The newcomer to the field of clinical chemistry is faced with the daunting prospect of understanding the ever increasing aspects of the subject: new techniques, tests, terminology, methods of diagnosing diseases and other advances which relate to clinical chemistry. The aim of this book is to provide basic information regarding all branches of the subject which the trainee will need to understand. The book should also provide a basis for answering many of the examination questions of clinical chemistry. It is therefore hoped that this book will prove useful to any person starting a career in clinical chemistry, be that person a laboratory scientific officer, graduate or trainee pathologist. Wherever possible, suggestions for further reading are given. Many subjects are so broad however that the reader is referred to the general list of analytical and clinical textbooks supplied at the end of the book. My grateful thanks are extended to the three ladies who typed this manuscript: Christine Cliffe, Margaret Donnelly and Judith Hardy. I would like to thank Dr Brian Wisdom of Queens University, Belfast for his suggestions on the entry "Enzyme-immunoassay". Finally my thanks go to Mr Martin Lister of MTP Press for his help and encouragement in this venture. W. H. ASHTON-UNDER-L YNE APRIL 1980 vii A ABETALIPOPROTEINAEMIA A rare hereditary disorder in which there is a complete absence of j3-lipoprotein, pre:f3-1ipoprotein and chylomicrons. It presents clinically as ataxia and malabsorption with steatorrhoea. Thorny shaped erythrocytes (acanthocytes) are a feature of the disease.