Body fluids such as blood contain many thousands of different substances. These include
materials such as:
Disease causes changes in the complex biochemistry of the body. These changes can often be detected by alterations in the concentration of substances in the blood - for example, glucose increases in diabetes mellitus; cretinine and urea increases in kidney disease. Some diseases, for example cancers and heart attacks, cause different substances to appear in the circulation. In some cases an abnormality in the biochemistry can result in desease, for example high cholesterol and cardiovascular disease. Clinical Biochemistry is concerned with changes in the composition of blood, and other body fluids, associated with diagnosis of disease and monitoring of therapy. It has a long history - Chinese and Egyptian physicians and scientists made observations on the changes in urine in certain diseases more than 2000 years ago. However, modern Clinical Biochemistry began around a hundred years ago, coupled with developments in organic chemistry and the beginnings of what we now call biochemistry.
Today's Clinical Biochemistry Department (usually based within a hospital) is responsible for providing rapid analytical results of high quality on samples from patients, interpreting the significance of the data obtained and advising on whether further investigations are needed. Most Departments will also carry out fundamental or applied research, and develop and investigate new methods of diagnosis and treatment. Many different disciplines interact with the Clinical Biochemist; including medicine, analytical chemistry, physiology, pharmacology, forensic science and molecular biology all play a part. The Clinical Biochemistry department of a District General Hospital will usually perform well over a million tests a year. Tests required in large numbers (such as sodium, glucose and urea in blood) are analysed on highly sophisticated automated equipment at rates of up to a thousand tests per hour. Other techniques used in clinical biochemistry include, absorption spectroscopy, electrophoresis, many types of chromatography, GC-MS and tandem MS, immunoassay and DNA technology.
As medicine becomes more complex, high calibre scientists are increasingly needed to maintain and extend the Clinical Biochemistry service, and to ensure that resources are used effectively. There are many opportunities to specialise in particular areas such as paediatric biochemistry, toxicology or endocrinology. The work is interesting, rewarding and extremely varied and its direct benefit to patients brings a particular satisfaction to scientists involved in health care.