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GLP vs. Non-GLP Assays: When Each Is Appropriate & How to Validate Them

Why the Distinction Matters

In drug development, bioanalytical assays generate the data that drives critical decisions, whether a molecule advances, pivots, or stops. But not all assays need to be conducted under the same regulatory rigor. Understanding the difference between Good Laboratory Practice (GLP) assays and non-GLP assays is essential for sponsors who want to balance speed, cost, and regulatory readiness.

At InfinixBio, we can guide sponsors through when GLP is required, when non-GLP is appropriate, and how to validate assays to satisfy regulatory expectations without over-investing too early.

What Are GLP Assays?

GLP assays are conducted under formal Good Laboratory Practice regulations (FDA, 21 CFR Part 58) that ensure:

• Data integrity and reproducibility
• Standardized procedures and documentation
• Quality assurance oversight
• Traceability for regulatory submissions

They are typically required for toxicology studies, bioanalytical method validation, and IND-enabling programs, where data will be submitted to regulatory authorities.

When GLP assays are appropriate:

• IND or CTA submissions
• Safety pharmacology or toxicokinetic studies
• Pivotal preclinical data packages that regulators will review
• Confirmatory bioanalysis supporting Phase I trials

What Are Non-GLP Assays?

Non-GLP assays follow scientific best practices but are not conducted under formal GLP compliance systems. They are faster, more flexible, and often less costly, making them ideal for early discovery and exploratory programs.

When non-GLP assays are appropriate:

• Lead optimization and candidate selection
• Early pharmacokinetic (PK) screening
• Exploratory biomarker studies
• Feasibility testing of new assay formats
• Pilot studies to de-risk larger GLP programs

How to Decide Between GLP and Non-GLP

Choosing the right path depends on the objective of the study and regulatory intent:

• If data will go into a regulatory submission → GLP is required.
• If data is internal or exploratory → non-GLP may be sufficient.

Sponsors often start with non-GLP to explore feasibility, then transition to GLP once a molecule is ready for IND-enabling studies.

Assay Validation Best Practices

Regardless of GLP status, assays should be scientifically rigorous. Validation ensures the assay performs consistently and produces reliable results.

Key validation parameters include:

• Accuracy & precision – Does the assay measure the analyte correctly and reproducibly?
• Selectivity & specificity – Can the assay distinguish the analyte from other components?
• Sensitivity (LLOQ/ULOQ) – Are the Lower and Upper detection limits appropriate for the study?
• Stability – Does the analyte remain stable in matrix and under study conditions?
• Reproducibility – Can results be replicated across analysts, runs, and instruments?

For GLP validation, additional requirements include documentation, independent QA audits, and adherence to regulatory guidelines (FDA, EMA, ICH M10).

How InfinixBio Supports Sponsors

At InfinixBio, we provide end-to-end bioanalytical support that spans both GLP and non-GLP needs:

• Non-GLP feasibility and method development for early-stage decision-making
• GLP-compliant method validation to support IND and Phase I submissions
• Flexible, fit-for-purpose study design aligned with your program’s stage and risk profile
• Regulatory expertise to ensure data packages meet FDA and EMA expectations

Our scientifically rigorous and operationally agile approach ensures you get the right level of compliance at the right stage—avoiding wasted resources while building a solid foundation for regulatory success.

Ready to design the right assay strategy for your program?

Connect with InfinixBio today to learn how our experts can support both GLP and non-GLP assay development and validation, helping you move forward with confidence.