Quality assurance programs

The "feedback loop in the analytical approach is maintained by a quality assurance program (Figure 15.1), whose objective is to control systematic and random sources of error.The underlying assumption of a quality assurance program is that results obtained when an analytical system is in statistical control are free of bias and are characterized by well-defined confidence intervals. When used properly, a quality assurance program identifies the practices necessary to bring a system into statistical control, allows us to determine if the system remains in statistical control, and suggests a course of corrective action when the system has fallen out of statistical control. 

The focus of this chapter is on the two principal components of a quality assurance program quality control and quality assessment. In addition, considerable attention is given to the use of control charts for routinely monitoring the quality of analytical data. 

The written directives of a quality control program are a necessary, but not a sufficient, condition for obtaining and maintaining an analysis in a state of statistical control. Although quality control directives explain how an analysis should be properly conducted, they do not indicate whether the system is under statistical control. This is the role of quality assessment, which is the second component of a quality assurance program. 

Internal methods of quality assessment should always be viewed with some level of skepticism because of the potential for bias in their execution and interpretation. For this reason, external methods of quality assessment also play an important role in quality assurance programs. One external method of quality assessment is the certification of a laboratory by a sponsoring agency. Certification is based on the successful analysis of a set of proficiency standards prepared by the sponsoring agency. For example, laboratories involved in environmental analyses may be required to analyze standard samples prepared by the Environmental Protection... 

In the previous section we described several internal methods of quality assessment that provide quantitative estimates of the systematic and random errors present in an analytical system. Now we turn our attention to how this numerical information is incorporated into the written directives of a complete quality assurance program. Two approaches to developing quality assurance programs have been described a prescriptive approach, in which an exact method of quality assessment is prescribed and a performance-based approach, in which any form of quality assessment is acceptable, provided that an acceptable level of statistical control can be demonstrated. 

Quality assurance programs are designed to serve two functions (1) assessment of collected air quality data and (2) improvement of the data collection process. These two functions form a loop as air quality data are collected, procedures are implemented to determine whether the data are of acceptable precision and accuracy. If they are not, increased quality control procedures are implemented to improve the data collection process. 

The components of a quality assurance program are designed to serve the two functions just mentioned—control and assessment. Quality control operations are defined by operational procedures, specifications, calibration procedures, and standards and contain the following components ... 

List the two major functions of a quality assurance program and describe how they are interrelated. 

Data from monitoring programs cannot be evaluated with confidence unless adequate quality assurance has been Incorporated Into the program designs. A good quality assurance program enables sources of error associated with each step of the monitoring efforts to be Identified and quantified. 

The individual scientist is the key to the production of quality data and must have technical competence and a dedication to quality work. Passive following of good laboratory practices and good measurement practices is not enough. Involvement in their development is required if the quality assurance program is to be credible. Standard operations procedures (SOPs) do not minimize the need for technical competence. Analysts exhibit varying degrees of proficiency when... 

Monitoring programs must have their own quality assurance programs. These may be called project quality assurance plans or protocols for specific purposes O). If reliable vendors of services are used, the bulk of the quality assurance effort can be placed on those activities unique to the program. Without reliable vendors, QA efforts will be ineffective since it is not cost effective to police quality assurance practices at all lower levels nor to screen all data for its validity. 

Support for sites is multi-tiered and includes participation by numerous federal, state, private, academic, and tribal organizations. Network operation includes rigorous field and laboratory quality assurance/quality control (QA/QC), including an external quality assurance program and periodic external on-site audits. 

Abreu SH (1996) The nature of quality assurance in nuclear medicine and the American College of Nuclear Physicians quality assurance programs. Eur Nuclear Med 23(i) 99-io3. 

Parr RM, Fajgelj A, Dekner R, Vera Ruiz H, Carvalho FP, and Povinec PP (1998) IAEA analytical quality assurance programs to meet the present and future needs of developing countries. Fresenius J Anal Chem 360 287-290. 

A quality assurance program statement listing the types of inspections made and their dates, including the phases inspected, and the dates when any inspection results were reported to management, to the Study Director, and to any Principal Investigators, if applicable. This statement would also serve to confirm that the final report reflects the raw data. 

Each contract laboratory used in the QPMBS and the organization that coordinated the field phase already had in place a well-defined GLP-compliant quality assurance program. In addition to these existing quality assurance programs, an independent QA specialist was engaged to ensure compliance of all the aspects of the smdy with GLP requirements. 

These efficiencies assume proper, leak-free installation. Filters are often improperly installed and sometimes missing. Reliance on filtration requires a quality-assurance program to ensure that filters are in place and functioning. 

Yen-Lieberman, B et al. (1996). Evaluation of a quality assurance program for quantitation of human immunodeficiency virus type I RNA in plasma by the AIDS Clinical Trials Group Virology Laboratories. J. Clin. Microbiol. 34,2695-2701. 

The management system for process definition documentation should ensure that the contents of the process documentation package are accurate and complete. A suitable review and quality assurance program should be implemented for the process documentation. This may involve a hierarchical review process, and/or using external experts in a review capacity. 

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