Several other organizations issue recommendations, such as the National Conference of Standards Laboratories (NCSL) International, which issued Recommended Practice 6 (RP-6) to help biomedical and pharmaceutical laboratories establish effective calibration control systems. In many ways, RP-6 is a complement to GAMP. Written from a metrology and equipment management perspective, RP-6 emphasizes the nuts and bolts, such as calibration and measurement traceability, calibration history records and good labeling practices. The recommendations in RP-6 help laboratories move towards establishing calibration programs that are in compliance with 21 CFR 211.

The Association of Analytical Communities (AOAC), whose vision is "worldwide confidence in analytical results," is another agency that directs quality assurance initiatives. The organization's standard, entitled "Accreditation Criteria for Laboratories Performing Microbiological and Chemical Analyses in Foods, Feeds, and Pharmaceutical Testing," includes the full text of ISO 17025, with additional appended information to benefit the target laboratories.

Appendix A establishes a minimum calibration frequency of every three months for "volumetric delivery devices" (including mechanical action pipettes and mechanical burettes) and notes that "all data acquired on instruments that fail a parameter are suspect between the failing assessment date and the last successful calibration or verification date."

The American Society for Testing and Materials (ASTM International), develops market-relevant standards on a global scale. ASTM International standard E1154 states that liquid-delivery device calibration should be performed every three months with 10 data points, while a "quick check" verification should be performed every month with four data points. This standard is not required practice in the pharmaceutical industry, but it does provide a point of reference for laboratories evaluating internal programs. It is one of the few standards that make specific recommendations for both frequency and number of data points in pipette calibration.

INTERNATIONAL GUIDELINES

Because of the globalization of the pharmaceutical industry, international organizations are emerging to provide border-spanning guidance to the vast number of companies operating in multiple countries. For example, the International Organization for Standardization (ISO) emerged as a key global guiding body for a range of industries, particularly laboratories. A nongovernmental organization, this network identifies and adopts relevant standards that can improve practices and ensure quality in products and services. These standards are highly useful for international companies to coordinate laboratory operations and maintain consistent quality programs worldwide.

ISO 17025 presents general requirements for the competence of testing and calibration laboratories, and includes both quality system and technical requirements. This standard does not address the specifics of liquid handling, but does state that all equipment that can contribute significant uncertainty must be calibrated using traceable means and with a stated uncertainty. For nearly all analytical methods, liquid handling undoubtedly falls into this equipment category. Also in ISO 17025 is the recommendation that standard calibration and check methods be used as they are more easily validated and less expensively defended in audits. A growing list of FDA laboratories are ISO 17025 accredited, including district and regional laboratories in Arkansas, California, Colorado, Pennsylvania, and Washington, providing evidence of FDA's support of this standard.

To provide further guidance to laboratories, ISO Technical Committee 48 released a seven-part series, ISO 8655, defining accepted liquid delivery performance and calibration practices. Parts one through five define and specify minimum performance requirements for accuracy and precision in liquid handling.

The next two sections of ISO 8655 provide guidance regarding accepted methods for verifying performance of liquid delivery devices. Part 6, released in 2002, discusses gravimetric calibration, which verifies liquid volumes by measuring weight on a balance.