The Coronavirus Disease 2019 Spatial Care Path: Home, Community, and Emergency Diagnostic Portals

Geospatial Point-of-Care Testing Strategies for COVID-19 Resilience in Resource-Poor Settings: Rural Cambodia Field Study

BACKGROUND

Point-of-care testing (POCT) generates intrinsically fast, inherently spatial, and immediately actionable results. Lessons learned in rural Cambodia and California create a framework for planning and mobilizing POCT with telehealth interventions. Timely diagnosis can help communities assess the spread of highly infectious diseases, mitigate outbreaks, and manage risks.

OBJECTIVE

The aims of this study were to identify the need for POCT in Cambodian border provinces during peak COVID-19 outbreaks and to quantify geospatial gaps in access to diagnostics during community lockdowns.

METHODS

Data sources comprised focus groups, interactive learners, webinar participants, online contacts, academic experts, public health experts, and officials who determined diagnostic needs and priorities in rural Cambodia during peak COVID-19 outbreaks. We analyzed geographic distances and transit times to testing in border provinces and assessed a high-risk province, Banteay Meanchey, where people crossed borders daily leading to disease spread. We strategized access to rapid antigen testing and molecular diagnostics in the aforementioned province and applied mobile-testing experience among the impacted population.

RESULTS

COVID-19 outbreaks were difficult to manage in rural and isolated areas where diagnostics were insufficient to meet needs. The median transit time from border provinces (n=17) to testing sites was 73 (range 1-494) minutes, and in the high-risk Banteay Meanchey Province (n=9 districts), this transit time was 90 (range 10-150) minutes. Within border provinces, maximum versus minimum distances and access times for testing differed significantly (P<.001). Pareto plots revealed geospatial gaps in access to testing for people who are not centrally located. At the time of epidemic peaks in Southeast Asia, mathematical analyses showed that only one available rapid antigen test met the World Health Organization requirement of sensitivity >80%. We observed that in rural Solano and Yolo counties, California, vending machines and public libraries dispensing free COVID-19 test kits 24-7 improved public access to diagnostics. Mobile-testing vans equipped with COVID-19 antigen, reverse transcription polymerase chain reaction, and multiplex influenza A/B testing proved useful for differential diagnosis, public awareness, travel certifications, and telehealth treatment.

CONCLUSIONS

Rural diagnostic portals implemented in California demonstrated a feasible public health strategy for Cambodia. Automated dispensers and mobile POCT can respond to COVID-19 case surges and enhance preparedness. Point-of-need planning can enhance resilience and assure spatial justice. Public health assets should include higher-quality, lower-cost, readily accessible, and user-friendly POCT, such as self-testing for diagnosis, home molecular tests, distributed border detection for surveillance, and mobile diagnostics vans for quick telehealth treatment. High-risk settings will benefit from the synthesis of geospatially optimized POCT, automated 24-7 test access, and timely diagnosis of asymptomatic and symptomatic patients at points of need now, during new outbreaks, and in future pandemics.

Point-of-care testing: state-of-the art and perspectives

Point-of-care testing (POCT) is becoming an increasingly popular way to perform laboratory tests closer to the patient. This option has several recognized advantages, such as accessibility, portability, speed, convenience, ease of use, ever-growing test panels, lower cumulative healthcare costs when used within appropriate clinical pathways, better patient empowerment and engagement, and reduction of certain pre-analytical errors, especially those related to specimen transportation. On the other hand, POCT also poses some limitations and risks, namely the risk of lower accuracy and reliability compared to traditional laboratory tests, quality control and connectivity issues, high dependence on operators (with varying levels of expertise or training), challenges related to patient data management, higher costs per individual test, regulatory and compliance issues such as the need for appropriate validation prior to clinical use (especially for rapid diagnostic tests; RDTs), as well as additional preanalytical sources of error that may remain undetected in this type of testing, which is usually based on whole blood samples (i.e., presence of interfering substances, clotting, hemolysis, etc.). There is no doubt that POCT is a breakthrough innovation in laboratory medicine, but the discussion on its appropriate use requires further debate and initiatives. This collective opinion paper, composed of abstracts of the lectures presented at the two-day expert meeting "Point-Of-Care-Testing: State of the Art and Perspective" (Venice, April 4-5, 2024), aims to provide a thoughtful overview of the state-of-the-art in POCT, its current applications, advantages and potential limitations, as well as some interesting reflections on the future perspectives of this particular field of laboratory medicine.

