtain three abnormal blood conditions: Icteric, hemolytic and lipemic blood. Bias in results exceeding 30% relative difference to the untreated sample was considered as an interference. Results Spiked blood samples showed good agreement with reference serum samples. A bias of less than 15% at the clinical decision points for ADL (5 µg/mL and 12 µg/mL) and IFX (3 µg/mL and 7 µg/mL) was revealed. Observed relative differences between all tested abnormal blood conditions ranged between -20% and +26% for IFX and -16% and +5% for ADL. Conclusion Two POC assays for the determination of ADL or IFX in capillary blood or EDTA whole blood samples were successfully developed and can be used by healthcare professionals with time to results of only 15 minutes and without the need for additional laboratory equipment. No systematic interferences were detected with treated EDTA whole blood samples, which could appear when using blood as analyte matrix. The excellent agreement to serum trough levels shows that the POC adalimumab/infliximab capillary blood assays are ideal for therapeutic drug monitoring analysis at a clinician’s office or an infusion site.

Impact of hepatitis C virus point-of-care RNA viral load testing compared with laboratory-based testing on uptake of RNA testing and treatment, and turnaround times: a systematic review and meta-analysis

Point-of-care (POC) hepatitis C virus (HCV) RNA nucleic acid test viral load assays are being used increasingly as an alternative to centralised, laboratory-based standard-of-care (SOC) viral load assays to reduce loss to follow-up. We aimed to evaluate the impact of using POC compared with SOC approaches on uptake of HCV RNA viral load testing and treatment, and turnaround times from testing to treatment along the HCV care cascade. We searched PubMed, Embase, and Web of Science for studies published in English between Jan 1, 2016, and April 13, 2022. We additionally searched for accepted conference abstracts (2016-20) not identified in the main search. The contacts directory of the WHO Global Hepatitis Programme was also used to solicit additional studies on use of POC RNA assays. We included studies if they evaluated use of POC HCV RNA viral load with or without a comparator laboratory-based SOC assay, and had data on uptake of viral load testing and treatment, and turnaround times between these steps in cascade. We excluded studies with a sample size of ten or fewer participants. The POC studies were categorised according to whether the POC assay was based onsite at the clinic, in a mobile unit, or in a laboratory. Studies using the POC assay or comparator SOC assays were further stratified according to four models of care: whether HCV testing and treatment initiation were performed in the same or different site, and on the same or a different visit. The comparator was centralised, laboratory-based HCV RNA SOC assays. For turnaround times, we calculated the weighted median of medians with 95% CIs. We analysed viral load testing and treatment uptake using random-effects meta-analysis. The quality of evidence was rated using the GRADE framework. This study is registered with PROSPERO, CRD42020218239. We included 45 studies with 64 within-study arms: 28 studies were in people who inject drugs, were homeless, or both; four were in people incarcerated in prison; nine were in the general or mixed (ie, includes high-risk groups) populations; and four were in people living with HIV. All were observational studies. The pooled median turnaround times between HCV antibody test and treatment initiation was shorter with onsite POC assays (19 days [95% CI 14-53], ten arms) than with either laboratory-based POC assays (64 days [64-64], one arm) or laboratory-based SOC assays (67 days [50-67], two arms). Treatment uptake was higher with onsite POC assays (77% [95% CI 72-83], 34 arms) or mobile POC assays (81% [60-97], five arms) than with SOC assays (53% [31-75], 12 arms); onsite and mobile POC assay vs SOC assay p=0·029). For POC and SOC arms, higher RNA viral load testing uptake was seen with the same-site models for testing and treatment than with different-site models (all within-category p≤0·0001). For onsite and mobile POC arms, there was higher treatment uptake for same-site than different-site models (within-category p<0·0001). Four studies had direct within-study POC versus SOC comparisons for RNA viral load testing uptake (pooled relative risk 1·11 [95% CI 0·89-1·38]), and there were ten studies on treatment uptake (1·32 [1·06-1·64]). Overall, the quality of evidence was rated as low. Compared with use of laboratory-based SOC HCV viral load testing, the use of POC assays was associated with reduced time from antibody test to treatment initiation and increased treatment uptake. The effect of POC viral load testing is greatest when positioned within a simplified care model in which testing and treatment are provided at the same site, and, where possible, on the same day. POC HCV RNA viral load testing is now recommended in WHO guidelines as an alternative strategy to laboratory-based viral load testing. Unitaid.

Considering the Effects of Modern Point-of-Care Urine Biomarker Assays in Follow-Up of Patients with High-Risk Non-muscle-Invasive Bladder Cancer.

