Patient Self-testing Research Articles

Update on Patient Self-Testing with Portable and Wearable Devices: Advantages and Limitations.

Laboratory medicine has undergone a deep and multifaceted revolution in the course of human history, in both organizational and technical terms. Over the past century, there has been a growing recognition of the need to centralize numerous diagnostic activities, often similar or identical but located in different clinical departments, into a common environment (i.e., the medical laboratory service), followed by a progressive centralization of tests from smaller laboratories into larger diagnostic facilities. Nevertheless, the numerous technological advances that emerged at the beginning of the new millennium have helped to create a new testing culture characterized by a countervailing trend of decentralization of some tests closer to patients and caregivers. The forces that have driven this (centripetal) counter-revolution essentially include a few key concepts, namely "home testing", "portable or even wearable devices" and "remote patient monitoring". By their very nature, laboratory medical services and remote patient testing/monitoring are not contradictory, but may well coexist, with the choice of one or the other depending on the demographic and clinical characteristics of the patient, the type of analytical procedure and the logistics and local organization of the care system. Therefore, this article aims to provide a general overview of patient self-testing, with a particular focus on portable and wearable (including implantable) devices.

Comparative effectiveness of warfarin management strategies: a systematic review and network meta-analysis

The management of warfarin therapy presents clinical challenges due to its narrow therapeutic index. We aimed to evaluate the comparative effectiveness of different management strategies in patients using warfarin. PubMed, Embase, Cochrane CENTRAL, CINAHL, and EBSCO Open Dissertation were searched from inception to 8 May 2024. Randomized controlled trials that compared the following interventions: patient self-management (PSM), patient self-testing (PST), anticoagulation management services (AMS), and usual care in patients prescribed warfarin for any indication were included. Risk ratios (RR) with 95% confidence interval (CI) were estimated using a random-effects model. Surface under the cumulative ranking curves (SUCRA) were used to rank different interventions. The certainty of evidence was assessed using the Confidence in Network Meta-Analysis (CINeMA) online platform. This study is registered with PROSPERO (CRD42023491978). Twenty-eight trials involving 8100 participants were included, with follow-up periods of 1-24 months. Mean warfarin dosages were 4.9-7.2mg/day. Only PSM showed a significant reduction of major TE risk compared with usual care (RR=0.41; 95% CI: 0.24, 0.71; I2=0.0%) with moderate certainty of evidence. The 97.6% SUCRA also supported the beneficial effects of PSM over other interventions. The combined direct and indirect evidence showed significantly higher TTR in PSM compared with usual care (MD=7.39; 95% CI: 2.39, 12.39), with very low certainty. However, direct evidence showed non-significant TTR improvement (MD=6.49; 95% CI:-3.09, 16.07, I2=96.1%). No differences across various strategies were observed in all-cause mortality, major bleeding, stroke, transient ischemic attack, and hospitalization. PSM reduces the risk of major TE events compared with usual care, tends to improve anticoagulation control, and should be considered where appropriate. Agency for Healthcare Research and Quality (grant ID 5R18HS027960).

Point-of-care testing, near-patient testing and patient self-testing: warning points.

Point-of-care testing (POCT), near-patient testing (NPT) and patient self-tests (PST) are diagnostic examinations performed at the time and place of patient care. While POCT and NPT are performed and analyzed by medical professionals, PST are based on samples and parameters directly collected and analyzed by lay users. These tests are spreading both in high income countries and in low to middle income countries as they are expected to improve healthcare efficiency and equity, by saving resources, releasing pressure from hospitals and reducing logistical barriers. However, accurate multidisciplinary assessment is mandatory to ensure that what they promise is real. We reviewed some important ethical aspects, international standards and regulations. The current risks associated with alternative ways of testing are explained by the principles of respect for patient autonomy and non-maleficence. Further evidence from multidisciplinary assessment is needed to evaluate pros and cons in light of the principles of beneficence and justice. Although POCT or NPT need common regulation and accurate provider training to ensure safe and appropriate interpretation of results, PST needs even more attention as they are subject to direct patient use. Randomized controlled trails including patient education should be conducted in order to provide reliable evidence on clinical outcomes, patient acceptance and cost-effectiveness. Mandatory regulation is needed to avoid harm and EU regulation should help different countries maintain a safe use of devices in a global population of producers and users.

