Blood Typing

Blood Typing

Blood Typing

Blood Typing

Blood typing is a test that determines a person’s blood type. The test is essential if you need a blood transfusion or are planning to donate blood. Not all blood types are compatible, so it’s important to know your blood group. Receiving blood that’s incompatible with your blood type could trigger a dangerous immune response.

The blood types

Your blood type is determined by what kind of antigens your red blood cells have on the surface. Antigens are substances that help your body differentiate between its own cells and foreign, potentially dangerous ones. If your body thinks a cell is foreign, it will set out to destroy it.

The ABO blood typing system groups your blood into one of four categories:

  • Type A has the A antigen.
  • Type B has the B antigen.
  • Type AB has both A and B antigens.
  • Type O has neither A nor B antigens.

If blood with antigens that you don’t have enters your system, your body will create antibodies against it. However, some people can still safely receive blood that isn’t their blood type. As long as the blood they receive doesn’t have any antigens that mark it as foreign, their bodies won’t attack it.

In other words, donations work as follows:

  • O: Type O individuals can donate blood to anyone, because their blood has no antigens. However, they can only receive blood from other type O individuals (because blood with any antigens is seen as foreign).
  • A: Type A individuals can donate to other type A individuals and type AB individuals. Type A individuals can receive blood only from other type A individuals and type O individuals.
  • B: Type B individuals can donate blood to other B individuals and AB individuals. Type B individuals can receive blood only from type B individuals and type O individuals.
  • AB: Type AB individuals can give blood only to other AB individuals, but can receive blood of any type.

Blood types are further organized by Rh factor:

  • Rh-positive: People with Rh-positive blood have Rh antigens on the surface of their red blood cells. People with Rh-positive blood can receive Rh-positive or Rh-negative blood.
  • Rh-negative: People with Rh-negative blood do not have Rh antigens. People with Rh-negative blood can receive only blood that is also Rh-negative.

Together, the ABO and Rh grouping systems yield your complete blood type. There are eight possible types: O-positive, O-negative, A-positive, A-negative, B-positive, B-negative, AB-positive, and AB-negative. While type O-negative has long been considered a universal donor, more recent research suggests that additional antibodies are sometimes present and may cause serious reactions during a transfusion.

Austrian Karl Landsteiner discovered blood types in 1901. Before that, blood transfusions were risky and potentially lethal. Landsteiner made the process much safer, and he was awarded the Nobel Prize for his work.

Why blood typing is done

Blood typing is done prior to a blood transfusion or when classifying a person’s blood for donation. Blood typing is a fast and easy way to ensure that you receive the right kind of blood during surgery or after an injury. If you’re given incompatible blood, it can lead to blood clumping, or agglutination, which can be fatal.

Blood typing is especially important for pregnant women. If the mother is Rh-negative and the father is Rh-positive, the child will likely be Rh-positive. In these cases, the mother needs to receive a drug called RhoGAM. This drug will keep her body from forming antibodies that may attack the baby’s blood cells if their blood becomes mixed, which often happens during pregnancy.

RISKS

You will need to have your blood drawn in order to have it typed. Having your blood drawn carries very minimal risks, including:

  • bleeding under the skin (hematoma)
  • fainting or feeling lightheaded
  • infection at the puncture site
  • excessive bleeding

PREPARATION

No special preparation is needed for blood typing. If you think you might feel faint during the test, you may want to have someone drive you home afterward.

How blood typing is performed

The blood draw can be performed at a hospital or a clinical laboratory. Your skin will be cleaned before the test with an antiseptic to help prevent infection. A nurse or technician will wrap a band around your arm to make your veins more visible. They will use a needle to draw several samples of blood from your arm or hand. After the draw, gauze and a bandage will be placed over the puncture site.

In order to determine your blood type, a lab technician will mix your blood sample with antibodies that attack types A and B blood to see how it reacts. If your blood cells clump together when mixed with antibodies against type A blood, for example, you have type B blood. Your blood sample will then be mixed with an anti-Rh serum. If your blood cells clump together in response to the anti-Rh serum, it means that you have Rh-positive blood.

After blood typing

Your blood type can be determined in a matter of minutes. Once you know your blood type, you can donate blood and receive transfusions from donors in the compatible blood groups.

Source: https://www.healthline.com/health/blood-typing#how-its-done



What is Blood?

Blood is a constantly circulating fluid providing the body with nutrition, oxygen, and waste removal. Blood is mostly liquid, with numerous cells and proteins suspended in it, making blood "thicker" than pure water. The average person has about 5 liters (more than a gallon) of blood.

About Blood Donation

A blood donation occurs when a person voluntarily has blood drawn and used for transfusions and/or made into biopharmaceutical medications by a process called fractionation (separation of whole-blood components). Donation may be of whole blood (WB), or of specific components directly (the latter called apheresis). Blood banks often participate in the collection process as well as the procedures that follow it.

More Facts

A liquid called plasma makes up about half of the content of blood. Plasma contains proteins that help blood to clot, transport substances through the blood, and perform other functions. Blood plasma also contains glucose and other dissolved nutrients.

About half of blood volume is composed of blood cells:

• Red blood cells, which carry oxygen to the tissues
• White blood cells, which fight infections
• Platelets, smaller cells that help blood to clot

Blood is conducted through blood vessels (arteries and veins). Blood is prevented from clotting in the blood vessels by their smoothness, and the finely tuned balance of clotting factors.