Although a plethora of urine markers for diagnosis and follow-up of patients with bladder cancer (BC) has been developed and studied, the clinical impact of urine testing on patient management remains unclear. The goal of this manuscript is to identify scenarios for a potential use of modern point-of-care (POC) urine marker assays in the follow-up of patients with high-risk non-muscle-invasive BC (NMIBC) and estimate potential risks and benefits. To permit comparison between different assays, the results of 5 different POC assays studied in a recent prospective multicenter study including 127 patients with suspicious cystoscopy undergoing TURB were used for this simulation. For the current standard of care (SOC), a "marker-enforced" procedure, and a combined strategy sensitivity (Se), estimated number of cystoscopies, and the numbers needed to diagnose (NND) over a 1-year follow-up period were calculated. For regular cystoscopy (SOC), a Se of 91.7% and a NND of 42.2 repetitive office cystoscopies (WLCs) for 1 recurrent tumor at 1year were calculated. For the "marker-enforced" strategy, marker sensitivities between 94.7% and 97.1% were observed. The "combined" strategy yielded for markers with a Se exceeding 50% an overall Se at 1year similar or superior to the current SOC. Savings regarding the number of cystoscopies in the "marker-enforced" strategy vs. the SOC were small, while, depending on the marker, up to 45% of all cystoscopies may be saved using the "combined" strategy. Based on the results of this simulation, a marker-supported follow-up of patients with high-risk (HR) NMIBC is safe and offers options to significantly reduce the number of cystoscopies without compromising the Se. Further research focusing on prospective randomized trials is needed to finally find a way to include marker results into clinical decision-making.

Acceptability of point of care testing for antipsychotic medication levels in schizophrenia

We surveyed 106 patients with schizophrenia who were being treated with either oral clozapine or oral aripiprazole. For each patient, the plasma level of the medication was measured using i) a venous blood sample and a conventional lab-based assay and ii) a novel point of care assay that used a capillary blood sample taken with a fingerprick. Immediately after providing the two samples, participants completed a brief questionnaire. We also surveyed 10 members of staff who were directly involved in the care of these patients. 98% of patients found the capillary point-of-care approach acceptable, and 85% preferred it to the conventional venous blood procedure. 78% of patients said it was useful to have access to the result at the point of care (as opposed to at a later date), and 90% felt that POC testing improved clinical care. 83% said that the POC test made them feel more involved in their treatment. 100% of staff said their experience with the POC test was good, that it was easier than venous collection, and that it was very useful to receive the medication level while the patient was still in the clinic. • POC test for antipsychotic medication levels was highly acceptable. • Most preferring it to conventional venous blood sampling. • Easier to introduce regular monitoring of antipsychotic medication levels. • Could improve the safety and effectiveness of all antipsychotic medications. • The acceptability of POC testing to patients is likely to make monitoring easier.

Point of care diagnosis of dry eye disease with a sensitive immunoassay for dual biomarker detection

Dry eye disease (DED) is a multifactorial eye disease with few effective methods for clinical diagnosis and treatment. It is the most common eye disease with significant health challenges of the unprecedented aging population. Recent proteomic studies and clinical research have led to the discovery of several biologically relevant biomarkers, with increased levels of Interleukin-6 (IL-6) and decreased levels of lactoferrin being clinically validated in the progression of DED. In this study, a sensitive point of care (POC) DED diagnostic method was developed for targeting dual biomarkers of IL-6 and lactoferrin in the tear samples. A paper-based lateral flow immunoassay (LFIA) was established in a double-antibody sandwich fashion with colloid gold nanoparticles acting as probes. The minimal detection concentrations were 0.1 ng/ml and 10 ng/ml for IL-6 and lactoferrin, respectively. Separated conventional ELISA tests were also performed with data confirming results from the LFIA tests. A trial study was conducted with 20 tear samples from DED patients and healthy controls. All DED tear samples exhibited significantly higher levels of IL-6 and decreased levels of lactoferrin, as compared to the normal controls. A quantitative analysis of LFIA images was carried out using ImageJ software for an accurate data interpretation. This dual biomarker detection method is sensitive and affordable with quick turnaround time. Design of a larger clinical study in the future can further validate this POC assay for early diagnosis as well as patients’ self-management of chronic states of DED.

A Cost Comparison Modeling Analysis for Healthcare Access and Equity: Cost of COVID-19 Test Screening by Point of Care (POC) Versus Rapid Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)

Abstract Introduction/Objective Testing platforms to detect COVID-19 infection include antigen-based point of care (POC) testing and reverse transcriptase polymerase chain reaction (RT-PCR) to detect viral ribonucleic acid (RNA). RT-PCR, generally considered the gold standard for diagnosis of COVID-19 infection, is capable of being used for mass population screening but may be more expensive. Alternatively, antigen based POC testing can not only produce results rapidly (15 minutes on some assays) but also may be less expensive. This reduced cost provides an argument that it may be economical to use POC testing for mass surveillance in asymptomatic or mildly symptomatic patients while reserving the more expensive gold standard RT-PCR testing for sensitivity for hospitalized and more significantly at risk or ill patients. However, cost modeling between the two modalities for mass screening is sparse, particularly for studies including the Veteran Affairs system that may have different costs from the general community retail pricing. Methods/Case Report Cost information reviewed at the regional VAMC included costs for the Alinity-m SARS-CoV-2 RT-PCR assay (Abbott, Chicago IL), the Cepheid Xpert-Xpress-CoV-2-Flu-RSV-Plus RT-PCR assay (Cepheid, Sunnyvale CA), and the BinaxNOW POC antigen-based assay (Abbott, Chicago IL). The median cost of RT-PCR testing in the community was obtained from the Peterson-KFF Health System Tracker. Publicly available quoted prices for selected POC assays in the community were reviewed for comparison. Results (if a Case Study enter NA) Test costs at the regional VAMC was $28.34 (Alinity-m), $68 (Cepheid), and $5 (BinaxNOW). These costs did not include technologist time or standard laboratory consumables that would be part of the standard overhead costs of running the laboratory. The median community RT-PCR assay price per the Peterson- KFF Health System Tracker was $148, and the Abbott’s quoted BinaxNOW price was $25. POC testing cost was 82% less than the cheapest RT-PCR assay available at the regional VAMC. This trend in being significantly cheaper holds true in the community whereby BinaxNOW testing was 83% cheaper. Publicly available quoted prices from other selected POC assays confirm this trend. Conclusion For a mass surveillance screening program, the use of POC assays would result in significant cost savings.