Web-accessible critical limits and critical values for urgent clinician notification

OBJECTIVES

To survey the World Wide Web for critical limits/critical values, assess changes in quantitative low/high thresholds since 1990-93, streamline urgent notification practices, and promote global accessibility.

METHODS

We identified Web-posted lists of critical limits/values at university hospitals. We compared 2023 to 1990-93 archived notification thresholds.

RESULTS

We found critical notification lists for 26 university hospitals. Laboratory disciplines ranged widely (1-10). The median number of tests was 62 (range 21-116); several posted policies. The breadth of listings increased. Statistically significant differences in 2023 vs. 1990 critical limits were observed for blood gas (pO2, pCO2), chemistry (glucose, calcium, magnesium), and hematology (hemoglobin, platelets, PTT, WBC) tests, and for newborn glucose, potassium, pO2, and hematocrit. Twenty hospitals listed ionized calcium critical limits, which have not changed. Fourteen listed troponin (6), troponin I (3), hs-TnI (3), or troponin T (2). Qualitative critical values expanded across disciplines, encompassing anatomic/surgical pathology. Bioterrorism agents were listed frequently, as were contagious pathogens, although only three hospitals listed COVID-19. Only one notification list detailed point-of-care tests. Two children's hospital lists were Web-accessible.

CONCLUSIONS

Urgent notifications should focus on life-threatening conditions. We recommend that hospital staff evaluate changes over the past three decades for clinical impact. Notification lists expanded, especially qualitative tests, suggesting that automation might improve efficiency. Sharing notification lists and policies on the Web will improve accessibility. If not dependent on the limited scope of secondary sources, artificial intelligence could enhance knowledge of urgent notification and critical care practices in the 21st Century.

Lessons from the pandemic: new best practices in selecting molecular diagnostics for point-of-care testing of infectious diseases in sub-Saharan Africa

INTRODUCTION

Point-of-care molecular diagnostics offer solutions to the limited diagnostic availability and accessibility in resource-limited settings. During the COVID-19 pandemic, molecular diagnostics became essential tools for accurate detection and monitoring of SARS-CoV-2. The unprecedented demand for molecular diagnostics presented challenges and catalyzed innovations which may provide lessons for the future selection of point-of-care molecular diagnostics.

AREAS COVERED

We searched PubMed from January 2020 to August 2023 to identify lessons learned from the COVID-19 pandemic which may impact the selection of point-of-care molecular diagnostics for future use in sub-Saharan Africa. We evaluated this in the context of REASSURED criteria (Real-time connectivity; Ease of specimen collection; Affordable; Sensitive; Specific; User-friendly; Rapid and robust; Equipment free; and Deliverable to users at the point of need) for point-of-care diagnostics for resource-limited settings.

EXPERT OPINION

The diagnostic challenges and successes during the COVID-19 pandemic affirmed the importance of the REASSURED criteria but demonstrated that these are not sufficient to ensure new diagnostics will be appropriate for public health emergencies. Capacity for rapid scale-up of diagnostic testing and transferability of assays, data, and technology are also important, resulting in updated REST-ASSURED criteria. Few diagnostics will meet all criteria, and trade-offs between criteria will need to be context-specific.

Using geographic rescue time contours, point-of-care strategies, and spatial care paths to prepare island communities for global warming, rising oceans, and weather disasters

OBJECTIVES

To perform geographic contour analysis of sea and land ambulance rescue times in an archipelago subject to super typhoons; to design point-of-care testing strategies for medical emergencies and weather disasters made more intense by global warming and rising oceans; and to assess needs for prehospital testing on spatial care paths that accelerate decision making, increase efficiency, improve outcomes, and enhance standards of care in island nations.

METHODS

We performed needs assessments, inspected healthcare facilities, and collected ambulance rescue times from professionals in the Bantayan Archipelago, Philippines. We mapped sea/land ambulance rescue routes and time contours. To reveal gaps, we statistically compared the fastest and slowest patient rescue times from islands/islets and barangays to the District Hospital on Bantayan Island. We developed spatial care paths (the fastest routes to care) for acute myocardial infarction, community care, and infectious diseases. We generated a compendium of prehospital diagnostic testing and integrated outcomes evidence, diagnostic needs, and public health goals to recommend point-of-care strategies that build geographic health resilience.

