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You can patent a diagnostic method in the United States, but only if the method goes beyond simply observing a natural correlation. To qualify, the innovation must apply that correlation through defined steps that produce a measurable and practical outcome. The key is whether the diagnostic process adds a human-driven, technical contribution rather than relying on a law of nature alone. This blog explains how patent eligibility works, how courts evaluate diagnostic claims, and what biotech teams should consider before filing.
Patent Eligibility: How Diagnostic Methods Are Evaluated
Courts have made diagnostic method claims more complex to protect, especially after Mayo v. Prometheus and related decisions. The current framework asks whether the method applies a natural relationship in a meaningful, concrete way.
Patent examiners typically look for:
- More than detection of a naturally occurring marker
- A step that transforms or manipulates materials or data
- A practical application with measurable results
- A process that could not be performed mentally
When a diagnostic method includes identifiable technical actions, it is more likely to survive eligibility review.
What Courts Consider a “Natural Law”
Diagnostic claims often fail because they recite a biological relationship without adding significant innovation. Courts have rejected methods that simply tell a practitioner to observe something already occurring in the body, such as a biomarker level that correlates with a condition.
Examples of what may be considered a natural law:
- A gene variant linked to a specific disease
- A protein level associated with treatment response
- A metabolic change that predicts a disorder
These correlations alone are not patentable. What matters is how you use the information.
Strategies to Make Diagnostic Claims More Defensible
Biotech developers can improve patent eligibility by ensuring the method includes concrete, technical, non-routine steps. When drafting or refining claims, we encourage you to focus on the method’s real-world function.
Stronger diagnostic method claims often include:
- A defined laboratory technique or molecular process
- A multi-step protocol that would not be performed mentally
- A specific detection platform or measurement technique
- A transformation of the sample or analyte
- An algorithmic or computational feature applied in a structured way
Adding more steps does not automatically make a diagnostic method patentable. Examiners look for steps that contribute meaningfully to the innovation rather than actions that feel standard or conventional in the field.
How the USPTO Currently Treats Diagnostic Method Filings
The USPTO regularly updates guidance on patent subject matter eligibility, and diagnostic claims remain one of the most scrutinized categories. Examiners tend to:
- Cite prior case law quickly when natural correlations appear
- Ask for clarification on what makes the method non-routine
- Require evidence that each claimed step adds practical value
Filing with a well-developed description and claim set helps minimize rejections. Early coordination between research teams and patent counsel also reduces the risk of narrowing claims too much during prosecution.
When Diagnostic Methods Are More Likely to Be Approved
Patent protection becomes more achievable when the innovation:
- Uses a new reagent, probe, or detection tool
- Requires a series of specific, technical steps
- Relies on a novel machine or transformative action
- Produces a result that cannot be obtained through simple observation
In other words, when the method applies biological insight in a structured, technical way, examiners have clearer grounds to find eligibility.
Common Mistakes Inventors Make With Diagnostic Patents
We often see biotech teams run into trouble because of a few predictable issues. Before filing, you can avoid setbacks by watching for:
- Insufficient technical detail. A vague method rarely satisfies eligibility or novelty requirements.
- Overreliance on the biological correlation. The correlation supports the invention, but it cannot be the invention by itself.
- Submitting too early. If research protocols are still changing, the claims may not reflect the eventual method.
- Not documenting non-routine steps. Examiners need clear, written evidence that the method adds something more.
Why This Matters for Biotech Companies
Uncertain patentability can delay investment, slow regulatory planning, or limit competitive advantage. Diagnostics are often paired with therapeutic development or platform-based R&D, so protecting the method can open the door to wider patent strategies.
Strong diagnostic patents can:
- Support valuation during fundraising
- Strengthen licensing opportunities
- Provide leverage against competitors using similar technology
- Protect long-term R&D pipelines
Protecting Your Diagnostic Method With Skilled Patent Counsel
Securing a patent for a diagnostic method requires careful claim drafting, strategic planning, and a deep understanding of current eligibility rules. At Gearhart Law, we help innovators build strong, defensible protection for diagnostic tools, biotech processes, and life-science breakthroughs.
If you are preparing to patent a diagnostic method or want guidance on strengthening your application, contact us to discuss your strategy.