An Illustrative Model of Economically Utilizing Point of Care and Reverse Transcriptase Polymerase Chain Reaction Testing to Reduce Costs and Help Balance Supply and Demand

Abstract Introduction/Objective Both point of care (POC) antigen-based assays and reverse transcriptase polymerase chain reaction (RT-PCR) laboratory-based assays exist for diagnosis of COVID-19. COVID-19 RT-PCR tests are the gold standard based on their higher sensitivity. However, in this era of inflation and supply chain disruptions, the use of only RT-PCR tests would be more expensive and may be vulnerable to reagent supply chain shortages. Triage of resources of both test types is important in ensuring access and equity in testing distribution as well as ensuring economical RT-PCR testing access for sicker patients. A comparison of costs was explored by contrasting a model of cost effectively reserving RT-PCR tests for those with significant disease requiring hospitalization and using POC tests for those with mild disease (defined as at most mild symptoms not requiring hospitalization) versus universal provision of RT-PCR to all. Methods/Case Report Cost information from the regional Veteran Affairs Medical Center (VAMC), specifically for the Alinity-m (RT-PCR) and BinaxNOW (POC) by Abbott (Chicago IL), and from the community (median COVID-19 RT- PCR pricing obtained from the Peterson KFF Health System Tracker) were included. Based on this cost information, a model of 100 tested COVID-19 suspected patients was created. A percentage of mild disease not requiring hospitalization (81%) was utilized based on literature from early in the COVID-19 pandemic. Results (if a Case Study enter NA) The cost per test at VAMC factored in was $28.34 (Alinity-m) and $5 (BinaxNOW). The median community RT-PCR and POC price factored in was $148 and $25, respectively. From the model of 100 COVID-19 with a mild disease percentage of 81%, the total testing cost of including POC assays for mild cases vs. universal RT-PCR assays would be $943.46 vs. $2,834 at the VAMC and similarly $4,837 vs. $14,800 in the community for a 67% reduction in costs at both settings. Conclusion A model of testing including both POC and RT-PCR testing may be economical and critically help ensure triage of resources in this era of inflation and supply chain shortages.

A Lateral Flow Device for Point-of-Care Detection of Doxorubicin.

A simple, rapid, and sensitive point-of-care (POC) device for the on-site detection of doxorubicin was developed. The proposed method relies on the naked-eye detection of the intrinsic fluorescence of the drug in a lateral flow device (LFD) configuration, exploiting the biological recognition of DNA probes and avoiding the use of expensive antibodies and sophisticated instrumentations. The POC assay does not require any pre-treatment or purification step and provides an immediate visual readout, achieving a limit of detection as low as ca. 1 ng doxorubicin, outperforming several laboratory-based instrumental techniques. The POC method was proven useful for the detection of trace amounts of the drug both in the case of water solutions (to simulate surface contaminations) and in urine samples, opening promising perspectives for routine monitoring of doxorubicin, with potential benefit to healthcare workers and personalized chemotherapies.

Quantitative and rapid detection of morphine and hydromorphone at the point of care by an automated giant magnetoresistive nanosensor platform.

Opioids, such as morphine and hydromorphone, are common pain management drugs with a high risk for addiction and adverse effects when delivered in large doses or administered too frequently. Point-of-care (POC) tools provide a solution to combat these negative outcomes through active monitoring of opioid concentrations in clinical settings. We demonstrate that giant magnetoresistive (GMR) nanosensors offer a quantitative, sensitive, and rapid solution for low-cost, sample-to-answer opioid detection at the POC. We show the robust nature of GMR nanosensors by developing a competitive morphine assay and characterizing it in saliva, blood, and plasma. We then implemented the assay on a fully automated POC GMR platform and demonstrated its duality to detect either morphine or hydromorphone using only 180μL of direct saliva without the need for pre-processing. In 35min from sample addition to result, the automated platform was controlled via smartphone and had seamless transmission of results via Bluetooth. The fully automated POC assay had a limit of detection of 3.43ng/mL for morphine and 3.49ng/mL for hydromorphone. The low-cost, 80-plex GMR nanosensor array coupled with the automated POC platform enables future development of multiplexed drug screening tools that can be deployed in clinical settings using a wide variety of non-invasive matrices.