Book excerpt: This forth updated edition contains the latest developments in analytical techniques. An international team of authors summarizes the information on biological influences, analytical interferences and on the variables affecting the collection, transport and storage as well as preparation of samples. They cover age, gender, race, pregnancy, diet, exercise and altitude, plus the effects of stimulants and drugs. National and international standards are described for sampling procedures, transport, sample identification and all safety aspects, while quality assurance procedures are shown for total laboratory management. In addition, the authors provide a glossary as well as a separate list of analytes containing the available data on reference intervals, biological half-life times, stability and influence and interference factors. For everyone involved in patient care and using or performing laboratory tests.