25 Oct. 2021 – Once valued at more than $ 9 billion dollars, it looks like Theranos will change the world of routine blood test. Their claim was revolutionary: Using blood from a finger prick, they were able to perform more than 200 different tests. With a trip to a local pharmacy, someone can have tests done without drawing blood and receive the results in hours rather than days. What’s more, Theranos said that dozens of tests can be performed on one drop of blood alone, and these tests will cost a fraction of traditional laboratory work.
But known, Theranos’ house of cards collapsed. The microwave-sized machine that was supposed to perform these tests, called the “Edison,” simply did not work. What came as a shock to Silicon Valley and the investment world came as no surprise to those in the blood testing industry.
“It was like saying you can build a flying car that is also a submarine, for the same price as an entry-level Toyota,” says Sheldon Campbell, MD, PhD, a professor of laboratory medicine at the Yale School of Medicine.
Unlike the world of computer technology, where one breakthrough can revolutionize the entire field, advances in blood analysis are more steady and slower, like the automotive industry, Campbell says. While the automotive industry developed hybrids and electric vehicles, the foundations of a car remained the same.
“The driving lanes have not changed, and the tires have not changed,” he says. “It’s pretty mature technology.”
Similarly, the process in blood testing is evolutionary, rather than revolutionary.
When you have blood tests done, the technician uses a needle to draw blood from a vein in your arm into a blood collection tube. Each tube collects between 1/2 to 1 teaspoon of blood, and the technician will fill one to several tubes during the draw, depending on the number of tests your doctor has ordered. This gives laboratory technicians enough to work with, and doctors can even request additional tests after a sample has been taken.
About half of blood consists of red and white blood cells, while the other half is fluid. Most diagnostic tests use the liquid portion, which means that only half of a standard sample is usually used for testing. You can also use blood from a finger prick, also known as a capillary sample, for testing, but it can be more difficult. These samples – a few drops of blood – are 30 to 100 times smaller than your standard blood draw. Unlike blood taken directly from a vein, capillary blood is mixed with fluid from tissues, which can contribute to an inaccurate result.
For simpler tests such as checking glucose levels, something people use diabetes do several times a day, using a small amount of blood from a finger works just fine. In fact, even the most advanced glucose monitors can produce accurate results with a fraction of the blood needed for a typical capillary sample.
“You can literally take the capillary sample, place it on your test strip, put it in your device, and this simple one-step chemical reaction takes place in that test chamber so you can get a glucose measurement,” says Kimberly Sanford, MD, president of the American Society for Clinical Pathology.
But moving more complex tests that require multiple chemical reactions from central laboratories and to clinics is becoming more difficult, Sanford says. Performing multiple tests on a few drops of blood also adds additional engineering challenges, as a certain amount of blood is required for each result.
Diagnostic tests performed outside the laboratory, also known as point-of-care testing, are also more expensive than tests performed in a centralized laboratory. While these larger laboratories are built to manage multiple samples at a time, point-of-care testing is done one at a time.
To really get your money’s worth, the tests need to be easy, fast and, above all, accurate. Unless these in-office tests can provide clinicians with all the information they need to make a medical decision, it makes more sense to send samples to a lab.
“No point of care testing, no matter how simple, is easier than ticking another box on a lab order form,” Campbell says.
But despite these obstacles, pieces of laboratory testing have made their way to clinics and bed care.
“They are similar technologies to what we would use in the main laboratory on the larger analysts, but they miniaturize them to make them more portable,” says James H. Nichols, PhD, a professor of pathology, microbiology and immunology at the Vanderbilt University Medical Center in Nashville.
Advances in microfluidics – systems that process very small amounts of fluid for testing – have made it possible to perform multiple diagnostic tests on a few drops of blood, just not as much as Theranos promised.
Abbott Laboratory’s i-STAT, for example, a portable blood analyzer with test-specific, one-time cartridges, can deliver multiple results from a standard fingerprint sample. They Chem 8+ pattern can yield results for nine metabolic measures with a few drops of blood. To perform a test, the user places two or three drops of whole blood on the test pattern, which is then placed in the analyzer. A new test pattern is used for each patient.
The i-STAT delivers laboratory-accurate testing for blood gases, electrolyte, chemistry, coagulation, hematology, glucose and heart markers, says an Abbott spokesman. Results are available within 2 minutes.
While the device was designed for urgent care settings, it is now also used at health shows, medical tents at events and many other mobile care settings, says Nichols.
A few tabletop blood chemistry analysts who perform the same type of tests are also available for both emergency care as well as outpatient clinics. The Klein Xpress, for example, a portable analyzer that is about the size of a shoebox can perform up to 14 tests on a finger prick blood sample and produce results in 12 minutes.
Complete blood counts, a common group of tests that count the number of white blood cells, red blood cells and platelets in your blood, have also begun to make their way to primary care and other outpatient clinics, Nichols says. With a few drops of blood, a clinic can get results in 3 minutes or less.
We look forward to, “there will also be more infectious diseases [testing] moving from the main laboratory to the community, ”says Nichols, driven in part by the importance of rapid COVID-19 testing. For example, the development of additional rapid, easy-to-use tests for diseases that are more common outside the United States, such as malaria and knokkelkoers, can help improve access to laboratory diagnostics in developing countries, he says.
“It’s going to be an evolutionary process,” Campbell says, as bits and pieces of laboratory testing continue to be adapted for faster and more portable technologies. “And it will work for both directions. The point-of-care market is clearly expanding, and people are coming up with clever ideas and ways of doing things at point-of-care, but the laboratory-based side will also not be static, ”he said. he said. “They will kind of grow towards each other.”