Central vs. Local Labs: Advantages, Problems, and the Challenges of Unit Standardization in Clinical Trials
Introduction:
Clinical laboratory data plays a crucial role in determining the safety and efficacy of new pharmaceutical agents during clinical trials. This data is typically handled by two types of labs: central labs and local labs. In this article, we will discuss the advantages and problems associated with each type of lab and explore the challenges surrounding unit standardization.
Central Labs:
Central labs, such as Covance, CCLS, and Quintiles, are specialized laboratories that are responsible for handling laboratory data from multiple clinical trial sites. The main advantage of central labs is that they use standardized procedures for conducting tests, which ensures consistency and facilitates direct comparison among patients. Data from central labs is usually provided electronically, which saves time and effort. Moreover, the central lab applies normal ranges to each patient and lab test, and provides the results in the units specified by the sponsor or in a common unit based on their own defaults.
However, the main drawback of central labs is that there is a delay in obtaining results, as the samples need to be sent to the central lab for analysis. This delay can be problematic in some cases where an immediate result is needed to allow dosing or entry into the trial.
Local Labs:
Local labs are general on-site labs located within the hospital or medical unit where the patient visit is taking place. These labs are most often used when an immediate result is needed to allow dosing or entry into the trial. The data from local labs is usually captured directly on the case report form.
One advantage of local labs is that they provide immediate results, which can be crucial in some situations. However, local labs are complicated by the fact that normal ranges may not be readily available, and the unit of collection may vary from lab to lab. Standardization of results to a single unit is often required, which can be challenging.
Unit Standardization:
Unit standardization is the process of converting laboratory test results from one unit to another. This is necessary when laboratory tests are conducted in different units, making direct comparison difficult. Standardization is typically required when combining data from central and local labs, or when comparing data from different studies or countries.
The SAS® software provides several methods for unit conversion, including the FORMAT and LABEL statements, the INPUT and PUT functions, and the use of informats and formats. These methods are essential for ensuring that laboratory data is consistent and can be accurately compared.
Conclusion:
In summary, laboratory data is a critical component of clinical trials, and the handling and analysis of this data can vary depending on whether it is handled by a central or local lab. Each type of lab has advantages and drawbacks, and careful consideration should be given to the selection of the appropriate lab for each study. Unit standardization is also essential for ensuring that laboratory data can be accurately compared, and SAS® provides several methods for achieving this standardization.
