Medical devices & diagnostics · Critical care
PreDxion Bio
A University of Michigan spinout that built a thirty minute cytokine test for the intensive care unit, turned it toward COVID-19 in April 2020, then turned again toward consumer home testing. Y Combinator now lists the company as inactive.
The case that started it
In late 2014 a patient at the University of Michigan went into cytokine release syndrome, the immune overreaction that can follow modern cancer immunotherapy. The lab of pediatric critical care physician Timothy Cornell had a research device that could read inflammatory proteins from a single drop of blood in about half an hour. It was not an approved product. Cornell’s lab obtained an emergency use exemption from the FDA to use it on that patient, according to a 2016 account published by Michigan’s biomedical engineering department. The case was a success.
That exemption is the origin story. A graduate student in the lab, Walker McHugh, entered the Michigan Business Challenge to find out whether the device could become a company.
The problem
Patients in intensive care die of immune dysregulation more often than of the infection or injury that put them there. Sepsis, acute respiratory distress syndrome and cytokine release syndrome all involve a flood of signalling proteins, and which proteins are elevated differs from patient to patient. Standard immunoassays take a day or more and run in a central laboratory, which does not help a clinician deciding this afternoon which anti-cytokine drug to give.
MicroKine was a microfluidic nanoplasmonic sensor: localized surface plasmon resonance on a chip, reading six or more cytokines from one drop of serum in under thirty minutes. The sensor work came out of Michigan, with mechanical engineering professor Katsuo Kurabayashi and postdoctoral researcher Pengyu Chen credited as contributors. The NIH project narrative put the promise plainly, a device giving clinicians “serum inflammatory protein levels in less than 30 minutes allowing clinicians to act quickly.”
Two students and a physician
McHugh was a master’s student in Michigan’s Medical Product Development Program. Caroline Landau was an MBA candidate at the Ross School of Business. Cornell was the physician whose lab held the science. They formed the company in 2016 and went onto the business plan competition circuit, which is where the first money came from: a $25,000 Pryor-Hale award and a $5,000 Williamson award at the Michigan Business Challenge, then $100,000 at the Rice Business Plan Competition that April.
In 2017 the company joined Y Combinator’s Summer batch and took the standard accelerator seed. In 2018 the National Institutes of Health added an STTR Phase I award of $224,944 to validate MicroKine in pediatric sepsis, with Cornell as principal investigator. The company moved from Ann Arbor to South San Francisco.
April 2020
On April 24, 2020, Paul Buchheit, the creator of Gmail and a Y Combinator partner, published a post arguing that cheap daily screening could end the pandemic without waiting for a vaccine. He described one technology as the most proven and ready to scale. He did not name the company building it.
Hacker News worked it out within hours. One commenter traced the description to PreDxion and noted the pivot from a hospital setting to a public one. Another asked why the author’s relationship to the company was not disclosed. McHugh answered in the thread himself, which is more than most founders do.
The pivot was real. By that summer the company’s public description was a rapid saliva antigen test for the SARS-CoV-2 spike protein, manufacturable, it said, in tens of millions of units a day using semiconductor fabrication. That description is still the one on the Y Combinator directory page.
What happened next
Not the thing in the description. No PreDxion test appears in the FDA emergency use authorization lists for antigen or molecular SARS-CoV-2 tests, checked again in September 2026. The company registered one clinical study, an observational feasibility study of MicroKine in twenty five critically ill children. It was posted in March 2020, last updated that September while still listed as not yet recruiting, and has carried an unknown status ever since.