Outcomes of Warfarin Home INR Monitoring vs Office-Based Monitoring: a Retrospective Claims-Based Analysis

BackgroundHome INR testing (patient self-testing) is feasible and effective for warfarin patients but little is known about real-world differences in outcomes for patients using PST versus laboratory-based INR monitoring.ObjectiveTo compare the safety/efficacy of patient self-testing of real-world warfarin therapy versus office/lab-based monitoring of therapy.Design/Setting/Participants/ExposureA retrospective claims-based analysis of warfarin patients enrolled in the MarketScan® Commercial Claims and Encounters and Medicare databases between January 1, 2013, and March 30, 2020. Stratification was based on INR testing method: patient self-testing versus testing at physicians’ offices/local laboratory. The probability of adverse events in each cohort was determined after adjusting for demographic and baseline clinical characteristics using a repeated measures analysis.Main MeasuresRates of all adverse events: deep venous thrombosis, pulmonary embolism, bleeding, and stroke. A secondary outcome of interest was emergency department visits.Key ResultsA total of 37,837 patients were included in the analysis: 1592 patients in the patient self-testing group and 36,245 in the office-based therapy group. After adjusting for demographic and baseline clinical characteristics, patients in the office-based group had statistically significantly higher rates of all adverse events (incidence rate ratio [IRR]=2.07, 95% CI [1.82, 2.36]), and specific adverse events including thromboembolism (IRR=4.38, 95% CI [3.29, 5.84]), major bleed (IRR=1.45, 95% CI [1.28, 1.64]), and stroke (IRR=1.30, 95% CI [1.05, 1.61]) than patients in the patient self-testing group. Office-based patients also had a statistically significant higher rate of emergency department visits than patient self-testing patients (IRR = 1.65, 95% CI [1.47, 1.84]).Conclusions/RelevanceThis analysis of real-world claims data shows lower rates of stroke, thromboembolism, and major bleeding, as well as fewer emergency department visits, with patient self-testing compared to office-based/lab INR monitoring. Our finding that PST is safe and effective among current users suggests that more patients may benefit from its use.

System Accuracy and Interference Evaluation of a New Glucose Dehydrogenase-Based Blood Glucose Meter for Patient Self-Testing.

New European medical device regulations require the performance of postmarketing surveillance evaluations for blood glucose meters (BGMs). We conducted an ISO15197:2015-conform system performance evaluation with the approved glucose dehydrogenase (GDH)-based Wellion NEWTON BGM. One hundred subjects were enrolled into the study (44 female, 56 male, 43 healthy subjects, 23 type 1 diabetes, 34 type 2 diabetes, age: 53.7 ± 15.8 years). In addition, manipulated heparinized whole blood was used for a laboratory interference test with ten selected substances (interference definition: substance-induced bias > 10%). The mean absolute relative difference (MARD) was 4.7%, and 100% of the values were in zones A (99.7%) and B (0.3%), respectively, of the consensus error grid. Interference was observed with xylose only, which is a known interfering substance for GDH-based BGMs.

Patient Self-Testing of Kidney Function at Home, a Prospective Clinical Feasibility Study in Kidney Transplant Recipients

People with long-term health conditions often attend clinics for kidney function tests. The Self-Testing Own Kidneys (STOK) study assessed feasibility of kidney transplant recipients using hand-held devices to self-test kidney function at home and investigated agreement between home self-test and standard clinic test results. A prospective, observational, single-center, clinical feasibility study (TRN: ISRCTN68116915), with N= 15 stable kidney transplant recipients, investigated blood potassium and creatinine results agreement between index self-tests at home (patient self-testing of capillary blood, using Abbott i-STAT Alinity analyzers [i-STAT]) and reference tests in clinic (staff sampled venous blood, analyzed with laboratory Siemens Advia Chemistry XPT analyzer) using Bland-Altman and error grid analysis. The mean within-patient difference between index and reference test in creatinine was 2.25 μmol/l (95% confidence interval [CI]:-12.13, 16.81 μmol/l) and in potassium was 0.66 mmol/l (95% CI:-1.47, 2.79 mmol/l). All creatinine pairs and 27 of 40 (67.5%) potassium pairs were judged clinically equivalent. Planned follow-up analysis suggests that biochemical variables associated with potassium measurement in capillary blood were predominant sources of paired test result differences. Paired patient and nurse i-STAT capillary blood test potassium results were not statistically significantly different. This small feasibility study observed that training selected patients to competently use hand-held devices to self-test kidney function at home is possible. Self-test creatinine results showed good analytical and clinical agreement with standard clinic test results. Self-test potassium results showed poorer agreement with standard clinic test results; however, patient self-use of i-STATs at home was not a statistically significant source of difference between paired potassium test results.

