International Federation of Clinical Chemistry and Laboratory Medicine

The properties of a pH electrode are characterized by parameters like linear response slope, response time, sensitivity, selectivity, reproducibility/accuracy, stability and biocompatibility. Most of these properties are related to each other, and an optimization process of sensor properties often leads to a compromised result. For the development of pH sensors for in-vivo measurements or implantable applications, both reproducibility and biocompatibility are crucial. Recommendations about using ion-selective electrodes for blood electrolyte analysis have been made by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) [37], IUPAC working party on pH has published IUPAC s recommendations on the definition, standards, and procedures... 

Table 2 Groups in the International Federation of Clinical Chemistry and Laboratory Medicine related to various elements of metrological traceability...

It is relevant to ask how often the routine measurement procedures currently used in laboratory medicine provide results that are traceable to high-level calibrators and reference measurement procedures (Lequin personal communication). It turns out that primary reference measurement procedures and primary calibrators are only available for about 30 types of quantity such as blood plasma concentration of bilirubins, cholesterols and sodium ion. International reference measurement procedures from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and corresponding certified reference material from BCR are available for the catalytic activity concentration of a few enzymes such as alkaline phosphatase and creatine kinase in plasma. For another 25 types of quantity, such... 

With the introduction of quality assurance in the diagnostic laboratory 56 years ago [6], a kind of educational and benchmarking process started forcing laboratories, national and international organizations, and the IVD industry to improve the methods applied in clinical laboratories. Comparison of the measurements of enzyme activity demonstrate that the analytical performance of the methods applied 30 years ago were far beyond the biological variation and most probably insufficient for medical needs. Interlaboratory comparisons show that with the new routine methods based on recommendations of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) (Table 5) comparable results can be obtained irrespective of time and space and thus small individual variations can now be detected. Similar improvements in the analytical process in clinical laboratories can be reported generally for homogenous measurands. 

Nevertheless, manufacturers are interested in the further development of reference materials and reference measurement procedures suited for application in human serum for medical purposes. Therefore, industry appreciates the efforts started by the Joint Committee of Trace-ability and Laboratory Medicine (JCTLM), an initiative supported by the Bureau International des Poids et Mesures (BIPM) and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) in order to develop suitable reference materials and measurement procedures, as well as to collect information on the activities of reference laboratories. In view of the limited resources and large efforts connected with these activities, clear priorities need to be set. Projects need to take into account the clinical importance of the analyte, consider the technical difficulties that must be overcome, and, most importantly, decide whether improvement of the metrological side is reflected in a gain of medically relevant information. 

Schumann G, Bonora R, Ceriotti F, Ferard G, Ferrero CA, et al. IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 C. International Federation of Clinical Chemistry and Laboratory Medicine. Part 4. Reference procedure for the measurement of catalytic concentration of alanine aminotransferase. Clin Chem Lab Med 2002 40 718-24. 

The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) recommends the term reference values and related terms, such as reference individual, reference limit, reference interval, and observed values. The definitions given below and the presentation in the following sections of this chapter are in accordance with the IFCC recommendations. ... 

The ATP produced is measured by hexokinase (HK)/ glucose-6-phosphate dehydrogenase (G6PD) coupled reactions that ultimately convert NADP to NADPH, which is monitored spectrophotometricaUy. Oliver first reported this method that RosaUd also described with the improvement of adding AMP to inhibit adenylate kinase (AK) and cysteine to activate CK. Subsequently, Szasz and colleagues optimized the assay by adding N-acetylcysteine to activate CK, EDTA to bind Ca and to increase the stability of the reaction mixture, and adenosine pentaphosphate (ApsA) in addition to AMP to inhibit AK. A reference method based on this previous experience was developed by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) it was modified recently to produce a reference procedure for the measurement of CK at 37 °C. ... 

Marcovina SM, Albers JJ, Scanu AM, Kennedy H, GiacuUi F, Berg K, et al. Use of a reference material proposed by the International Federation of Clinical Chemistry and Laboratory Medicine to evaluate analytical methods for the determination of plasma lipoprotein (a). Clin Chem 2000 46 1956-67. 

Tate JR, Berg K, Couderc R, Dati F, Kostner GM, Marcovina SM, et al. International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Standardization Project for the Measurement of Lipoprotein(a). Phase 2 selection and properties of a proposed secondary reference material for lipopro-tein(a). Chn Chem Lab Med 1999 37 949-58... 

Tonometry may be achieved by simple homemade assem-bhes or by cormnerdaUy available equipment. Some commercially available tonometers use a thin-film technique. It consists of a glass or plastic cup fitted on a shaft and enclosed in a humidified chamber whose temperature is maintained at 37 C. A few milliliters of blood is placed in the cup, and gas flow is initiated to continuously flush the inside surface of the cup with the humidified gas. A controller unit causes the cup to rotate rapidly and periodically in short bursts, so that the blood in the cup is thrown in a thin layer over the inside walls. Another form of tonometry is the bubble technique. It uses a syringe that is specially constructed to allow gas to be introduced and humidified through the plunger. During tonometry, the syringe is laid in a thermostatically controlled aluminum heat block. Additional detail on tonometry and its applications can be found in a previous edition of this textbook. Reference conditions for tonometry have been recommended by a committee of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). ... 

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