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Can You Really Test for Diseases on a Single Drop of Blood?

blood droplet

Can You Really Test for Diseases on a Single Drop of Blood?

The futuristic concept of testing for a variety of inconsistencies in blood with just a drop seemed within reach with the promising company Theranos. The company assured investors and the public that they had the capacity and were close to technology that could test a panel of 100 markers with just a drop of blood; a huge scientific advancement from where the blood testing industry currently stands. But Theranos didn’t deliver. That raises the question of whether anyone can.

The story of Theranos

Blood-testing startup Theranos has become a cautionary scientific tale. The name is now synonymous with underdelivering and possibly defrauding investors and the public.

After massive rounds of fundraising in 2013 and 2014, in 2015, The Wall Street Journal raised a red flag on some of Theranos’ technology and from there the problems snowballed for the tech company. In 2016, the Journal of Clinical Investigation found that Theranos flagged tests 1.6 times more often than other testing services because of inconsistencies that influenced lab results. The company dissolved in September of 2018 after facing years of questions and concerns regarding the technology and feasibility of being able to test a slate of 100 markers off of a single drop of blood.

The issues and challenges of the technology

Theranos was up against major challenges when it came to technology, which is why you haven’t heard of many other major challengers in the field. They are out there, but there is still research and testing to be done and most of them still don’t make the promises that Theranos did.

Generally, laboratory draws take about 6 ML of blood from the veins, but do not require nearly that much for each of the tests run. If you could run a test with less blood  — and less invasively — wouldn’t that be better? Many patients and health professionals would certainly think so. So why can’t we test diseases on a fingertip yet?

In a blood sample as small as the one that comes from a finger prick, there is high variability in many markers. One marker with high variation is hemoglobin. Another is white blood cell count. Taking the blood from the capillary level stabilizes most of these variabilities, which is why that method is most common.

Another challenge in developing this technology is that there’s also more than just blood in that finger-stick sample. Ruptured cells can leak into the collected blood and fluid from in between cells also gets in. Any variation in the blood gets magnified in these tiny sample sizes and will send back incorrect test results.

Who is still out there?

So if there are many barriers to this technology, why are people still trying to improve it? Why is this important?

These finger-prick samples would be beneficial for the most vulnerable of patients, like newborns and cancer patients, who can’t undergo large blood draws. It would also eliminate the concern of adding anemia problems to already sick patients and make these tests highly portable for hospital use. The development is definitely a challenge, but a blood test that requires just a drop would be a valuable addition to medical technology. That’s why while Theranos was the most infamous, it was never the only horse in this race. Many companies are close to achieving products that work for these purposes. Here are several that are making strides.

Micro Blood Science Inc.

This Japanese company has developed a system that tests for 14 markers and is currently in use in Japan. It uses just a few drops of blood from the fingertip. They have been able to achieve a high-level of accuracy when comparing them to blood draws taking in veins.


The iStat is a handheld blood analyzer that uses two to three drops of blood and returns results in about two minutes. It offers a range of testing cartridges including sodium, potassium, glucose, and hemoglobin. Cartridges can run over 10 tests simultaneously.

Seventh Sense Biosystems

Seventh Sense Biosystems’ Tap device avoids the normal pitfalls of a finger-prick test because it doesn’t perform a finger-prick device. The FDA-approved device collects capillary blood from the upper arm with a series of microneedles and vacuums.The process takes two to three minutes, but is much less invasive and takes a smaller amount of blood than a normal blood draw. While the slate of tests that can be run with Tap is still small, it is believed to have much wider implications for the future of blood testing and at home sample collection.


Startup Genalyte’s Maverick testing system can run up to 62 different tests on a single drop of blood. The results from Maverick are available in 10 to 30 minutes depending on the type of tests performed. FDA approval was still pending.

Athelas Inc

Athelas is a California-based company. According to Athleas, “our proprietary test strip generates immune and hematological indices from a drop of blood in seconds.” It’s currently undergoing FDA review.

1Drop Diagnostics

The chips are what make 1Drop Diagnostics different. According to the company, they “miniaturize biochemical reactions preserving valuable samples and reagents, increasing the sensitivity of tests, accelerating mass transport limited reactions, leading to a faster time to high quality results.” It requires only one drop of blood for a complete diagnostic test. The company is based in Boston, Massachusetts and Neuchatel, Switzerland and recently raised over $4 million in funding.


Sight has developed complete blood count testing in the form of their machine, OLO. Meant to be used in doctor’s offices, it takes just two drops of blood. It also utilizes artificial intelligence.


The fight to use micro-amounts of blood to run full slates of tests is far from over. The gains that could be made with this kind of technology make the challenges worth tackling for many companies, and many are working to solve the blood-testing issue. Theranos may have been a let-down, but the development of blood-testing technology is still a scientific question worth answering.