Karius is a life sciences company specializing in advanced metagenomic diagnostics to detect pathogens and improve infectious disease care, particularly for immunocompromised patients.
Last year, you described 2025 as a transformative year for Karius, with rapid growth and expansion. At the time, your Karius Spectrum test was in use at more than 400 U.S. hospitals. To what extent has that expansion materialised, and is that number any higher today?
Yes. From a business standpoint, that number could easily climb to 600 hospitals by the end of this year. Thousands—and soon tens of thousands—of clinicians have used our test in hospitals across the U.S. What’s remarkable is how many different specialists now rely on it: not just infectious disease experts, but also cardiologists, oncologists, pulmonologists, and haematologists treating immunocompromised patients.
We are very deliberate about responsible adoption. We don’t promote our test for every hospital admission; instead, we focus on the sickest patients with the highest risk of death. That approach has been central to our mission. Importantly, we are now included in six medical professional society guidelines—covering solid organ transplant, endocarditis, stem cell therapy, HIV, and neutropenic cancer patients—recognising our technology as part of the U.S. standard of care.
Do you have statistics on how many lives have been saved or extended with your test’s help?
We’ve tested over 100,000 immunocompromised patients in hospitals—an extraordinary contribution for a company of 200 people and a new genomic technology in infectious disease. This is the first time genomics has reached the hospital setting at this scale. In 2025, we also launched a second test, Karius Focus,—a bronchial alveolar lavage (BAL) test—used to diagnose pneumonia by analysing fluid samples from the lungs.
There are about 700,000 such bronchoscopies performed yearly in the U.S., and our new test can detect 50% more causes of disease within one day of receiving a sample. Adoption has been remarkable: within five months, over 100 hospitals began using it, reaching the same adoption level our first test achieved in its third year.
Can you explain in more detail the difference between the Spectrum and Focus BAL tests?
The Spectrum test uses a blood sample to find DNA fragments from the organisms causing infection. Through DNA sequencing, it can identify around 1,400 organisms. The Focus BAL test, by contrast, analyses fluid from the lungs and identifies close to 600 pathogens.
Sometimes, the BAL test detects infections that Spectrum might not catch, but ideally, Spectrum should be used on day one of hospital admission. It can often eliminate the need for an invasive bronchoscopy altogether. Still, for patients who go directly to bronchoscopy, the Focus BAL test ensures we can support them wherever they are in their care journey.
Has the conversation around cost–benefit shifted over the past year? Is it now easier to engage hospitals about introducing your technology?
Yes, it has. Adoption itself is the strongest evidence—hundreds of new hospitals and thousands of new doctors are now using our test. While many U.S. hospitals face financial strain, large cancer centres and transplant institutions are well positioned to adopt our technology. Each order of our $2,000 test represents a conscious vote of confidence—clinicians pay directly for a tool they believe will change patient outcomes.
Every time a hospital orders our test, it makes both a clinical and financial decision, which speaks volumes about its perceived value. This balance between clinical need and financial judgment is, in many ways, a fascinating American healthcare experiment.
How do you see affordability and access evolving in the future?
In most cases, our $2,000 test is a fraction of the cost of hospitalisation, which can easily reach eight to ten times that amount in just the first week of a 19-day stay. In such life-threatening situations, the value of our test isn’t even a question. Over time, genomic technology continues to become more affordable and accessible, and we expect this test to follow the same trajectory. Eventually, patients will be able to use it on an outpatient basis, even from home, if they develop a fever. In those cases, insurance companies will cover it, making it a modest part of the overall cost of managing serious conditions like cancer or organ transplant recovery.
AI is now central to life sciences innovation. How does Karius use it to enhance testing?
Machine learning and large language models have been part of our platform since its inception a decade ago. Each test generates millions of DNA sequencing reads, and AI is essential for sorting and analysing this data. We regularly update our bioinformatics pipeline to improve accuracy and performance.
Looking forward, AI will power two major areas: leveraging hospital and patient data to provide richer diagnostic insights, and enabling clinical decision support. Physicians today are overwhelmed by data—lab results, imaging, consult notes—and AI can help synthesise that information. Our goal is to give doctors clear, actionable answers to the most critical question: “What should I do next?”
How would you characterise the new administration’s stance toward the life sciences industry?
Any change in administration presents challenges for U.S. healthcare, whether in funding or evidence-based policy. But across parties, there’s universal agreement that America must lead in medical and scientific innovation. Our nation’s strength lies in ensuring that people with cancer, HIV, autoimmune disease, or transplant needs have access to life-saving breakthroughs.
Roughly 7% of Americans—about 20 million people—are immunocompromised, unable to fight infections like healthy individuals. Everyone has been touched by such illness, whether through family or friends. That shared experience creates broad bipartisan understanding of the urgency to protect these patients.
Finally, where would you like to see Karius a year from now?
Our top priority is access—making sure more doctors, hospitals, and patients benefit from our test. We already have over 300 peer-reviewed publications demonstrating superior outcomes versus standard care, which has earned us inclusion in six medical guidelines. But we must continue raising awareness and providing evidence to expand access further.
Every two minutes, an immunocompromised patient—often a cancer patient—dies from infection. Around 20 people have died since we began this conversation. Our mission is to reduce that number by ensuring hospitals have the tools and knowledge they need.
Inclusion in professional guidelines also signals that our test is both clinically effective and economically viable—part of modern best practice.
