Comparison of the use of comprehensive point-of-care test panel to conventional laboratory process in emergency department

Point-of-Care Tests' Role in Time Metrics of Urgent Interventions in Emergency Department; a Systematic Review of Literature

INTRODUCTION

Point-of-Care Testing (POCT) could be helpful in clinical decisions, treatment selection, monitoring, prognostication, operational decision-making, and resource utilization. This study aimed to review the role of POCT in time metrics of performing urgent interventions in the emergency department (ED) or disposition time to proper care.

METHODS

This was a systematic review of the literature based on the PRISMA statement. PubMed, Scopus, Web of Science, and EMBASE databases were searched for studies reporting the application of the POCT in the ED with outcomes of the time to intervention or disposition.

RESULTS

After reviewing 3708 articles, 16 studies with 100,224 participants were included in this systematic review. There were 5 randomized clinical trials (RCTs), 5 retrospective cohorts, 2 prospective cohorts, and 4 before-after studies. All studies were performed in an ED setting except for one study of prehospital EMS air medical transport. Different panels, ultrasound, cardiac parameters, echocardiography, and polymerase chain reaction (PCR) POCTs were used in the studies. Regarding the outcome measures, studies with many types of patients referring to ED used different indices of time to intervention or time to disposition. Studies on different shock circumstances used the time to the first bolus of hydration or vasopressor or intravenous antibiotics for septic shock patients and central venous catheterization (CVC) placement time in one study. Time to imaging was considered as the outcome in some studies. Overall, there was a high risk of bias, especially in case of the randomization methods, and non-blinded designs in RCTs. There was lower possibility of bias in non-randomized studies but the studies did not have enough follow-ups and in case of studies using advanced panels of POCT, results do not seem to be easily applicable to public health care in many countries.

CONCLUSION

In synthesis of the evidence, all included studies were reporting the benefits of the POCT in decreasing the time to proper interventions and increasing the time to negative interventions in the last lines of critical care as well as the intubation and CVC placement.

Recent developments on nanomaterial-based optical biosensor as potential Point-of-Care Testing (PoCT) probe in carcinoembryonic antigen detection: A review

For the past decades, several cancer biomarkers have been exploited for rapid and accurate prognosis or diagnosis purposes. In this review, the optical biosensor is targeted for carcinoembryonic antigen (CEA) detection. The CEA level is a prominent parameter currently used in clinical cases for the prognosis of cancer-related diseases. Many nanomaterial-based biosensors are invented as alternatives for the commonly used enzyme-linked immunosorbent assays (ELISA) immunoassay method in CEA detection as the traditional approach but they possess certain drawbacks such as tedious procedure, high technical demand, and costly. Nevertheless, the effort appears to be wasted as none of them are being actualised. Generally, the sensor function was carried out by converting bio-signals generated upon the interface of the receptor into light signals. These sensors were popular due to specific advantages such as sensitivity, being free from chemical and electromagnetic interferences, wide dynamic range, and being easy to be monitored. The features of PoC diagnostics are discussed and associated with the various applications of colorimetric-based and chemiluminescent-based biosensors. The roles of nanomaterials in each application were also summarised by comparing the modification, incubation period, lowest detection limit (LOD) and linear range of detection amount. The challenges and future perspectives were highlighted at the end of the review.

In-Situ Integration of 3D C-MEMS Microelectrodes with Bipolar Exfoliated Graphene for Label-Free Electrochemical Cancer Biomarkers Aptasensor

The electrochemical label-free aptamer-based biosensors (also known as aptasensors) are highly suitable for point-of-care applications. The well-established C-MEMS (carbon microelectromechanical systems) platforms have distinguishing features which are highly suitable for biosensing applications such as low background noise, high capacitance, high stability when exposed to different physical/chemical treatments, biocompatibility, and good electrical conductivity. This study investigates the integration of bipolar exfoliated (BPE) reduced graphene oxide (rGO) with 3D C-MEMS microelectrodes for developing PDGF-BB (platelet-derived growth factor-BB) label-free aptasensors. A simple setup has been used for exfoliation, reduction, and deposition of rGO on the 3D C-MEMS microelectrodes based on the principle of bipolar electrochemistry of graphite in deionized water. The electrochemical bipolar exfoliation of rGO resolves the drawbacks of commonly applied methods for synthesis and deposition of rGO, such as requiring complicated and costly processes, excessive use of harsh chemicals, and complex subsequent deposition procedures. The PDGF-BB affinity aptamers were covalently immobilized by binding amino-tag terminated aptamers and rGO surfaces. The turn-off sensing strategy was implemented by measuring the areal capacitance from CV plots. The aptasensor showed a wide linear range of 1 pM-10 nM, high sensitivity of 3.09 mF cm-2 Logc-1 (unit of c, pM), and a low detection limit of 0.75 pM. This study demonstrated the successful and novel in-situ deposition of BPE-rGO on 3D C-MEMS microelectrodes. Considering the BPE technique's simplicity and efficiency, along with the high potential of C-MEMS technology, this novel procedure is highly promising for developing high-performance graphene-based viable lab-on-chip and point-of-care cancer diagnosis technologies.