Clinical Outcomes of Different Warfarin Self-Care Strategies: A Systematic Review and Network Meta-Analysis.

To compare the effects of different strategies for warfarin self-care. PubMed, EMBASE, CENTRAL, CINAHL, ProQuest Dissertations & Theses, and OpenGrey were searched from inception to August 2021. Randomized controlled trials (RCTs) of warfarin self-care, either patient self-testing (PST) or patient self-management (PSM), were included. Self-care approaches were classified based on the TIP framework (theme, intensity, provider): (1) PST ≥1/week via e-Health (PST/High/e-Health); (2) PST ≥1/week by health care practitioner (PST/High/HCP); (3) PST <1/week via e-Health (PST/Low/e-Health); (4) PSM ≥1/week by e-Health (PSM/High/e-Health); (5) PSM ≥1/week by patient (PSM/High/Pt); (6) PSM <1/week by patient (PSM/Low/Pt); and (7) PSM with flexible frequency by patient (PSM/Flex/Pt). Mean differences (MDs) and risk ratios (RRs) with 95% confidence interval (CI) were estimated using frequentist network meta-analyses with a random-effects model. The certainty of evidence was evaluated using CINeMA (Confidence in Network Meta-Analysis). Sixteen RCTs involving 5,895 participants were included. When compared with usual care, time in therapeutic range was higher in PSM/High/Pt and PST/High/e-Health with MD [95% CI] of 7.67% [0.26-15.08] and 5.65% [0.04-11.26], respectively. The certainty of evidence was rated as moderate for these findings. The risk of thromboembolic events was lower in the PSM/Flex/Pt group when compared with PST/High/e-Health (RR: 0.39 [0.20-0.77]) and usual care (RR: 0.38 [0.17-0.88]) with low and very low level of evidence, respectively. There was no significant difference in the proportion of international normalized ratio (INR) values in range, major bleeding, and all-cause mortality among different self-care features. Patient self-care (either PST or PSM) by measuring INR values at least once weekly is more effective in controlling the INR level.

Virtual Education for Patient Self-Testing for Warfarin Therapy Is Effective During the COVID-19 Pandemic.

BackgroundPrior to the COVID-19 pandemic, warfarin users were required to complete in-person training in order to participate in approved international normalized ratio (INR) patient self-testing (PST) programs. To minimize in-person contact during the pandemic, a federal waiver of the in-person training requirement allowed new patients to begin PST after completing virtual training. However, it was uncertain whether such patients achieved comparable levels of INR control to patients receiving in-person training.MethodsINR results for patients receiving virtual training upon PST commencement between April 1, 2020, and December 31, 2020, were compared to those of patients initiating PST with in-person training between April 1, 2019, and December 31, 2019. The primary outcome was the difference in warfarin time in therapeutic range (TTR) between the groups, with secondary outcomes including differences in the percentages of INR values within individually prescribed INR range and of critical INR values.ResultsThe records of 33,683 patients were included in the analysis (13,568 in the “In-Person” sample; 20,115 in the “Virtual” sample). Patients in the Virtual sample achieved a TTR of 66.78%, compared to the In-Person sample (64.19%; absolute difference 2.59; 95% confidence interval [CI] = 2.50–2.68, p < 0.001). The TTR values were also statistically significantly higher in all subgroups evaluated across categories of patient age, gender, geography, and indication. Similarly favorable results were achieved for INR values in range and critical values.ConclusionVirtual education for PST for warfarin therapy is effective and should continue to be an option for patients and providers throughout the pandemic, and possibly beyond.

