1. General Considerations
The growing emphasis on microorganisms in water quality standards and enforcement activities and their continuing role in research, process control, and compliance monitoring require the establishment and effective operation of a quality assurance (QA) program to substantiate the validity of analytical data.
A laboratory quality assurance program is the integration of intralaboratory and interlabortory quality control (QC), standard-ization, and management practices into a formal, documented pro-gram with clearly defined responsibilities and duties to ensure that the data are of the type, quatity, and quantity required.
The program must be practical and required only a reasonable amount of time or it will be bypassed . Generally, about 15% of overall laboratory time should be spent on different aspects of a quality assurance program. However, more time may be needed for more important analytical data, e.g., data for enforcement actions. When properly administered, a balanced, conscientiously applied QA program will optimize data quality without adversely affecting laboratory productivity.
Because microbiological analyses measure constantly changing living organisms, they are inherently variable. Some quality control tools used by chemists, such as reference standards, instrument calibration, and quality control charts, may not be available to the microbiologist.
Because QA program vary among laboratories as a result of differences in organizational mission, responsibilities, and objectives; laboratory size, capabilities, and staff skills and training, this provides only general guidance. Each laboratory should determine the appropriate QA level for its purpose.