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ARCHIMED Diagnostics closes its acquisition of ARK Diagnostics
October
28,
2025
ARCHIMED Diagnostics – the Diagnostics team of global private equity healthcare specialist ARCHIMED – has closed its carve-out of Fremont, California-based ARK Diagnostics from listed South Korean specialty chemical company, Soulbrain Holdings (KRX: 036830). ARCHIMED Diagnostics identifies diagnostics investments for all ARCHIMED funds. ARK is ARCHIMED Diagnostics’ third investment in 2025.
The 60 percent of ARK acquired by ARCHIMED Diagnostics is held through ARCHIMED’s MED Platform II fund. Soulbrain reinvested a substantial proportion of its proceeds from the deal in a new 40 percent stake in ARK. The transaction gives ARK an enterprise value of $428 million.
ARK is a global leader in the development and manufacture of specialty immunoassay In Vitro Diagnostics, with a focus on Therapeutic Drug Monitoring (ensuring the amount of drugs taken by patients is safe and effective), and Drugs of Abuse testing for human and veterinary applications.
Founded in 2003 and acquired by Soulbrain in 2018, ARK is noted for its advanced Enzyme-Multiplied Immunoassay Technique. EMIT is an immunological diagnostic method used for measuring a wide range of small molecules. It offers an especially fast, automated, and particularly sensitive means of detecting drugs and other substances.
ARK has a diversified portfolio of products and patents, with over 30 proprietary assays, or tests, that are sold in over 30 countries. These leading-edge assays cover critical disease areas such as epilepsy, cancer, autoimmune disorders, and kidney diseases, solidifying the company’s position as a market leader.
Operating in Specialty Immunoassays, a priority investment area for ARCHIMED, ARK was identified and prioritized by ARCHIMED Diagnostics as a category leader through ARCHIMED’s MedDiscover approach. MedDiscover is a set of tools, processes, and systems permitting ARCHIMED to identify and effectively negotiate with leading companies in prioritized subsectors.
ARK, Soulbrain and ARCHIMED started their relationship in 2018 through collaboration with EUROlyser, an ARK client, sold by ARCHIMED in 2022 for a 6x return (EUROlyser is a point-of-care testing specialist, where testing is done at the time of consultation, leading to immediate availability of results). The arrival of ARCHIMED in Asia in January, 2024, where the group opened offices in Japan and South Korea, spurred a deeper partnership.
As part of the transaction, ARCHIMED and Soulbrain have signed a joint venture agreement that will accelerate ARK’s development of new technologies, new products and global reach. “Combining forces with Soulbrain and working with existing management is a recipe for super-charging ARK’s impressive growth,” says ARCHIMED’s Tokyo-based managing partner, Vincent Guillaumot. “All of us, Ark, Soulbrain and ARCHIMED, are very comfortable working together after EUROlyser’s success.”
To compliment ARK’s already impressive sector expertise, innovation talent, international access, US-Asia collaboration, and navigation of diverse regulatory regimes, ARK is being reinforced with appointments from ARCHIMED’s MedTalents®. This is a network of ARCHIMED-associated senior healthcare executives who identify, facilitate and advise on deals and counsel ARCHIMED partners. Michael Gruber, a serial entrepreneur in IVD joins as Chief Commercial Officer, while former IVD industry CEOs Douglas Bryant (from QuidelOrtho), and Roland Diggelmann (from Roche Diagnostics) join the board.
ARK is the fourth transaction – and second joint venture – of ARCHIMED in Asia, following the purchases of Nihon Koden-Ad-Tech Medical and Jeisys Medical, and strategic investment in Agatha Inc.
“All of us, Ark, Soulbrain and ARCHIMED, are very comfortable working together after EUROlyser’s success.”
Vincent Guillaumot, Managing Partner at ARCHIMED
ARK is MED Platform II’s ninth investment. All of MED Platform II’s investments have been first-time leveraged buyouts for the companies acquired. MED Platform II closed on €3.5 billion in June, 2023.
Soulbrain Holdings is a diversified and fast-growing chemical conglomerate headquartered in South Korea. Its main subsidiary, Soulbrain is noted for technologically advanced specialty chemicals used in the production of semiconductors and other products. Soulbrain is developing its bio-healthcare division.