Hematocrit Self-Testing in Patients with Polycythemia Vera: A Proof-of-Concept Study Assessing the Accuracy of the Statstrip Xpress ® 2 Hb/Hct Device and Its Impact on Patients' Quality of Life in Clinical Practice

Hematocrit Self-Testing in Patients with Polycythemia Vera: A Proof-of-Concept Study Assessing the Accuracy of the Statstrip Xpress ® 2 Hb/Hct Device and Its Impact on Patients' Quality of Life in Clinical Practice

Performance of the microINR Point-of-Care System Used by Self-Testing Patients: A Multicenter Clinical Trial.

Introduction Anticoagulation monitoring is a major practical and clinical challenge. We assessed the performance of the microINR system in patient self-testing (PST). Methods This study was performed at four US medical centers. After the training visit of warfarin anticoagulated patients ( n = 117) on microINR system, PST was performed at home and in two visits to the medical centers. At the medical centers, both PST and healthcare professionals (HCPs) performed duplicate tests with the microINR System. A venous blood sample for the laboratory testing was also extracted. Accuracy and precision were assessed. Results The comparison between microINR PST results and microINR HCP results revealed an equivalence with a slope of 1.00 (95% confidence interval [CI]: 1.00–1.00), and an intercept of 0.00 (95% CI: 0.00–0.00). When compared with the laboratory analyzer, microINR PST results also showed good correlation with a slope of 0.94 (95% CI: 0.86–1.04) and an intercept of 0.14 (95% CI: -0.09–0.34). Predicted bias values at international normalized ratio (INR) 2.0, 3.5, and 4.5 were 0% against HCP and ≤2.5% against the laboratory. Analytical agreement with both HCP and laboratory was 100% according to ISO17593 and 99.1 and 100% according to CLSI POCT14 with HCP and laboratory, respectively. Clinical agreement with HCP regarding 2.0–4.0 as INR therapeutic range was 98% (within range). The precision (coefficient of variation) of microINR system used by PST was comparable to HCP. Conclusion The microINR results when used by self-testing patients show satisfactory concordance to both HCP results and laboratory analyzer. The microINR system is adequate for self-testing use.

Evaluation of the \u201csafe multidisciplinary app-assisted remote patient-self-testing (SMART) model\u201d for warfarin home management during the COVID-19 pandemic: study protocol of a multi-center randomized controlled trial

BackgroundWarfarin treatment requires frequent monitoring of INR (international normalized ratio) to adjust dosage in a therapeutic range. In China, patients living in small towns usually go to tertiary hospitals to get warfarin monitoring and dosing, resulting in low frequencies of follow-ups and high incidence of complications. Influenced by the COVID-19 pandemic, patients on warfarin have further reduced their visits to healthcare institutions. While patient self-testing (PST) via using a point-of-care testing device for INR measuring at home has been widely used in developed countries and demonstrated improved clinical outcomes compared to usual care in clinics, it is rarely applied in developing countries, including China. This proposed study will develop and assess the “Safe Multidisciplinary App-assisted Remote patient-self-Testing (SMART) model” for warfarin home management in China during the COVID-19 pandemic.MethodsThis is a multi-center randomized controlled trial. We will carry out the study in three county hospitals, three small tertiary hospitals and three large tertiary hospitals with anticoagulation clinics in Hunan province of China. Eligible patients will be randomly assigned to the SMART model group (n = 360) or the control group (usual care clinic group, n = 360; anticoagulation clinic group, n = 120). Patients in the SMART model group do PST at home once every two to 4 weeks. Controls receive usual care in the clinics. All the patients will be followed up through outpatient clinics, phone call or online interviews at the 3rd, 6th, 9th and 12th month. The percentage of time in therapeutic range (TTR), incidence of warfarin associated major bleeding and thromboembolic events and costs will be compared between the SMART model group and control groups.DiscussionPatients in the SMART model group would show improved TTR, lower incidence of complications and better quality of life compared to the control groups. Our design, implementation and usage of the SMART model will provide experience and evidence in developing a novel model for chronic disease management to solve the problem of healthcare service maldistribution, an issue particularly obvious in developing countries during the COVID-19 pandemic.Trial registrationChiCTR, ChiCTR 2000038984. Registered 11 October, 2020.

