Starting a lab job and hearing “we work under GLP” can feel daunting. Good laboratory practice is a quality system for safety studies: plan it, document it, and make every result traceable.
This guide sits within our wider lab skills series for people building a biotech career.
| Item | Key fact |
|---|---|
| Main US rule | 21 CFR Part 58 |
| OECD Principles of GLP | Revised in 1997 |
| International data-sharing idea | “Tested once, accepted for assessment everywhere” |
| Person responsible for a study | One study director |
| Quality oversight | A quality assurance unit separate from the study director |
Figures come from the eCFR text of 21 CFR Part 58 and the OECD GLP questions and answers. Rules can change, so check the sources before you rely on them.
What good laboratory practice actually is
GLP is not a technique like pipetting. It is a set of management and documentation rules that decide how a study is organised, recorded and reported.
The aim is trust. Regulators making decisions about the safety of chemicals and products want confidence that the data behind those decisions is valid and of high quality, and GLP is how that confidence is built.
It is easy to confuse GLP with other “G” systems. GLP covers nonclinical safety studies, while manufacturing falls under the rules described in our gmp basics guide.
Which studies fall under GLP?
In the US, the FDA regulation defines a nonclinical laboratory study as “in vivo or in vitro experiments in which test articles are studied prospectively in test systems under laboratory conditions to determine their safety.”
The OECD Principles take a similar view. They concern non-clinical testing of a chemical or chemical product, examined under laboratory conditions or in the environment, including work conducted in greenhouses and in the field.
In practice, this means GLP shows up in areas such as:
- Toxicology studies that support a regulatory submission.
- Safety testing of chemicals and chemical products.
- Some non-clinical safety testing of other regulated products, depending on the jurisdiction.
Early exploratory research usually does not need GLP. If you are optimising an assay or growing cells for discovery work, your lab may follow looser internal rules, though skills such as those in cell culture techniques still carry over.
The two main frameworks: FDA and OECD
Two documents come up most often. The first is the US rule, 21 CFR Part 58, which covers nonclinical studies supporting applications for research or marketing permits.
The second is the OECD Principles, which were revised in 1997 and are used across many countries. Both describe similar building blocks, so skills learned under one transfer well to the other.
The OECD system matters because of mutual acceptance of data. Under mutual acceptance of data, adherent countries accept qualifying data generated according to OECD Test Guidelines and GLP Principles in other adherent countries for assessment without requiring duplicate testing.
The FDA also has leverage. Under its rule, the agency will not consider a study in support of an application if the testing facility refuses to permit inspection.
Core building blocks of a GLP study
Although wording differs between frameworks, a GLP lab shows the same features. The list below is based on the FDA regulation.
- Defined roles. A study director is the individual responsible for the overall conduct of the study.
- Independent quality assurance. The quality assurance unit is designated by facility management and is separate from the study director.
- Written procedures. Standard operating procedures (SOPs) set out routine methods, and equipment procedures cover inspection, cleaning, maintenance, testing and calibration.
- A protocol. Each study follows an approved plan.
- Raw data and records. Original observations are kept so the study can be reconstructed.
- Archives. Space is provided with access limited to authorised personnel for raw data and specimens from completed studies.
Raw data, deviations and what quality assurance checks
The FDA defines raw data as laboratory worksheets, records, memoranda, notes, or exact copies of them that result from original observations and are necessary for reconstructing and evaluating the study report. That can include printouts, magnetic media and recorded data from automated instruments.
When something goes off plan, you do not quietly fix it. All deviations from SOPs have to be authorised by the study director and documented in the raw data.
The quality assurance unit acts as a check. Among its duties, it maintains a master schedule of all studies and reviews the final report to make sure the results accurately reflect the raw data.
The unit also determines that no deviations from approved protocols or SOPs were made without proper authorisation and documentation.
Habits that help you in a GLP lab
If you are new, the cultural side matters as much as the regulations. These habits are common sense rather than legal text, but they match what the rules reward.
- Record data at the time you observe it, clearly and legibly.
- Follow the current SOP, and ask before you improvise.
- Tell the study director about any deviation straight away.
- Keep equipment records and reagent labels complete.
- Treat the audit trail as part of the experiment, not paperwork afterwards.
Employers value these habits because a result that cannot be traced is hard to defend, however good the science.
How GLP fits into a biotech career
Many entry-level roles in toxicology, analytical chemistry, bioanalysis and quality assurance sit inside GLP facilities. Knowing the vocabulary before your first interview shows employers that you understand why documentation matters.
You can build useful habits long before you join such a lab. Keep a clear notebook during coursework, write down deviations honestly, and learn to read an SOP closely enough to follow it step by step.
Roles in a GLP setting tend to split along the lines the regulation sets out:
- Study staff carry out the work and record raw data as they go.
- The study director owns the scientific conduct and the final report.
- Quality assurance staff audit the study independently of the people running it.
- Facility management designates the quality assurance unit and provides the facilities and resources.
If you enjoy detail, process and clear writing, quality assurance can be a rewarding path. If you prefer bench science, you will still be judged on how well your records stand up when someone else reads them.
Common misunderstandings about GLP
A frequent myth is that GLP guarantees the science is correct. It does not. GLP is about data integrity and traceability, so a reviewer can see what was done, by whom and with what materials, and then judge the results.
Another myth is that GLP only matters at the end of a study. In reality, the planning stage matters most, because the protocol, the SOPs and the equipment checks all need to be in place before the first measurement is taken.
A third is that paperwork is a burden separate from the real work. Under GLP, the record is part of the result: if a result cannot be reconstructed from the raw data, regulators have little reason to rely on it.
Finally, remember that GLP rules vary by country and by product type. The OECD system helps by letting data be shared among adherent countries, but you should always read the framework your own facility works under.
Frequently asked questions
Is GLP the same as GMP?
Show answer
No. GLP governs how nonclinical safety studies are planned, run and reported, while GMP concerns manufacturing quality.
Does all lab research have to follow GLP?
Show answer
No. The FDA regulation applies to nonclinical studies that support or are intended to support applications for research or marketing permits. Basic discovery work usually sits outside it.
What does “mutual acceptance of data” mean?
Show answer
Data generated under the OECD Test Guidelines and Principles of GLP in one adherent country is accepted for assessment in others, so the study does not have to be repeated.
Who is responsible for a GLP study?
Show answer
The study director has overall responsibility. Quality assurance is handled by a separate unit.