Blood Conditions

Hemorrhage (bleeding): Blood leaking out of blood vessels may be obvious, as from a wound penetrating the skin. Internal bleeding (such as into the intestines, or after a car accident) may not be immediately apparent.

Hematoma: A collection of blood inside the body tissues. Internal bleeding often causes a hematoma.

Leukemia: A form of blood cancer, in which white blood cells multiply abnormally and circulate through the blood. The abnormal white blood cells make getting sick from infections easier than normal.

Multiple myeloma: A form of blood cancer of plasma cells similar to leukemia. Anemia, kidney failure and high blood calcium levels are common in multiple myeloma.

Lymphoma: A form of blood cancer, in which white blood cells multiply abnormally inside lymph nodes and other tissues. The enlarging tissues, and disruption of blood's functions, can eventually cause organ failure.

Anemia: An abnormally low number of red blood cells in the blood. Fatigue and breathlessness can result, although anemia often causes no noticeable symptoms.

Hemolytic anemia: Anemia caused by rapid bursting of large numbers of red blood cells (hemolysis). An immune system malfunction is one cause.

Hemochromatosis: A disorder causing excessive levels of iron in the blood. The iron deposits in the liver, pancreas and other organs, causing liver problems and diabetes.

Sickle cell disease: A genetic condition in which red blood cells periodically lose their proper shape (appearing like sickles, rather than discs). The deformed blood cells deposit in tissues, causing pain and organ damage.

Bacteremia: Bacterial infection of the blood. Blood infections are serious, and often require hospitalization and continuous antibiotic infusion into the veins.

Malaria: Infection of red blood cells by Plasmodium, a parasite transmitted by mosquitos. Malaria causes episodic fevers, chills, and potentially organ damage.

Thrombocytopenia: Abnormally low numbers of platelets in the blood. Severe thrombocytopenia may lead to bleeding.

Leukopenia: Abnormally low numbers of white blood cells in the blood. Leukopenia can result in difficulty fighting infections.

Disseminated intravascular coagulation (DIC): An uncontrolled process of simultaneous bleeding and clotting in very small blood vessels. DIC usually results from severe infections or cancer.

Hemophilia: An inherited (genetic) deficiency of certain blood clotting proteins. Frequent or uncontrolled bleeding can result from hemophilia.

Hypercoaguable state: Numerous conditions can result in the blood being prone to clotting. A heart attack, stroke, or blood clots in the legs or lungs can result.

Polycythemia: Abnormally high numbers of red blood cells in the blood. Polycythemia can result from low blood oxygen levels, or may occur as a cancer-like condition.

Deep venous thrombosis (DVT): A blood clot in a deep vein, usually in the leg. DVTs are dangerous because they may become dislodged and travel to the lungs, causing a pulmonary embolism (PE).

Myocardial infarction (MI): Commonly called a heart attack, a myocardial infarction occurs when a sudden blood clot develops in one of the coronary arteries, which supply blood to the heart.

Source: WebMD

Today in the developed world, most blood donors are unpaid volunteers who donate blood for a community supply. In some countries, established supplies are limited and donors usually give blood when family or friends need a transfusion (directed donation). Many donors donate as an act of charity, but in countries that allow paid donation some donors are paid, and in some cases there are incentives other than money such as paid time off from work. Donors can also have blood drawn for their own future use (autologous donation). Donating is relatively safe, but some donors have bruising where the needle is inserted or may feel faint.

Potential donors are evaluated for anything that might make their blood unsafe to use. The screening includes testing for diseases that can be transmitted by a blood transfusion, including HIV and viral hepatitis. The donor must also answer questions about medical history and take a short physical examination to make sure the donation is not hazardous to his or her health. How often a donor can donate varies from days to months based on what component they donate and the laws of the country where the donation takes place. For example, in the United States, donors must wait eight weeks (56 days) between whole blood donations but only seven days between plateletpheresis donations and twice per seven-day period in plasmapheresis.

The amount of blood drawn and the methods vary. The collection can be done manually or with automated equipment that takes only specific components of the blood. Most of the components of blood used for transfusions have a short shelf life, and maintaining a constant supply is a persistent problem. This has led to some increased interest in autotransfusion, whereby a patient's blood is salvaged during surgery for continuous reinfusion—or alternatively, is "self-donated" prior to when it will be needed. (Generally, the notion of "donation" does not refer to giving to one's self, though in this context it has become somewhat acceptably idiomatic.)

Who can give blood

Most people can give blood. You can give blood if you:

  • are fit and healthy
  • weigh between 7 stone 12 lbs and 25 stone, or 50kg and 160kg
  • are aged between 17 and 66 (or 70 if you have given blood before)
  • are over 70 and have given blood in the last two years

How often can I give blood?

Men can give blood every 12 weeks and women can give blood every 16 weeks. Find out more about what happens on the day of your donation.

Check you are able to give blood

You can check some of the most common eligibility questions we receive from blood donors.

You can register here as a blood donor.

The common reasons donors should check if they can give blood are:

  • if you are receiving medical or hospital treatment
  • if you are taking medication
  • during and after pregnancy
  • if you feel ill
  • if you have cancer
  • after receiving blood, blood products or organs.

Women under 20 - check if you can give blood.

X