Patient self-testing in chronic disease management

Abstract Chronic disease poses a major burden to patients and health care systems. This review considers how patient self-testing can contribute to the management of chronic disease. Self-testing can only confer benefit if it occurs in the context of an empowered patient who has the skills and training to translate test results into meaningful actions. The benefits may include improved clinical outcomes, greater patient convenience and improved psychological well-being; separately and together these may contribute to reduced costs of care. As self-testing may be expensive and burdensome to patients, it is important that its use in chronic disease is supported by a robust evidence base confirming its utility and efficacy. The design of studies to assess the impact of self-testing poses challenges for the researcher and the quality of evidence presented is often variable. Randomised controlled trials (RCTs) provide more robust evidence than observational studies; the intervention under study is not just self-testing but includes the educational support to allow patients to use results effectively. This review discusses the evidence base relating to patient self-testing in diabetes, anticoagulant monitoring and in renal transplant patients and in particular highlights the impact of new technology developments such as flash glucose monitoring in diabetes.

Patient self-testing of white blood cell count and differentiation: A study of feasibility and measurement performance in a population of Danish cancer patients.

Patients in anticancer treatment with a known side effect of neutropenia are monitored closely with laboratory measurements of white blood cell count (WBC) and differentiation. This study sought to evaluate measurement properties and feasibility of patients' self-testing using a point-of-care testing (POCT) device. A prospective feasibility and measurement study comparing the standard measurement of cancer patients' WBC and neutrophil count with POCT measurements. The study included 60 outpatients and 22 inpatients from a department of oncology at a university hospital. Patients successfully conducted 106 measurements using the POCT device. 46% of the patients were >70years. Weighted Deming regression analysis showed minimal yet significant proportional bias between methods, with POCT increasingly underestimating both total WBC and neutrophils compared with the standard method the higher the count. Over 90% of patients reported they were willing and considered themselves able to use the POCT device at home. The instrument can be used for self-testing of post-anticancer leukopenia and has sufficient measurement precision for patient risk stratification. Patients are able and willing to conduct measurements including when in a situation of acute illness. Further studies are needed to confirm safety and value within patients' own home.

Cost-effectiveness of warfarin care bundles and novel oral anticoagulants for stroke prevention in patients with atrial fibrillation in Thailand

IntroductionNovel oral anticoagulants (NOACs) and warfarin care bundles (e.g. genotyping, patient self-testing or self-management) are alternatives to usual warfarin care for stroke prevention in patients with atrial fibrillation (AF). We aim to evaluate the cost-effectiveness of NOACs and warfarin care bundles in patients with AF in a middle-income country, Thailand. Materials and methodsA Markov model was used to evaluate the economic and treatment outcomes of warfarin care bundles and NOACs compared with usual warfarin care. Cost-effectiveness was assessed from a societal perspective over a lifetime horizon with 3% discount rate in a hypothetical cohort of 65-year-old atrial fibrillation patients. Input parameters were derived from published literature, meta-analysis and local data when available. The outcome measure was incremental cost per quality-adjusted life years (QALY) gained (ICER). ResultsUsing USD5104 as the threshold of willingness-to-pay per QALY, patient's self-management of warfarin was cost-effective when compared to usual warfarin care, with an ICER of USD1395/QALY from societal perspective. All NOACs were not cost-effective in Thailand, with ICER ranging from USD8678 to USD14,247/QALY. When compared to the next most effective intervention, patient's self-testing and genotype-guided warfarin dosing were dominated. In the cost-effectiveness acceptability curve, patient's self-management had the highest probability of being cost-effective in Thailand, approximately 78%. Results were robust over a range of inputs in sensitivity analyses. ConclusionsIn Thailand, NOACs were unlikely to be cost-effective at current prices. Conversely, patient's self-management is a highly cost-effective intervention and may be considered for adoption in developing regions with resource-limited healthcare systems.

