Clinical biochemistry is associated with helping to diagnose and manage disease through the qualitative and quantitative analysis of biological fluids such as blood, serum or plasma, and urine, for specific chemical constituents or physiologic processes. The analysis is performed by the use of a wide range of equipement from the simple basic to automated, modern and sophisticated systems. Physicians can then use these test results to screen for, diagnose or monitor disease.
Clinical chemistry is a quantitative science that is concerned with measurement of amounts of biologically important substances (called analytes) in body fluids. The methods to measure these substances are carefully designed to provide accurate assessments of their concentration.
The results of clinical chemistry tests are compared to reference intervals or a medical decision level (MDL) to provide diagnostic and clinical meaning for the values.
The tests in a clinical chemistry laboratory measure concentrations of biologically important ions (sodium, potassium, chloride, and calcium), small organic molecules (glucose, cholesterol, triglycerides, urea, creatinine, bilirubin) and large macromolecules (albumin, transferrin, ferritin, total proteins, amylase). When an individual test alone is not sufficient to assess a medical condition, a combination of several tests may be used.
The pattern of results from the combination of tests may provide better insight into the status of the patient than any single test result. Such tests, done on the same sample, are often ordered as a group called a panel or profile. (Electrolyte panel, hepatic panel or liver profile, lipid profile).
Some examples of biochemistry tests are:
Glucose levels indicate the body’s efficiency in metabolizing glucose. Fasting and random glucose levels in blood help in the diagnosis of endocrinological disorders such as hypoglycemia (low blood sugar) and diabetes.
Lipids are present in different forms as body fat, as part of cell membranes, and as sterols such as cholesterol. Lipid levels can help diagnose liver and heart disease in humans. For example, high levels of total cholesterol and triglycerides in blood are a risk factor for cardiovascular disease (CVD). High-density lipoprotein (HDL) is a good form of cholesterol which offers protection from heart disease whereas low-density lipoprotein (LDL) is a harmful form which is another risk factor for CVD.
Measuring the levels of enzymes released by organs into the blood can indicate problems with the particular organ. For example, levels of the enzyme creatine kinase in the body indicate heart or skeletal muscle damage, alanine aminotransferase or aspartate aminotransferase levels can help diagnose liver disorders, and amylase and lipase levels signal pancreas inflammation or pancreatic carcinoma.
The concentration of proteins in the body can be indicative of nutritional and metabolic disorders. For example, total protein and albumin levels help diagnose liver or kidney disease in addition to malnutrition. Globulin levels and the ratio of albumin to globulin can help detect infection, inflammation, autoimmune disease, and some forms of blood cancer.
The levels of various electrolytes such as sodium, chloride, potassium, calcium, bicarbonate, phosphorus, and magnesium in the body can help diagnose some kidney and metabolic disorders.
Some metabolic products can be measured to assess the functioning of certain organs. For example, levels of urea, nitrogen and creatinine in the blood are indicators of kidney function. Similarly, uric acid levels can signal kidney disease, gout, and damage to other tissues.