LDT Education
Laboratory-developed tests (LDTs) offer tailored clinical diagnostic solutions that allow greater flexibility and innovation compared to in vitro diagnostic (IVD) tests. Both LDTs and IVDs are valuable diagnostic tools, and each have advantages and limitations.
LDT vs IVD
Laboratory-developed tests (LDTs) and in vitro diagnostic tests (IVDs) both play crucial roles in clinical diagnostics, but they differ significantly in their development, regulation and use. Each test type has unique strengths, making them suited for different diagnostic contexts. IVDs are ideal for widespread, standardized testing, while LDTs offer more flexibility and customization, particularly in emerging or niche areas of medicine.
| LDT | IVD | |
|---|---|---|
| Development & Design | Tests developed and used within a single laboratory, usually for specialized diagnostic purposes. LDTs are typically tailored to the needs of the lab's patient population and are only available within one lab. | Commercial tests developed by medical device manufacturers for widespread use in multiple clinical labs. IVDs are typically standardized, mass-produced and sold as kits or instruments. |
| Regulation | Regulatory oversight of LDTs varies by country. | IVDs are regulated by regulatory bodies around the globe (e.g., the U.S. Food and Drug Administration [ FDA] and the European Medicines Agency [EMA]). IVDs must undergo rigorous premarket review processes to demonstrate their safety, efficacy and performance before they are allowed to be marketed. |
| Validation & Approval | Globally, LDTs do not typically undergo the same level of external review and approval as IVDs, and the developing lab is responsible for internal validation of the test’s performance. LDTs in the U.S. must meet the Clinical Laboratory Improvement Amendments (CLIA) standards for accuracy, reliability, and performance. In other regions, LDTs are regulated by local or regional standards, which may vary in terms of oversight and requirements. | IVDs undergo a formal validation processes with extensive clinical trials and data submission to regulatory bodies for approval or clearance (e.g., FDA 510(k) clearance or CE marking). |
| Use & Availability | Only available within the laboratory that developed the test. These tests are often customized to address specific diagnostic needs that may not be met by commercial IVDs. | Widely available and used across multiple labs and healthcare settings. IVDs are designed to be standardized and used by a broad range of labs. |
| Innovation & Flexibility | LDTs can be more flexible and innovative. They are often developed to quickly address emerging medical needs, especially in academic or research institutions. They are commonly used for specialized tests, such as those in oncology or genetics. | Due to strict regulatory processes, IVDs tend to be more standardized but may lag in incorporating the latest scientific advances or addressing niche diagnostic needs. |
| Cost | The cost of LDTs can vary greatly, as they are typically developed and validated within the lab and may not require investment in specific, proprietary instruments like IVDs. | IVD tests can be more cost-effective on a large scale because they are mass-produced and sold commercially. However, they may require significant upfront investment in instruments or systems. |
| Examples | Genetic sequencing for rare diseases, specific cancer biomarker panels or highly specialized pathology tests. | Blood glucose meters, COVID-19 rapid tests, HIV testing kits and pregnancy tests. |
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| Limitations |
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In summary:
| LDT | IVD | |
|---|---|---|
| Regulation | Less stringent and varies by country | Strict (FDA, EMA, etc.) |
| Flexibility | High (quickly adaptable) | Limited (due to regulatory processes) |
| Innovation Speed | Faster (rapidly developed for specific needs) | Slower (due to approval timelines) |
| Availability | Limited to the lab that develops it | Widespread and commercial |
| Cost | Lower upfront, but variable ongoing costs | High upfront costs (instruments, kits) |
| Standardization | Variable (test quality depends on the lab) | High (consistent performance across labs) |
| Reimbursement | Often harder to get insurance coverage | More likely to be reimbursed by insurers |
| Customization | High (custom-tailored to specific needs) | Low (standardized for mass use) |
LDT Regulations
The regulatory oversight of LDTs varies significantly by country, reflecting differences in health policies, regulatory frameworks and the role of clinical laboratories. Although LDT oversight is generally less stringent than for IVDs, the level of regulation is gradually increasing in many regions, particularly as tests become more complex and widely used.
Promega is committed to supporting your clinical lab as you navigate the regulations in your region. We share a collective goal with you of supporting and advancing patient care.
Quality Management Systems
Implementing a mature quality management system (QMS) can be challenging. If you need to implement a QMS in your lab to meet regulatory requirements, choosing a partner with a well-implemented QMS can save you time and money and eliminate the need to build all the controls yourself.
One of the largest benefits of partnering with a manufacturer who regularly operates under a QMS is the improved consistency in the final product. Manufacturing products using documented processes and procedures performed by qualified and trained personnel will result in the supply of a consistently performing product on time, every time. Additionally, in the unlikely occurrence of a non-conforming product, a partner with a QMS in place will have the systems and expertise to facilitate any necessary product investigations.
Finding the right manufacturing partner can be challenging. Evaluating a potential partner’s manufacturing capabilities requires an understanding of how they manage and control their manufacturing operations to ensure your product is delivered on time—and to your specifications—every time.
Learn more about what a QMS is and the considerations for building an effective QMS in this webinar.
FDA QSIT Guide. The illustration shows seven subsystems along with related satellite programs.