This article is the second in a series of three by Senior Scientist James Markwiese, PhD, discussing the quality control and quality assurance measures for state-of-the-practice toxicity testing. The series focuses on mechanisms to facilitate the establishment and documentation of quality procedures for toxicity testing laboratories. The first article in this series is available here. The third article in this series is available here.
A laboratory must actively ensure that its quality system is being properly implemented and that it is achieving the required standard of quality. Quality control measures, such as a method-specific demonstration of bioassay capability, can provide feedback on the quality system but are not enough to ensure quality results. Audits are designed to provide an objective and thorough evaluation of quality issues affecting a laboratory and cover the entirety of the quality system. Routine audits of toxicity testing laboratories can detect actual or potential non-conformances before they impact data quality and can even identify possible future problems. Where there are no problems, the audit provides a record that the quality assurance system has been thoroughly evaluated and found to be acceptable.
The quality assurance elements reviewed in a toxicity testing audit include:
- quality documents such as quality management plans, study plans including quality assurance sections and standard operating procedures;
- records including technician training, Chain-of-Custody, equipment calibration such as dosimetry, pH, salinity and light meters, test conditions, toxicity test data and reports and corrective actions;
- and methodology including test implementation and performance.
These topics can be covered in any order, but typically begin with an evaluation of documentation and records and end with method/ test performance review.
The most important, and perhaps most difficult to gauge, aspect of the latter involves evaluating competence of laboratory personnel for routine maintenance, such as culture of test organisms. For confidence in bioassay results, it is imperative to demonstrate that the organism is responding to the test substance and/or conditions and not some confounding factor (lack of acclimation to test conditions, disease, etc.). Validity of results can be evaluated on a test-specific basis and efforts are underway to gauge long-term performance of testing laboratories. Although audits typically only last from one to several days, and therefore represent a narrow window for gauging year-round laboratory operations, they offer an unparalleled means for evaluating a laboratory’s implementation of its quality assurance system.
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