Clinical biochemical determinations reliability

The editors sincerely hope that this book will, with its introduction into the basic principles and limitations of the presently available trace analytical methodology and its detailed description of reliable procedures and quality control measures, serve as a valuable aid for all those who are involved in trace element analysis. It should be especially beneficial for analysts and researchers in clinical chemistry, toxicology, biochemical and environmental research first as a general overview and second to serve as a collection of elaborated methods for the reliable determination of the above-mentioned elements and some of their species in selected (human) biological specimens. 

Because treatment is most effective if started in earliest infancy, it is necessary to make the diagnosis of phenylketonuria before any clinical signs appear, i.e. from the biochemical changes. Every newborn infant must be tested and, therefore, the test used must be inexpensive, simple and reliable [70, 71]. The available methods are determination of phenylalanine concentration in the blood, o-hydroxyphenyl-acetic acid in urine or phenylpyruvic acid in urine. The third method, once widely used, has now been largely abandoned the first and, to a lesser extent, the second are used on a very large scale in many countries. Sometimes tests for other conditions, such as homocystinuria, galactosaemia and maple syrup urine disease, are combined with the test for phenylketonuria. 

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