Traceability ensuring

Establishing the traceability of the measurement is one of the most important requirements in ISO/IEC 17025. Measurement traceability ensures that the measurements in different laboratories are comparable in space and time all over the world. Calibration and the use of certified reference material (see chapters 9, 10 and 14) is the central tool in establishing trace-ability. Therefore a laboratory must have programmes and procedures for both. 

The general purpose of an audit may be to determine if the toller has management systems and documented procedures in place to ensure process safety, environmental responsibility, product quality and traceability of materials. The need to audit could be to evaluate compliance with regulations or accordance with client requirements related to specific performance elements. A subjective rating system for ranking management systems audit results is often used. An example of one that might be appropriate is shown below ... 

In the upper diagram each supplier individually interprets the customer s requirements and either imposes additional requirements or neglects to pass on requirements. The net result at the end of the chain is that the external customer (the one who buys from the organization) does not get satisfaction from the transaction. In the lower diagram, each supplier refers back to the external customer s requirements to calibrate the internal customer s demands. This ensures that the net result matches exactly what the customer ordered. In reality, such calibration should not be necessary if the internal customers demonstrate traceability to external customer requirements. This can be achieved through process reviews performed in each process before instructions are transmitted to subsequent processes. 

Do ensure signatures are legible and traceable to those with the necessary authority. 

Ensure that all documents not traceable to the published policies and procedures are removed or identified as uncontrolled. 

How do you ensure traceability of product to original material identification, quality status, and the unit responsible for both its supply and verification ... 

The standard also requires that the instructions be derived from appropriate sources, such as the quality plan, the control plan, and the product realization process, which means that all instructions should be traceable to one or more of these documents. They should form a set, so that there are no instructions used outside those that have been approved by the planning team. This is to ensure that no unauthorized practices are employed. Another important aspect to consider is the use of informal practices - practices known only to the particular operator. Process capability should be based on formal routines, otherwise repeatability cannot be assured when operators change. 

Although the work of ATCC and others has done much to ensure the reproducibility and even demonstrate some traceability of microbiological reference materials the development of microbiological Certified Reference Materials (CRMs), certified for number of viable life forms is seen as important for control analyses of water and food. Somewhat of a holy grail the development of such CRMs has long been hampered by the unstable concentration and insufficient homogeneity of viable organisms in the materials. 

A second reason for using reference materials in clinical chemistry is to ensure values obtained are traceable to those in a recognized, authoritative reference material (Johnson et al. 1996). As a result, the assignment of values of secondary and tertiary reference materials, calibrants, controls, and proficiency samples shordd be performed as precisely as possible (Johnson et al. 1996). Surprisingly there is still debate on this topic, and on the need for clinical chemistry to incorporate the principals of analytical quality assurance (Dybkaer et al. 1999). 

More attention should be devoted to the quantitative determination of analytes in real-life samples. The accuracy of the determinations and the traceability of the overall analytical process are insufficiently ensured [120,121], As no primary methods are available for the purpose, this necessarily implies the use of certified reference materials. 

It is important that a measurement made in one laboratory by a particular analyst can be repeated by other analysts in the same laboratory or in another laboratory, even where the other laboratory may be in a different country. We aim to ensure that measurements made in different laboratories are comparable. We are all confident that if we measure the length of a piece of wire, mass of a chemical or the time in any laboratory, we will get, very nearly, the same answer, no matter where we are. The reason for this is that there are international standards of length, mass and time. In order to obtain comparable results, the measuring devices need to be calibrated. For instance, balances are calibrated by using a standard mass, which can be traced to the primary mass standard (see also Chapter 5). The primary standard in chemistry is the amount of substance, i.e. the mole. It is not usually possible to trace all of our measurements back to the mole. We generally trace measurements to other SI units, e.g. mass as in 40 mg kg-1 or trace back to reference materials which are themselves traceable to SI units. 

In addition, a system for making sure staff are appropriately qualified and trained for the work that they are doing must be in place. This will enable an auditor to see clearly the demonstrated competence of the staff and how this has been checked. The requirements for all major items of equipment must be listed, to ensure that the equipment in use is suitable for the task, is in working condition and, where necessary, is calibrated. For all of the instrumentation there needs to be a documented schedule for maintenance. Measurements must be traceable, that is, the laboratory must be able to show how the calibration of measurement instruments is traceable to National or International Standards. Where this presents practical problems, as in some chemical measurements for example, interlaboratory comparison and the use of reference materials (and preferably Certified Reference Materials) will be required. 

