When analytical labs are trying to decide which Good Practices they should adopt, there is bound to be confusion. Fortunately, the FDA in coordination with the International Conference on Harmonization (ICH), issued guidance documents on each of the GxPs including Good Clinical Practices (GCP), Good Laboratory Practices (GLP and current Good Manufacturing Practices (cGMP). The cGMP has the most valuable guidance for analytical labs.
GCP
GCP, described in ICH E6 Good Clinical Practice: Consolidated Guidance, is the quality standard for designing, conducting, recording, and reporting human clinical trials. There is little guidance for analytical labs. It only states that the sponsor is responsible for implementing and maintaining quality assurance and quality control systems with written SOPs and ensuring that data are in compliance with the protocol.
GLP
GLP requirements are in the Federal Register (CFR 21 Part 58) under the title “GOOD LABORATORY PRACTICE FOR NONCLINICAL LABORATORY STUDIES”. It primarily applies to animal studies that are done to evaluate toxicity, safety pharmacology and other attributes of a chemical entity. It is mostly concerned about the animal facilities and the care of the animals. There are analytical practices in the guidance, but these mostly deal with the handling of the test article. While many analytical chemists hope to find good ways to run their laboratories in the GLPs, they are usually disappointed once they get in the details of this guidance.
GMP
There are GMPs for finished pharmaceuticals, foods and medical devices. The GMPs for pharmaceuticals (21 CFR Part 211 CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS) actually have the best information for organizing and administering analytical labs. The section on Laboratory Controls contains the most detailed requirements on documentation, instrument calibration and method validation.
If a lab is looking for best practices for analytical work that is in compliance with GxPs, their best bet is to follow the laboratory controls in the current Good Manufacturing Practices for finished pharmaceutical products.