CNSide Diagnostics

What CNSide Diagnostics does

CNSide Diagnostics is a Houston-based molecular diagnostics company operating as a wholly-owned subsidiary of Plus Therapeutics (NASDAQ:PSTV). The company develops and commercializes the CNSide CSF Assay Platform, a proprietary cerebrospinal fluid assay designed to detect, quantify, and molecularly characterize tumor cells in CSF. Its primary clinical application is the diagnosis and monitoring of leptomeningeal metastases, a serious oncology complication involving spread of disease to the membranes surrounding the brain and spinal cord. The customer base comprises neuro-oncologists, oncologists, NCI-designated cancer centers, and academic medical centers, totaling more than 120 institutional accounts.

The platform combines a proprietary multi-antibody microfluidic cell-capture architecture with the CEE-Sure collection and shipping tube, enabling external sites to ship CSF specimens to CNSide's CLIA-accredited, CAP-accredited Houston laboratory for centralized analysis. CNSide has vertically integrated in-house manufacturing of its collection tubes, antibody mixes, and microfluidic chips, which reduces supply risk and tightens control over pre-analytic quality. The business model is fee-for-service clinical laboratory testing, with billing routed through commercial payers, Medicare, and the dedicated CPT code 0640U.

Following a $15M public offering in January 2026, the achievement of CLIA, CAP, and Medicare regulatory milestones, and a national coverage agreement with Elevance Health, CNSide has expanded operations to roughly 48-50 states with payer reach extending to approximately 126 million covered lives. The company is preparing to broaden its menu with CSF-based ICC, FISH, and NGS assays in 2026 and has signaled intent to expand internationally after U.S. scale is established.

Name

CNSide Diagnostics

Legal name

CNSide Diagnostics, LLC

Website

https://cnside-dx.com

Company type

Private

Founded year

2024

Operating status

Operating

Headcount range

11–50 employees

Short description

CNSide Diagnostics, a Houston-based subsidiary of Plus Therapeutics, operates a CLIA-accredited molecular diagnostics laboratory running the proprietary CNSide CSF Assay Platform to detect and characterize tumor cells in cerebrospinal fluid for neuro-oncologists managing leptomeningeal metastases.

Ownership category

akta.pro rank

Product category

Molecular Diagnostics

NAICS

Medical Laboratories (621511), In-Vitro Diagnostic Substance Manufacturing (325413), Medical and Diagnostic Laboratories (62151)

SIC

Services-Medical Laboratories (8071), In Vitro & In Vivo Diagnostic Substances (2835)

akta.pro primary industry

Oncology Diagnostics (tumor profiling, MRD, liquid biopsy) (HLAAALAE)

akta.pro secondary industries

Cytology & Histopathology Diagnostics (IHC, ISH, tissue-based assays) (HLAAALAI), Specialty & Biomarker Laboratory Services (Immunoassays/Flow/Cytometry) (HLAGAEAB)

Keywords

• Liquid biopsy diagnostics
• Cerebrospinal fluid testing
• Leptomeningeal metastases detection
• Molecular cancer diagnostics
• Tumor cell enumeration

Headquarters

HQ city

Houston

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Technology or R&D, Operations, Marketing or Sales, Infrastructure

Revenue model

1. Laboratory Testing Services: CNSide Diagnostics generates revenue through clinical laboratory testing services. The company bills commercial payers, Medicare, and patients for its CSF tumor cell enumeration test. A new CPT code (0640U) became effective July 1, 2026, enabling standardized billing and claims processing.
2. Commercial Payer Agreements: Revenue generated through coverage agreements with commercial health insurers including United Healthcare, Humana, Highmark, Blue Shield of California, and Elevance Health. The company has approximately 126 million total contracted covered lives as of June 2026.

Pricing tiers

Go-to-market motion2 records

Distribution channels1 record

Marketing channels6 records

Core offering

CNSide Diagnostics operates a CLIA-certified clinical laboratory that runs the proprietary CNSide® CSF Assay Platform, with the commercially available CNSide® CSF Tumor Cell Enumeration (TCE) test detecting and quantifying tumor cells in cerebrospinal fluid for diagnosing and monitoring leptomeningeal metastases. The company also manufactures the proprietary CEE-Sure® CSF Collection Tube preservative used to stabilize CSF specimens during transport, and is developing molecular characterization tests (ICC, FISH, NGS) on the same CSF sample.

Product overview

CNSide Diagnostics offers the CNSide® Cerebrospinal Fluid (CSF) Assay Platform, a suite of molecular diagnostic tests for detecting and analyzing cancer cells in cerebrospinal fluid. The platform currently includes the commercially available CNSide® CSF Tumor Cell Enumeration (TCE) test, with additional tests in development including CSF ICC, FISH, and NGS tests expected to launch in 2026. The company manufactures key test components including the CEE-Sure® CSF collection tube preservative, antibody mix, and microfluidic chip in-house at its Houston, Texas facility for vertical integration and scalability. The platform enables rapid diagnosis, treatment monitoring, and treatment guidance for patients with leptomeningeal metastases.