Cost-benefit analysis of VKA versus NOAC treatment in German patients with atrial fibrillation utilizing patient self-testing

Background: Clinical complications of long-term anticoagulation in patients with atrial fibrillation cause significant morbidity and have a substantial economic impact on the healthcare system. Objective: To assess the cost-benefit by implementing patient self-testing (PST) in German patients anticoagulated with vitamin K antagonists (VKA) compared to treatment with the new oral anticoagulant drugs (NOAC) apixaban, dabigatran, edoxaban, and rivaroxaban. Methods: A deterministic decision-analytic model was developed simulating the number of major bleedings, ischemic strokes, and hemorrhagic strokes and their associated costs by utilizing PST compared to those of treatment with NOAC. Data on the rates of these adverse events in both groups during the 1st year of treatment was taken from the NOAC approval studies. Direct costs were evaluated from the perspective of the Statutory Health Insurance (SHI) considering the use of resources directly related to PST testing and costs incurred by hospital treatment of the adverse events. Univariate sensitivity analysis was performed to examine the extent to which our calculations were affected by varying the parameters considered in our model within plausible extremes. To capture the interactions between multiple inputs, we also provided a probabilistic sensitivity analysis (PSA). Results: When achieving an average time in therapeutic range (TTR) of 78%, implementing PST in VKA patients reduces cost per patient compared to NOAC treatment between €603.38 [USD 681.52] (edoxaban) and €762.64 [USD 861.40] (rivaroxaban) during the 1-year observation period. In line with the TTR increase, the initially higher number of adverse events per VKA patient compared to NOAC-treated patients in the approval studies becomes largely aligned; the difference in associated hospital costs per patient in the NOAC groups is then only €1.03 [USD 1.16] (in favor of dabigatran), €23.41 [USD 26.44] (in favor of apixaban), €0.53 [USD 0.60] (in favor of edoxaban) and €52.62 [USD 59.43] (in favor of VKA anticoagulation in the rivaroxaban group). In PSA, implementation of self-management results on average in a cost saving between €619.20 [USD 699.39] and €785.24 [USD 886.93] per VKA patient in favor of the SHI. Under all reasonable assumptions, PST remains constantly less expensive irrespective of which NOAC is administered. Conclusion: Implementing PST in German VKA patients may significantly reduce SHI expenditures compared to utilizing NOAC.

The Use of Patient Self-Testing in Low- and Middle-Income Countries

The Use of Patient Self-Testing in Low- and Middle-Income Countries

Home Management of Warfarin Treatment Through a Real-Time Supervised Telemedicine Solution: A Randomized Controlled Trial.

Many patients are undergoing oral anticoagulation treatment with vitamin K antagonists, which necessitates measuring international normalized ratio (INR) several times each month. Patients can learn to measure their INR at home and choose their own dose for the next period with potential gains in treatment quality and reduced healthcare expenses. This is, however, connected to the potential problem of losing tight external control of the patient treatment. We performed a randomized controlled trial using the telemedicine software CSO/AC together with the INR point-of-care-test CoaguChek XS for 10 months to investigate the use of criteria-driven healthcare interactions. A total of 87 patients were divided into two groups. The patient self-management (PSM) group was surveilled using the criteria INR <1.8, INR >4.5, change in warfarin/week >1.25 mg, missing INR or dosage. The patient self-testing (PST) group was handled as routine care. A total of 84 patients were followed for 10 months. No differences were seen in average INR or fraction of INR in therapeutic range (2-3) in the two groups or the start compared with the end. The PST group was handled using 4.2 interactions per month whereas the PSM group used 1.1 interactions per month. No adverse effects of PSM were observed. Using criteria-driven interactions enabled a considerable reduction in interactions per month. The two groups were comparable in terms of treatment effect and safety. Using criteria to guide PSM interactions maintains good treatment effect while reducing healthcare expenses.

Cost-effectiveness analysis of patient self-testing therapy of oral anticoagulation.

