Reference materials quality

The establishment of performance criteria for a given tumor marker test is not a simple process because accuracy and precision are unique for each type of analyte and its application. Establishing methodological limits for accuracy, precision, sensitivity, and specificity often requires standard reference materials, quality control materials, comparative studies, and actual clinical specimens. Accuracy and precision must be measured over the analyte reportable range for which the device is intended to be used. Sensitivity and specificity must be considered with respect to the intended clinical use of the device. Also, the indications for use should be carefully considered in the design of the study protocol. The indications for class II should be to monitor residual tumor after surgery (or radiation), the recurrence of tumor, or response to therapy. A 510(k) must provide clear evidence that the device is accurate, safe, effective, and substantially equivalent to a device legally marketed in the United States. 

Keywords Traceability Measurement uncertainty Reference materials Quality of analytical results... 

There will be a continued need for enantiospecific methods of preparation and analysis, not only to ensure the quality of the final drug substance and reference materials, but also to control starting materials used for their manufacture, and key intermediates during synthesis. Likewise, specific and sensitive bioanalytical methods will be required to follow the fate of individual enantiomers after their administration. 

The students strongly approve of using current press accounts of global change issues, both scientific and policy related, in parallel with basic reference material. Some advised that future classes should require subscription to a high quality newspaper or journal, in addition to purchase of basic texts, for example one of those that were used in class. 

In medicine the need for standards was just as acute. Beal (r95i) mentioned that the U.S. Pharmacopoeia VI, issued in 1880, took a big step forward by adding tests for purity and quality of the materials described in it, but the use of reference materials as an integral part of the pharmaceutical monographs for drugs did not start until the 1950 s. Another example of activities at the end of the 19th Century was associated with the introduction, by Ehrlich, of the first diphtheria antitoxin and his... 

In addition to the requirements regarding traceability of measurement results, the measurement methods employed should represent "state-of-the-art in the particular field. Failing to do so would lead to a reference material with an uncertainty that has become too large to serve as a quality control. The better the methods perform in terms of uncertainty and traceability, the better the reference material will serve the interests of the (potential) users. 

Chau ASY, Caeron J and Lee H-B (1979) Analytical reference materials. II. Preparation and sample integrity of homogeneous fortified wet sediment for polychlorinated hiphenyl quality control studies. J Assoc Off Anal Chem 62 1312-1314. 

Griepink B, Maier EA, Quevauvilier P and Muntau H (1991) Certified reference materials for the quality control of analysis in the environment. Fresenius Anal Chem 339 599-603. 

ISO Guide 34 (1996) Quality system guidehnes for the production of reference materials. (Revised March 1998 as ISO/REMCO document No 464 General requirements for the competence of reference material producers . The revised Guide 34 will appear early 2000.) International Organization for Standardization, Geneva. 

Muntau H (1980) Measurement quality improvements by application of reference materials. In Brattee P and Schramel P, eds. Trace Element Analytical Chemistry in Medicine and Biol-ogy, PP707-726. Walter de Gruyter Co Berlin New York. 

Analytical Quality Control Services (1998) AQCS Intercomparison Runs Reference Materials 1998-1999. International Atomic Energy Agency, Vienna. 

Becker DA (1993) Unique quality assurance aspects of INAA for reference material homogeneity and certification. Fresenius J Anal Chem 345 298-301. 

Benoliel MJ. Quevauviller P, Rodrigues E, Andrade ME, Cavaco MA, Cortez L (1997) Certification of reference materials for quality control of major element determinations in ground-water Part i Feasibility study, fresenius J Anal Chem 358 574-580. 

Ihnat M (1988c) Biological reference materials for quality control. In McKenzie HA, Smythe LE, eds. Quantitative Trace Analysis of Biological Materials, pp 331-351. Elsevier Science Publishers, Amsterdam. 

Ihnat M (1994) Development of a new series of agricultural/food reference materials for analytical quality control of elemental determinations. J AOAC Inti 77 1605-1627. 

Jenks P, Boekholt a, Maaskant J, Rucinski R (1998) Are Certified Reference Materials a victim of Quality Systems Fresenius J Anal Chem 360 366-369... 

Morabito R, Muntau H, Cofino W, Quevauviller Ph 1999) A new mussel certified reference material (CRM 477) for the quality control of butyltin determination in the marine environment. J Environ Monit 1 75-82. 

Quevauviller Ph, Kramer KJM, Vinhas T (1996) Certified reference material for the quality control of cadmium, copper, nickel and zinc determination in estuarine water (CRM 505). Fresenius J Anal Chem 354 397-404. 

Quevauviller Ph, Maier EA, Vercoutere K, Muntau H, Griepink B (1992a) Certified reference material (CRM 397) for the quality control of trace element analysis of human hair. Fresenius J Anal Chem 343 335-338. 

Quevauviller Ph, Vercoutere K, Griepink B (1992b) Certified reference materials (CRMs 398 and 399) for the quality control of major element determination in freshwater. Mikrochim Acta 108 195-204. 

Zeisler R, Wise SA (1985) Quality assurance and protocols in sampling and sample preparation of biological samples. In Wolf WR, ed. Biological Reference Materials Availability, Uses and Need for Validation of Nutrient Measurement, pp. 257-279. John Wiley and Sons, New York. 

For the high accuracy needed in the quantitative measmement of the species, quality assurance of the analytical procedures is of prime importance. This can only be achieved by using representative RMs, certified for the relevant species. Up to now the number of existing certified reference materials is very limited. This section will give a survey of the main species that are presently determined routinely or for research purposes. 

Byrne AR, and Kucera J (1997) Role of the self-validation principle of NAA in the quality assurance of bioenvironmental studies and in the certification of reference materials. Proc. Int. Symp. Harmonization of Health Related Environmental Measurements Using Nuclear and Isotopic Techniques, Hyderabad, India, pp 223-238. IAEA Vienna. 

Ihnat M (1993) Reference materials for data quality. In Carter MR, ed. Soil Sampling and Methods of Analysis, Chap. 26, pp 247-262. Lewis Publishers, Boca Raton, FL. 

ISO (1996) Quality System Guidelines for the Production of Reference Materials, Guide 34 i996E. International Organization for Standardization, Geneva. 

Quevauviller Ph, Herzig R. and Muntau H (1996b) Certified reference material of lichen (CRM 482) for the quality control of trace element biomonitoring. Sci Total Environ 187 143-152 Quevauviller Ph, Lachica M., Barahona E, Rauret G, Ure A, Gomez A, and Muntau H (1997) The certification of the EDTA-extractable contents (mass fractions) of Cd, Cr, Ni, Pb, and Zn and of the DTPA-extractable contents (mass fractions) of Cd and Ni in calcareous soil by the extraction procedures given CRM 600. EUR Report 17555 Quevauviller Ph. Maier EA, and Griepink B, eds. (1995) Quality Assurance for Environmental Analysis. Elsevier. Amsterdam. 

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