Advances in point-of-care testing for cardiovascular diseases

Point-of-care testing (POCT) is a specific format of diagnostic testing that is conducted without accompanying infrastructure or sophisticated instrumentation. Traditionally, such rapid sample-to-answer assays provide inferior analytical performances to their laboratory counterparts when measuring cardiac biomarkers. Hence, their potentially broad applicability is somewhat bound by their inability to detect clinically relevant concentrations of cardiac troponin (cTn) in the early stages of myocardial injury. However, the continuous refinement of biorecognition elements, the optimization of detection techniques, and the fabrication of tailored fluid handling systems to manage the sensing process has stimulated the production of commercial assays that can support accelerated diagnostic pathways. This review will present the latest commercial POC assays and examine their impact on clinical decision-making. The individual elements that constitute POC assays will be explored, with an emphasis on aspects that contribute to economically feasible and highly sensitive assays. Furthermore, the prospect of POCT imparting a greater influence on early interventions for medium to high-risk individuals and the potential to re-shape the paradigm of cardiovascular risk assessments will be discussed.

POCT: An Inherently Ideal Tool in Pediatric Laboratory Medicine

Point of care testing (POCT) is important in the provision of timely laboratory test results and continues to gain specific appreciation in the setting of pediatric healthcare. POCT platforms offer several advantages compared to central laboratory testing, including improved clinical outcomes, reduced time to diagnosis, length of stay, and blood volume requirements, as well as increased accessibility. These advantages are most pronounced in acute care settings such as pediatric emergency departments, intensive care units, and in remote settings, wherein rapid patient assessment and prognostication is essential to patient outcomes. The current review provides an overview and critical discussion of the evidence supporting clinical implementation of POCT systems in pediatric clinical decision-making, including but not limited to the diagnosis of viral and bacterial infection, identification of critical glucose and electrolyte dysregulation, and prognostication of post-operative inpatients. Important considerations for test result reporting and interpretation are also discussed, including analytical concordance between POCT systems and central laboratory analyzers as well as availability of pediatric reference intervals for key analytes on POCT systems. Notably, a paucity of evidence-based pediatric reference intervals for test interpretation for critical care parameters on POCT platforms is highlighted, warranting further study and unique consideration prior to clinical implementation.

Diagnostic Tests for COVID-19

The diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has ramifications on both an individual level and a public health level. The use of appropriate testing mechanisms is paramount to preventing transmission, along with offering treatment to those who are infected and show appropriate symptomatology. The choice of employing a specific test often relies on laboratory capabilities, including the abilities of the medical technologists, the cost of testing platforms, and the individual quirks of each test. This chapter intends to discuss the relevant issues relating to diagnostic testing for SARS-CoV-2, including specimen types and collection methods, viral detection methods, and serological testing.

Rapid and Electronic Identification and Quantification of Age-Specific Circulating Exosomes via Biologically Activated Graphene Transistors

Increasing access to modern clinical practices concomitantly extends lifespan, ironically revealing new classes of degenerative and inflammatory diseases of later years. Here, an electronic graphene field-effect transistor (gFET) is reported, termed EV-chip, for label-free, rapid identification and quantification of exosomes (EV) associated with aging through specific surface markers, CD63 and CD151. Studies suggest that blood-derived exosomes carry specific biomolecules that can be used toward diagnostic applications of age and health. However, to observe improvements in patient outcomes, earlier detection at the point-of-care (POC) is required. Unfortunately, conventional techniques and other electronic-based platforms for exosome sensing are burdensome and inept for the POC distinction of aged blood factors. It is shown that EV-chip can quantitatively detect purified exosomes from plasma, with a limit of detection (LOD) of 2 × 10⁴ particles mL^-1 and a limit of quantification (LOQ) of 6 × 10⁴ particles mL^-1 . The sensitivity and compact electronics of the EV-chip improves upon previously published electronic biosensors, making it ideal for a physician's office or a simple biological laboratory. The sensitivity, selectivity, and portability of the EV-chip demonstrate the potential of the biosensor as a powerful point-of-care diagnostic and prognostic tool for age-related diseases.

