A biopsy is the removal of tissue, blood, urine or other body fluids. Doctors order different types of tests depending on the types of information needed. Tissues are removed during surgery and must be tested for cancer. Blood and urine are tested for diagnostic purposes. Drug levels are monitored through laboratory tests. Doctors may order laboratory tests to detect and treat various diseases and conditions.
Hematological Blood Tests
Hematological tests are done directly on liquid whole blood. A machine is used to count and separate the different cells present. Measurements of oxygen carrying capacity are quantified. A single cell layer of blood is smeared on a microscope slide, stained and visually examined by a trained expert. Cells are examined for size, shape and condition. Abnormalities are reported to the doctor for diagnostic evaluation.
Coagulation Laboratory Tests
Heparin, Coumadin and other blood anticoagulants are measured by testing the time it takes blood to clot. Coagulation tests also detect bleeding disorders, like Von Willebrand's disease, hemophilia or other clotting factor deficiencies.
Chemical Blood, Urine and Body Fluid Tests
Many chemical analytes are present in blood, urine and body fluids. Cells are separated from the specimen by centrifugal force and the top fluid portion is analyzed by chemical, enzymatic or colorimetric measurements. Therapeutic drug levels also may be tested by a chemistry analyzer. Reference ranges tell the doctors if an analyte is normal or abnormal.
Microbiology Laboratory Tests
Swabs are taken of infected areas of the body and streaked on nutrient-rich growth plates that allow bacteria to grow. Analysis of the types, numbers and sensitivities of the bacteria tells a doctor which antibiotic to use. Samples of other body fluids can also be tested for bacterial growth.
Urine Laboratory Tests
Urine is considered to be a liquid biopsy of the kidney. Urine is tested for color, appearance, dissolved chemicals and cellular debris. A urinalysis tells the doctor the current functioning level of the kidneys. Other organs can spill chemical elements into the blood, which is filtered by the kidneys and may indicate other organ abnormalities.
Serological Laboratory Tests
Serological tests detect conditions, like HIV, rubella, mumps, and pregnancy. Special markers have been added to kits, which will react when the matching element is present.
Cytology, Histology and Pathology
Cytology is the microscopic study of cells removed from the body. A Pap smear is a typical cytological test for cancer of the cervix. Histology is the study of cells and chemical reactions. A pathologist specializes in directing and evaluating these types of tests.
Immunohematology and Blood Banking
Blood banking is used for the study of blood types and transfusion services. Samples of recipient blood are matched to donor blood in this type of laboratory test to determine compatibility of the blood for transfusion.