June 28, 2022

Researchers utilized a smartphone app to develop a novel blood-clotting test that is both affordable and accessible to millions of people across the world

Bleeding disorders are a group of conditions characterized by an inability to create a proper blood clot. Excessive bleeding after an accident, surgery, trauma, or menstruation is one of the symptoms. Sometimes the bleeding is uncontrollable and has no recognized or recognizable source. Defects in blood components such as platelets and/or clotting proteins, also known as clotting factors, can cause improper clotting. Hemophilia and other bleeding diseases can be inherited or acquired. Other causes include anemia, cirrhosis of the liver, HIV, leukemia, and vitamin K deficiency. They can also be caused by blood-thinning drugs such as aspirin, heparin, and warfarin. Hemophilia A and B, as well as von Willebrand disease, are the most frequent forms of bleeding disorders.

Number of people diagnosed with Hemophilia and Willebrand disease globally

Source: www.statista.com

The human body responds to injury by causing bleeding, which is then followed by clot formation and, finally, lysis. This meticulously maintained balance reduces the risks of bleeding and abnormal clotting, such as ischemic stroke, myocardial infarction, or pulmonary embolus. Medical diseases such as atrial fibrillation, artificial heart valves, and genetic mutations, on the other hand, raise the risk of morbidity and mortality from blood clotting for millions of people. These people must take anticoagulants like warfarin for the rest of their lives. Warfarin is an effective treatment, but it is also one of the most common reasons for hospitalization caused by adverse drug reactions. Due to the drug’s limited therapeutic index and interactions with food and other drugs, its effect must be continuously monitored by regular prothrombin time (PT) or international normalized ratio (INR) tests to measure coagulation characteristics. Despite the growing popularity of novel anticoagulants that do not require regular PT/INR monitoring, research show that warfarin is still the most widely given outpatient blood thinner. However, warfarin is really not ideal, and patients must be checked periodically to ensure that their blood is in the proper range; blood that clots too rapidly can still lead to a stroke or heart attack, while blood that does not clot might result in prolonged bleeding after an accident. Patients must either visit a clinic laboratory or utilize a pricey at-home testing method to get tested.

A novel blood-clotting test created by University of Washington researchers employs only a single drop of blood and a smartphone vibration motor and camera. A plastic attachment holds a little cup beneath the phone’s camera as part of the system. A drop of blood is placed in the cup, which contains a tiny copper particle as well as a chemical that initiates the clotting process. The phone’s vibration motor then shakes the cup as the camera tracks the particle’s progress, which slows and ultimately stops when the clot develops. The researchers demonstrated that this procedure is within the accuracy range of the field’s standard equipment.

The findings were published in Nature Communications on February 11th, which showed that doctors used to physically bounce blood tubes back and forth to see how long it took for a clot to develop back in the day. This, however, necessitates a large amount of blood, making it unsuitable for usage in the house. The creative leap made here shows that the algorithms can perform the same thing as a single drop of blood by utilizing the vibration motor on a smartphone. And they achieve accuracy that is comparable to the best commercially available methods. Despite the availability of various home PT/INR testing modules, finding a cost-effective and reliable PT/INR test remains a barrier. In the United States, patients are only in the therapeutic range around 64% of the time. Patients in underdeveloped nations such as Botswana, Uganda, and India fall into this category just 40% of the time due to fewer tests. Despite the potential benefits of home PT/INR testing, these devices are expensive, limiting their value in resource-constrained regions.

The researchers wanted a low-cost gadget that could function similarly to at-home blood sugar monitors for diabetics: A person can test a drop of blood by pricking their finger. They began by vibrating a single drop of blood and attempting to observe waves on the surface, but this proved difficult due to the little amount of blood obtained. Since the motion of a little copper particle was so much easier to track, the team decided to include it. As the blood clots, it produces a tightening network. The particle moves from merrily bouncing about to no longer moving as a result of this process. The phone captures two-time stamps to determine PT and INR: the first when the user adds the blood and the second when the particle stops moving. They were looking for the first-time stamp when the user inserted a capillary tube with the sample into the frame. They gaze straight at the interior of the cup towards the conclusion of the measurement, so the copper particle is the only movement within those frames. Because blood clots fast, the particle abruptly stops traveling, and we can see the difference between frames. We may then compute the PT, which can then be converted to INR.

This approach was tested on three distinct types of blood samples by the researchers. The researchers began with plasma as a proof of concept since it is a transparent component of blood that is easy to test. At the University of Washington Medical Center, the researchers examined plasma from 140 anonymous individuals. The researchers also looked at plasma from 79 patients who had previously been diagnosed with blood clotting problems. The test produced findings that were comparable to commercially available assays for both of these diseases. The scientists next analyzed whole blood from 80 anonymized individuals at both Harborview and the University of Washington medical institutions to simulate what a patient might experience at home. The findings of this test were largely within the accuracy range of commercial testing.

The proof-of-concept stage of this gadget is currently ongoing. The code has been made available, and the researchers are looking at commercialization and further testing options. For example, all of these tests are now carried out in a laboratory. Working with patients to test this system at home is the next step. The researchers also want to explore how the system is functioning in locations and nations with fewer resources. A vibration motor and a camera are found in almost every smartphone released in the last decade. As a result, practically everyone with a phone can utilize it. The only requirement is a basic plastic attachment and no additional electronics. This is essentially the holy grail of PT/INR testing, as it combines the best of all worlds. It makes it cost-effective and accessible to millions of people, even in areas where resources are scarce.


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