By August 2021 the website had changed again. Critical care was gone, COVID was gone, and in their place was consumer home testing. The company later took the name Refractal. Its old domain now serves online casino pages.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| FDA clearance | No 510(k) and no premarket approval under PreDxion Bio or MicroKine in FDA device databases as of Sep 23, 2026. | Public record |
| COVID authorization | PreDxion appears in neither the FDA antigen nor the FDA molecular in vitro diagnostic EUA list for SARS-CoV-2. The saliva antigen test announced in 2020 was never authorized. | Not found |
| Breakthrough Device designation | Claimed on the company site in 2020 and on the Y Combinator page, for the LSPR biosensor in acute respiratory distress syndrome. FDA publishes no list of designations, so it cannot be checked. | Company-stated |
| 2014 emergency use exemption | Reported in March 2016 by the University of Michigan: an FDA emergency use exemption let Cornell’s lab use the device on one patient in cytokine release syndrome. | Institutional |
| Federal grant | NIH STTR Phase I 1R41HD090759-01, $224,944, NICHD, fiscal 2018, principal investigator Timothy T Cornell. No Phase II followed. | Public record |
| Registered study | NCT04295278, observational, 25 patients estimated. First posted Mar 4, 2020. Last update Sep 14, 2020, status not yet recruiting. Overall status unknown. No results. | Public record |
| Peer-reviewed output | One PubMed record carries a PreDxion Bio affiliation: a research letter on endothelial dysfunction markers in pediatric severe sepsis, Feb 2020. No paper describes the saliva antigen test. | Public record |
| Trial sites, as reported in 2018 | A 2018 profile said MicroKine was in clinical trials at UCSF, Mayo Clinic and Mount Sinai. ClinicalTrials.gov holds no PreDxion registration before March 2020, and the one registration names no site. | Differs from registry |
| Securities filings | SEC EDGAR full text search returns no filing mentioning PreDxion or Refractal. No Form D on record. | Public record |
| Operating status | Y Combinator lists the company as Inactive, team size six. The predxionbio.com domain has served gambling pages since 2023; the last company capture is Aug 28, 2021. | Public record |
Read plainly: the science was real and federally funded, and the ICU problem it targeted is real. The product record is thin. One patient used the device under an FDA exemption in 2014, one grant validated the assay, one research letter reached print, and the trial that would have tested the risk model never enrolled anyone. The COVID test that made the company briefly famous produced no authorization, no publication and no product.
What to watch
- Whether the Michigan LSPR sensor line reaches patients through another company. The academic work continued after PreDxion.
- Any Refractal filing or product. Nothing appears in EDGAR under either name.
- NCT04295278. A registration left at unknown status for six years is normally abandoned, not delayed.
- The founders. McHugh later joined Curebase and then SafeBeat Rx as a strategic advisor; Cornell is an endowed professor of pediatric critical care medicine at Stanford.
In their words
“Things haven’t changed much over the last 25 years in terms of how we treat organ failure in the ICU”
Walker McHugh, co-founder, University of Michigan, 2016 · Institutional
“One of the main thrusts of our lab is to develop new diagnostic tools to treat these really sick patients”
Walker McHugh, to Concentrate, April 2016 · Independent
“The $100,000 we are taking home will be allocated to funding manufacturing devices that will revolutionize the way we treat and manage critically ill patients.”
Walker McHugh, TechCentury, April 2016 · Independent
“The team building it originally developed the device to monitor the status of the immune system, but it is easily adapted to detect the proteins on the surface of the virus instead of the proteins used for immune signaling”
Paul Buchheit, investor, A Possible Third Solution to End the Pandemic, April 2020 · Investor
“OK, but what are you detecting? Antibodies? Viral proteins? RNA? The messages from Paul and your team have been contradictory.”
Hacker News commenter, April 2020 · Independent
“There are certainly many hurdles left to be tackled but that’s exactly what we’re working towards.”
Walker McHugh, on Hacker News, April 2020 · Founder
“We are developing beautifully simple home tests that empower people to live healthier, happier lives.”
PreDxion Bio website, August 2021 · Company
Related companies
Sources
- Public recordClinicalTrials.gov NCT04295278, feasibility study of MicroKine Dx system
- Public recordNIH RePORTER award 1R41HD090759-01
- Public recordMarkers of Endothelial Dysfunction and Cytokines in High-Risk Pediatric Patients with Severe Sepsis
- Public recordFDA in vitro diagnostics EUA lists, antigen and molecular SARS-CoV-2 tests
- Public recordBreakthrough Devices Program overview
- Public recordSEC EDGAR full text search for PreDxion and Refractal, no results
- Public recordFederal vendor profile, PREDXION BIO, INC., Dexter, Michigan
- Public recordInternet Archive capture index for predxionbio.com
- InstitutionalBME Students Triumph in Michigan Business Challenge
- IndependentPreDxion Bio’s tech helps tailor treatments to patient’s immune system
- IndependentUM Student Startups Excel At Rice Biz Plan Event
- IndependentUniversity of Michigan student startups win combined $430,000 in Houston competition
- IndependentPreDxion: This Company’s Innovation Could Save Half A Million Lives EVERY Year
- InvestorA Possible Third Solution to End the Pandemic
- IndependentHacker News discussion of A Third Solution, with founder replies
- IndependentRefractal company funding profile, formerly PreDxion Bio
- Public recordNIH STTR award abstract, Validating the MicroKine Assay
- CompanyPreDxion Bio directory entry, Summer 2017, marked Inactive
- CompanyPreDxion Bio website, about text with Breakthrough Device claim
- CompanyPreDxion Bio website, consumer home testing home page
- CompanyWalker McHugh team biography
- Public recordTimothy Thomas Cornell faculty profile
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
