A blood screening is a medical process in which blood is scanned to test for a particular disease or condition. Although this procedure may be done for variety of reasons, the most common include human immunodeficiency (HIV) screenings, pregnancy screenings, and blood type screenings. Screening blood may also be needed to check for things like general infections and cancer. Additionally, all blood is carefully screened for serious diseases like HIV when it is donated to a blood bank.
Before the screening takes place, the patient is generally required to visit a doctor’s office or hospital in order to have blood drawn. This is done by inserting a needle into the patient’s arm, generally in the crease of the elbow. The needle is attached to a vial which is used to collect the blood, and can be removed if more than one vial is needed in order to do multiple screenings. Most of the time, the patient only has to have the needle inserted once.
An HIV blood screening is used to detect the presence of the virus which causes AIDS. HIV screenings are generally fairly accurate, although it can take anywhere from three months to one year after exposure before the virus can be detected in some individuals. Those who test positive will likely be screened a second time to ensure that the results are accurate. If a test comes back positive a again, the patient will be notified and treatment can begin.
There are also different types of screenings that can be done to detect fetal abnormalities during pregnancy, as well as to check for issues in the mother. Certain chemicals or hormones may be released into the blood if the fetus has certain defects. Mothers may also have a blood screening to check human chorionic gonadotropin (hCG) levels within the blood as well as her blood type to ensure that it matches that of her baby if she is Rh-negative.
Conditions like infections and cancer may also be initially detected through a blood screening. If there is a body wide infection, then the blood will likely show high levels of white blood cells. These are the body’s first line of defense against invading bacteria and viruses, and they can be found in large numbers when an infection has spread throughout the body. Cancer may also lead to a sharp increase or decline, primarily in cancers which affect the blood, bone marrow, or lymph nodes.
In some rare cases, a blood screening may be tainted due to contaminated utensils, and results may be inaccurate. For this reason, second blood tests along with other screening tools will likely be used in the even that a disease or condition is found during the initial test. Most blood screenings can only test for one thing at a time. This means that conditions like HIV will not be found during routine blood tests.