These aims reach much further than the UK as evidenced by other international organizations which have developed, partly as a result of the work in VAM. They include Eurachem (a network of organizations in Europe having the objective of establishing a system for the international traceability of chemical measurements and the promotion of good quality practices) and CITAC (Co-operation on International Traceability in Analytical Chemistry). A wide variety of issues have been identified, all of which need to be addressed to ensure that analytical measurements made in different countries or at different times are comparable. 

In conclusion, one must insist on the importance of the main metrological characteristic, the traceabilility (generally of a result), ensuring a clear (unbroken) relationship between the final result and the complete measurement scheme by using appropriate procedures, standards and calibrated equipment. However, for chemical metrology and particularly for on-site measurement, some adaptations are needed for a wider meaning of traceability [66]. 

The highest quality reference materials are certified for the concentration values of the constituent(s) of interest, reflecting high confidence in the value s accuracy and the thorough investigation of all known or suspected sources of bias. Used appropriately (e.g., Roper et al., 2001 Zschunke, 2000), these certified values provide an effective means to ensure comparability (both among laboratories and over time). It is not always practical, however, to undertake the work required to produce a certified value in many such cases, a value can be carefully determined, but insufficient information exists to assess the associated uncertainty. This information value is nevertheless of substantial interest to other users of the reference material. It can, for example, allow laboratories to compare results even though full traceability is impractical. 

The programmes for calibration of equipment shall be designed and operated in a way to ensure that calibrations and measurements made by the calibration laboratory are traceable to the International System of Units (SI) (Systeme international d unites). 

To ensure the trackability (traceability to the raw data) of analytical results, the laboratory shall have a system to identify test and/or calibration items uniquely. The identification shall be retained throughout the life of the item in the laboratory. 

If we use a standard solution traceable to a stated reference, we ensure the traceability of our measurement by extending the traceability chain (for more details on traceability see chapter 10). 

Starting with the calibration, the certified reference material can be used as a calibrant (directly or via working standards prepared using them) and in this way traceability of the results to the property values of the certified reference material is ensured. Thus this is a very valid way for certified reference materials to improve the measurements in a laboratory. 

The IQ protocol should ensure that instmmentation has been calibrated according to approved procedures and that the measurements are traceable to defined national or international standards. All such calibrations and detailed control parameters must be recorded and records securely kept. 

Quevauviller, Ph., and Donard, O. F. X. (2001), Stated references for ensuring traceability of chemical measurements for long-term environmental monitoring, Trends Anal. Chem., 20, 600-613. 

If the analyst in a field laboratory can identify a CRM for calibration of working calibration solutions, and its certificate gives sufficient evidence that the CRM embodies a metrologically traceable quantity value, then his or her work is just about done (figure 7.10). The intricacies of what national measurement institutes and calibration laboratories did to ensure that the CRM has metrologically traceable quantity values are all paid for in the certificate. 

Throughout product realization, the product identification and traceability are ensured using appropriate means. 

The identification and traceability is maintained to ensure product recall in the event of nonconformity or for rework. 

Documents received from external organizations are recorded to ensure traceability. 

Before the release system, all inspection and test operations are ensured to have been satisfactorily completed, and all documentary evidence is reviewed and completed with product identification and traceability. 

It is recommended that wherever possible the structure of the URS be used as the basis for the presentation format of the FDS and hardware and software design specifications this helps ensure design decisions are auditable back to the source requirement. Traceability should also be carried forward to the qualification test procedures, where it can link each test and qualification acceptance criterion directly to a specific requirement. 

To enable the supplier to demonstrate the correctness and completeness of the hardware design with the FDS To allow the pharmaceutical manufacturer to understand and compare the hardware design and traceability to the FDS To provide input to the hardware test specifications To ensure a structured approach to the presentation of information that can be carried forward into the hardware test specification... 

To allow the pharmaceutical manufacturer to ensure the correctness and completeness of the software implementation through traceability to the software design specification... 

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