Differentiator

Problem solved

Functional benefit

Brands

• CNSide® CSF Assay Platform: A proprietary cerebrospinal fluid assay platform that provides tumor cell enumeration and molecular characterization for managing leptomeningeal metastases and CNS cancers.
• CNSide® CSF Tumor Cell Enumeration (TCE)

Products and services

• CNSide CSF Tumor Cell Enumeration (TCE) Test Clinical laboratory test that detects, quantifies, and reports tumor cells in cerebrospinal fluid using the proprietary CNSide CSF Assay Platform; intended for neuro-oncologists and oncologists diagnosing and monitoring leptomeningeal metastases from solid tumors.
• CEE-Sure CSF Collection Tube Proprietary specimen collection tube containing a preservative that stabilizes cerebrospinal fluid during transport to the CNSide Diagnostics CLIA laboratory, supporting the integrity of the Tumor Cell Enumeration test.

Quantifiable outcome

• 92% sensitivity and 95% specificity for leptomeningeal metastases detection
• +3 more outcomes

Named customers2 records

Segments3 records

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

One partnership is on record.

• Plus Therapeutics, Inc.coreOthersCNSide Diagnostics, LLC is a wholly-owned subsidiary of Plus Therapeutics, Inc. (NASDAQ: PSTV). Plus Therapeutics acquired all CNSide® assets and established CNSide Diagnostics in 2024. The subsidiary operates independently to commercialize the CNSide CSF Assay Platform while Plus Therapeutics focuses on its radiopharmaceutical pipeline including REYOBIQ.

Scale indicators7 records

Recent moves8 records

Expansion highlights6 records

Direct peers

• Guardant Health: Leading oncology liquid biopsy company with Guardant360 CDx and Guardant Reveal MRD products using cell-free DNA approaches. Most directly comparable peer in the blood-based oncology liquid biopsy category, sharing CNSide's strategy of using rare-cell/DNA analytics to guide solid tumor treatment.
• Personalis: Molecular diagnostics company offering NeXT Personal (tumor-informed MRD) for solid tumors. Direct peer in liquid biopsy MRD and treatment monitoring for oncology, with similar payer coverage focus.
• Biocept: Originally developed and commercialized the CNSide® CSF assay platform beginning in 2020; CNSide Diagnostics was established in 2024 when Plus Therapeutics acquired all CNSide assets from the prior program. Biocept represents the most direct historical predecessor in CSF-based liquid biopsy for oncology.
• Natera: Oncology liquid biopsy peer commercializing Signatera for molecular residual disease (MRD) monitoring and treatment response assessment. Shares CNSide's molecular treatment-monitoring positioning and similar payer-coverage expansion strategy across U.S. oncology.
• Tempus AI: AI-powered precision medicine company offering xT (tissue), xR (liquid biopsy/RNA), and xF (ctDNA) oncology diagnostics. Comparable peer combining molecular profiling with proprietary data/molecular tumor board workflows for academic oncology centers.
• Foundation Medicine: Subsidiary of Roche providing comprehensive genomic profiling (FoundationOne CDx) and liquid biopsy (FoundationOne Liquid CDx) for solid tumors. A direct molecular tumor profiling and liquid biopsy peer with overlapping clinical customers (academic medical centers, oncologists).
• Caris Life Sciences: Molecular profiling company offering MI Profile (tissue) and MI Cancer Seek (blood) for solid tumor molecular characterization and MRD. Directly comparable on molecular tumor profiling and CNS-adjacent cancer applications.
• NeoGenomics: Oncology-focused clinical laboratory and molecular diagnostics company offering comprehensive tumor profiling, including liquid biopsy services. Closely comparable specialty lab operating model with similar payer coverage and academic cancer center customer focus.

Broad incumbents

• Exact Sciences: Larger oncology diagnostics incumbent with Cologuard (screening) and Oncotype DX (tumor profiling), now expanding into MRD via the Thrive acquisition. Comparable on payer contracting scale and commercial U.S. footprint but broader, more diversified than CNSide's leptomeningeal focus.

Emerging players

• Burning Rock Biotech: China-based oncology liquid biopsy company commercializing tumor profiling and MRD assays. Comparable technology and clinical positioning with CNSide, but operating from a different geography and primarily serving the Chinese market.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xx.com/cnsidedx
• YouTubeyoutube.com/@cnsidediagnostics/videos
• Facebookfacebook.com/cnsidediagnostics
• LinkedInlinkedin.com/company/cnsidediagnostics
• Instagraminstagram.com/cnsidediagnostics

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles10 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about CNSide Diagnostics