Patient Self-testing (PST) could be an option for present anticoagulation therapy monitoring, but current evidence on its cost-effectiveness is limited. This study aims to estimate the cost-effectiveness of PST to other different care approaches for anticoagulation therapy in Thailand, a low-to-middle income country (LMIC). A Markov model was used to compare lifetime costs and quality-adjusted life years (QALYs) accrued to patients receiving warfarin through PST or either anticoagulation clinic (AC) or usual care (UC). The model was populated with relevant information from literature, network meta-analysis, and database analyses. Incremental cost-effectiveness ratios (ICERs) were presented as the year 2015 values. A base-case analysis was performed for patients at age 45-year-old. Sensitivity analyses including one-way and probabilistic sensitivity analyses (PSA) were constructed to determine the robustness of the findings. From societal perspective, PST increased QALY by 0.87 and costs by 112,461 THB compared with UC. Compared with AC, PST increased QALY by 0.161 and costs by 21,019 THB. The ICER with PST was 128,697 (3625 USD) and 130,493 THB (3676 USD) per QALY gained compared with UC and AC, respectively. The probability of PST being cost-effective is 74.1% and 51.9%, compared to UC and AC, respectively, in Thai context. Results were sensitive to the efficacy of PST, age and frequency of hospital visit or self-testing. This analysis suggested that PST is highly cost-effective compared with usual care and less cost-effective against anticoagulation clinic. Patient self-testing strategy appears to be economically valuable to include into healthcare system within the LMIC context.

Clinical evaluation of whole blood prothrombin time (PT) and international normalized ratio (INR) using a Laser Speckle Rheology sensor

Prothrombin time (PT) and the associated international normalized ratio (INR) are routinely tested to assess the risk of bleeding or thrombosis and to monitor response to anticoagulant therapy in patients. To measure PT/INR, conventional coagulation testing (CCT) is performed, which is time-consuming and requires the separation of cellular components from whole blood. Here, we report on a portable and battery-operated optical sensor that can rapidly quantify PT/INR within seconds by measuring alterations in the viscoelastic properties of a drop of whole blood following activation of coagulation with thromboplastin. In this study, PT/INR values were measured in 60 patients using the optical sensor and compared with the corresponding CCT values. Our results report a close correlation and high concordance between PT/INR measured using the two approaches. These findings confirm the accuracy of our optical sensing approach for rapid PT/INR testing in whole blood and highlight the potential for use at the point-of-care or for patient self-testing.

Optical sensing of anticoagulation status: Towards point-of-care coagulation testing.

Anticoagulant overdose is associated with major bleeding complications. Rapid coagulation sensing may ensure safe and accurate anticoagulant dosing and reduce bleeding risk. Here, we report the novel use of Laser Speckle Rheology (LSR) for measuring anticoagulation and haemodilution status in whole blood. In the LSR approach, blood from 12 patients and 4 swine was placed in disposable cartridges and time-varying intensity fluctuations of laser speckle patterns were measured to quantify the viscoelastic modulus during clotting. Coagulation parameters, mainly clotting time, clot progression rate (α-angle) and maximum clot stiffness (MA) were derived from the clot viscoelasticity trace and compared with standard Thromboelastography (TEG). To demonstrate the capability for anticoagulation sensing in patients, blood samples from 12 patients treated with warfarin anticoagulant were analyzed. LSR clotting time correlated with prothrombin and activated partial thromboplastin time (r = 0.57–0.77, p<0.04) and all LSR parameters demonstrated good correlation with TEG (r = 0.61–0.87, p<0.04). To further evaluate the dose-dependent sensitivity of LSR parameters, swine blood was spiked with varying concentrations of heparin, argatroban and rivaroxaban or serially diluted with saline. We observed that anticoagulant treatments prolonged LSR clotting time in a dose-dependent manner that correlated closely with TEG (r = 0.99, p<0.01). LSR angle was unaltered by anticoagulation whereas TEG angle presented dose-dependent diminution likely linked to the mechanical manipulation of the clot. In both LSR and TEG, MA was largely unaffected by anticoagulation, and LSR presented a higher sensitivity to increased haemodilution in comparison to TEG (p<0.01). Our results establish that LSR rapidly and accurately measures the response of various anticoagulants, opening the opportunity for routine anticoagulation monitoring at the point-of-care or for patient self-testing.