Point-of-Care Testing for the Emergency Department Patient: Quantity and Quality of the Available Evidence

CONTEXT.—

Point-of-care test (POCT) instruments produce lab results with rapid turnaround times. Based on that fact, emergency department (ED) POCT requests are predicated on the belief that rapid test turnaround times lead to improved care, typically a decreased ED length of stay (LOS).

OBJECTIVE.—

To compile the available peer-reviewed data regarding use of POCT in the ED with an emphasis on ED-LOS.

DATA SOURCES.—

An English-language PubMed search using the following free text terms: ("EMERGENCY" AND "POINT OF CARE") NOT ULTRASOUND as well as "RAPID INFECTIOUS DISEASE TESTING." In addition, the PubMed "similar articles" functionality was used to identify related articles that were not identified on the initial search.

CONCLUSIONS.—

Seventy-four references were identified that studied POCT ED use to determine if they resulted in significant changes in ED processes, especially ED-LOS. They were divided into 3 groups: viral-influenza (n = 24), viral-respiratory not otherwise specified (n = 8), and nonviral (n = 42). The nonviral group was further divided into the following groups: chemistry, cardiac, bacterial/strep, C-reactive protein, D-dimer, drugs of abuse, lactate, and pregnancy. Across all groups there was a trend toward a significantly decreased ED-LOS; however, a number of studies showed no change, and a third group was not assessed for ED-LOS. For POCT to improve ED-LOS it has to be integrated into existing ED processes such that a rapid test result will allow the patient to have a shorter LOS, whether it is to discharge or admission.

Current Status of Clinical Application of Point-of-Care Testing

CONTEXT.—

The clinical applications of point-of-care testing (POCT) are gradually increasing in many health care systems. Recently, POCT devices using molecular genetic method techniques have been developed. We need to examine clinical pathways to see where POCT can be applied to improve them.

OBJECTIVE.—

To introduce up-to-date POCT items and equipment and to provide the content that should be prepared for clinical application of POCT.

DATA SOURCES.—

Literature review based on PubMed searches containing the terms point-of-care testing, clinical chemistry, diagnostic hematology, and clinical microbiology.

CONCLUSIONS.—

If medical resources are limited, POCT can help clinicians make quick medical decisions. As POCT technology improves and menus expand, areas where POCT can be applied will also increase. We need to understand the limitations of POCT so that it can be optimally used to improve patient management.

Microfluidic Point-of-Care Testing: Commercial Landscape and Future Directions

Point-of-care testing (POCT) allows physicians to detect and diagnose diseases at or near the patient site, faster than conventional lab-based testing. The importance of POCT is considerably amplified in the trying times of the COVID-19 pandemic. Numerous point-of-care tests and diagnostic devices are available in the market including, but not limited to, glucose monitoring, pregnancy and infertility testing, infectious disease testing, cholesterol testing and cardiac markers. Integrating microfluidics in POCT allows fluid manipulation and detection in a singular device with minimal sample requirements. This review presents an overview of two technologies - (a.) Lateral Flow Assay (LFA) and (b.) Nucleic Acid Amplification - upon which a large chunk of microfluidic POCT diagnostics is based, some of their applications, and commercially available products. Apart from this, we also delve into other microfluidic-based diagnostics that currently dominate the in-vitro diagnostic (IVD) market, current testing landscape for COVID-19 and prospects of microfluidics in next generation diagnostics.

Predicting 30-day mortality using point-of-care testing; an external validation and derivation study

Background

Early risk stratification for guiding treatment priority in the emergency department (ED) is becoming increasingly important. Existing prediction models typically use demographics, vital signs and laboratory parameters. Laboratory-based models require blood testing, which may cause substantial delay. However, these delays can be prevented by the use of point-of-care testing (POCT), where results are readily available. We aimed to externally validate a laboratory-based model for mortality and subsequently assessed whether a POCT model yields comparable performance.