RESULTS

We observed limited access to COVID-19 assays, absence of blood gas/pH testing for critical care support, and spatial gaps in land and airborne rescues that worsened during inclement weather and sea swells. Mean paired differences (slowest-fastest) in ambulance rescue times to the District Hospital for both islands and barangays were significant (P < 0.0001). Spatial care path analysis showed where point-of-care cardiac troponin testing should be implemented for expedited care of acute myocardial infarction. Geospatial strengths comprised distributed primary care that can be facilitated by point-of-care testing, logical interisland transfers for which decision making and triage could be accelerated with onboard diagnostics, and healthcare networks amenable to medical advances in prehospital testing that accelerate treatment.

CONCLUSIONS

Point-of-care testing should be positioned upstream close to homes and island populations that have prolonged rescue time contours. Geospatially optimized point-of-need diagnostics and distributed prehospital testing have high potential to improve outcomes. These improvements will potentially decrease disparities in mortality among archipelago versus urban dwellers, help improve island public health, and enhance resilience for increasingly adverse and frequent climate change weather disasters that impact vulnerable coastal areas. [350 words].

The Impact of Repeating COVID-19 Rapid Antigen Tests on Prevalence Boundary Performance and Missed Diagnoses

A prevalence boundary (PB) marks the point in prevalence in which the false omission rate, RFO = FN/(TN + FN), exceeds the tolerance limit for missed diagnoses. The objectives were to mathematically analyze rapid antigen test (RAgT) performance, determine why PBs are breeched, and evaluate the merits of testing three times over five days, now required by the US Food and Drug Administration for asymptomatic persons. Equations were derived to compare test performance patterns, calculate PBs, and perform recursive computations. An independent July 2023 FDA-NIH-university-commercial evaluation of RAgTs provided performance data used in theoretical calculations. Tiered sensitivity/specificity comprise the following: tier (1) 90%, 95%; tier (2) 95%, 97.5%; and tier (3) 100%, ≥99%. Repeating a T2 test improves the PB from 44.6% to 95.2% (RFO 5%). In the FDA-NIH-university-commercial evaluation, RAgTs generated a sensitivity of 34.4%, which improved to 55.3% when repeated, and then improved to 68.5% with the third test. With RFO = 5%, PBs are 7.37/10.46/14.22%, respectively. PB analysis suggests that RAgTs should achieve a clinically proven sensitivity of 91.0-91.4%. When prevalence exceeds PBs, missed diagnoses can perpetuate virus transmission. Repeating low-sensitivity RAgTs delays diagnosis. In homes, high-risk settings, and hotspots, PB breaches may prolong contagion, defeat mitigation, facilitate new variants, and transform outbreaks into endemic disease. Molecular diagnostics can help avoid these potential vicious cycles.

Optimizing Public Health Preparedness for Highly Infectious Diseases in Central Vietnam

Our primary objectives were (a) to determine the need for and the availability of point-of-care testing (POCT) for infectious diseases and (b) to recommend point-of-care testing strategies and Spatial Care Paths^TM (SCPs) that enhance public health preparedness in the regional districts of Thua Thien Hue Province (TTHP), Central Vietnam, where we conducted field surveys. Medical professionals in seven community health centers (CHCs), seven district hospitals (DHs) and one provincial hospital (PH) participated. Survey questions (English and Vietnamese) determined the status of diagnostic testing capabilities for infectious diseases and other acute medical challenges in TTHP. Infectious disease testing was limited: six of seven CHCs (86%) lacked infectious disease tests. One CHC (14%, 1/7) had two forms of diagnostic tests available for the detection of malaria. All CHCs lacked adequate microbiology laboratories. District hospitals had few diagnostic tests for infectious diseases (tuberculosis and syphilis), blood culture (29%, 2/7), and pathogen culture (57%, 4/7) available. The PH had broader diagnostic testing capabilities but lacked preparedness for highly infectious disease threats (e.g., Ebola, MERS-CoV, SARS, Zika, and monkeypox). All sites reported having COVID-19 rapid antigen tests; COVID-19 RT-PCR tests were limited to higher-tier hospitals. We conclude that infectious disease diagnostic testing should be improved and POC tests must be supplied near patients’ homes and in primary care settings for the early detection of infected individuals and the mitigation of the spread of new COVID-19 variants and other highly infectious diseases.