Methods

All adult patients visiting the ED of a university hospital between January 1^st, 2012 and December 31^st, 2016 were retrospectively reviewed for inclusion. Primary outcome was defined as 30-day mortality after ED presentation. We externally validated one existing prediction model including age, glucose, urea, sodium, haemoglobin, platelet count and white blood cell count. We assessed the predictive performance by discrimination, expressed as Area under the Curve (AUC). We compared the existing model to an equivalent model using predictors that are available with POCT (i.e. glucose, urea, sodium and haemoglobin). Additionally, we internally validated these models with bootstrapping.

Results

We included 34,437 patients of whom 1,942 (5.6%) died within 30 days. The AUC of the laboratory-based model was 0.794. We refitted this model to our ED population and found an AUC of 0.812, which decreased only slightly to 0.790 with only POCT parameters.

Conclusions

Our POCT-model performs similar to existing laboratory-based models in identifying patients at high risk for mortality, with results available within minutes. Although the model needs further validation and evaluation, it shows the potential of POCT for early risk stratification in the ED.

The Impact of Undetected In Vitro Hemolysis or Sample Contamination on Patient Care and Outcomes in Point-of-Care Testing: A Retrospective Study

BACKGROUND

Point-of-care (POC) testing is an integral diagnostic component in clinical settings like the emergency department (ED). However, most POC testing devices are unable to detect endogenous interferents such as hemolysis, which typically occurs during sample collection and handling and can falsely increase measured potassium (pseudohyperkalemia), a phenomenon we hypothesized may significantly impact patient care.

METHODS

In this retrospective study, we evaluated 100 unique admissions to the Oregon Health & Science University ED, presenting with elevated potassium measured at the POC. To evaluate whether in vitro hemolysis had occurred, POC test results were compared to repeat testing of the original specimen, or other specimens tested within 90 minutes in the Core laboratory. Review of associated Electronic Health Records determined whether elevated potassium initially measured using the POC analyzer was real, or due to in vitro hemolysis or contamination, and whether pseudohyperkalemia impacted patient management or care.

RESULTS

Of the 100 admissions with hyperkalemia measured using a POC analyzer, 40% were found to have pseudohyperkalemia due to hemolysis or contamination. Of these 40 patients, 6 experienced repeated testing, and an additional 5 were noted to have altered patient management, specifically due to pseudohyperkalemia.

CONCLUSIONS

This study demonstrates the incidence of in vitro hemolysis, which is unknown to the POC operator, is high in patients who show an elevated potassium as measured at the POC. Furthermore, in vitro hemolysis can significantly impact patient management, suggesting that minimizing the incidence of unrecognized hemolysis will benefit hospital efficiency, decrease waste, and improve patient care.

Perspectives On Blood-Based Point-Of-Care Diagnostics

Background

Point of Care (POC) diagnostics are an essential component of modern medicine and are employed in a variety of clinical disciplines to improve patient outcomes and provider efficiency. Despite these benefits, there are aspects of POC testing which may still hold room for improvement. In the present study, a group of healthcare professionals familiar with different facets of blood-based POC testing provided their perspectives on the benefits and challenges of POC testing within their respective fields.

Materials and methods

The study was conducted from April to June 2019, in Colorado, United States of America. Five healthcare professionals, each working in a distinct field (anesthesiology, nursing, emergency medicine, trauma surgery, and POC management) were interviewed. Results from each of the interviews were transcribed as qualitative perspectives on POC diagnostics.

Discussion

The general consensus among participants in this study is that POC testing is tremendously beneficial, providing rapid test results, increased access to diagnostics, and improvements in hospital efficiency. However, significant challenges remain in blood-based POC diagnostics, particularly in maintaining sample quality, due to the fact that devices used for sample acquisition and handling are not designed for POC. This raises the possibility for interferents like hemolysis to occur, which may alter diagnostic results. Errors in POC diagnostics, whether due to sample, operator, or instrument error, may cause providers to lose confidence in the test. This lack of confidence can lead to duplicate testing and delayed patient diagnoses.

Conclusion

The perspectives presented in this study suggest there is a significant need for improvement in the pre-analytical phase of POC testing, and that current practice employs specimen collection technology not designed for POC. Therefore, one hypothesis is that the introduction of a collection device designed specifically for POC could reduce pre-analytical errors, standardize sample quality, improve efficiency, and further benefit patient care.