It is important to know your blood type, especially if you have frequent transfusions or want to have a baby. The AB0 classification system identifies the various groups with the letters A, B, AB or with the number 0. Another classification factor is the one called Rh factor, or Rhesus, which can be positive or negative. Blood type and Rh factor are passed on from parents to children. To find your Rh factor, you need to know your parents' or you can have a blood test at your doctor's office.
Steps
Part 1 of 2: Using Known Information to Determine the Rh Factor
Step 1. Understand what this factor indicates
It is a protein found in red blood cells, which may or may not be inherited from parents. If your blood group is "Rh positive", it means you have this protein; if this is absent, the group is "Rh negative".
- People with positive factor have positive blood groups: A +, B +, AB + or 0+; individuals with a negative factor have negative blood groups: A-, B-, AB- or 0-.
- Most people have the Rh protein.
Step 2. Consult your medical record
Chances are you've already had blood tests and your Rh factor has already been determined. Ask your family doctor if he has the data relating to your blood type. If you have regular transfusions, this information is most likely on your medical file; the same is true if you are a blood donor.
If you have a positive Rh factor, you can receive both Rh + and Rh- blood during a transfusion. If your factor is Rh-, you can only receive blood that does not contain the protein, except in the rare cases of extraordinary emergency, where you may also need a transfusion with Rh +
Step 3. Identify your parents' Rh factors
Ask them if they have a positive or negative blood type - you may be able to determine yours from this data. If both are Rh-, chances are you don't have the protein too. If your mother has a negative blood type and your father has a positive (or vice versa), you could be both Rh + and Rh-. In this case, you can have a definitive answer by having a blood test at your doctor's office or blood transfusion center. Note that you may have a negative factor even if your parents are both Rh +.
Since people with positive blood types can have two Rh positive (Rh + / Rh +) genes or one positive and one negative (Rh + / Rh-), they can produce Rh- factor offspring
Part 2 of 2: Undergo a blood test
Step 1. Ask your doctor to test
If your parents have different Rh factors (or they are both positive and you want to know if you are too), you can ask your doctor for a test. This is a quick outpatient procedure, which shouldn't cause much pain and you can go home afterwards.
Step 2. Get a blood test
A nurse or doctor wipes the inside of your elbow or wrist with antiseptic gauze. easily locates an accessible vein and inserts a needle into it which is usually attached to a syringe, which in turn draws blood. When the operator has collected a sufficient quantity of it, he removes the needle and exerts a gentle pressure on the sampling site with a sterile swab; then apply a patch. At the end of the procedure the nurse places a label on the sample and sends it to the laboratory for analysis.
- The doctor takes the sample on children by puncturing a vein on the back of their hands.
- If you feel like you are going to faint, let your healthcare provider know to help you lie down.
- You may feel the sensation of a sting or a slight pain when the needle is inserted. A small bruise may also develop at the sampling site; in any case, the pain does not last long.
Step 3. Wait for the test results
A lab technician examines the blood sample to look for the Rh protein. It proceeds by mixing the blood with an anti-Rh serum; if the blood cells clot, the Rh factor is positive; if, on the other hand, the cells do not join together, the factor is negative.
The laboratory is also likely to perform tests to determine the blood group based on the AB0 classification
Step 4. Recognize the importance of outcomes
Write down your blood group information in a safe place along with your emergency contacts. If you need a transfusion or a transplant someday, you will need this data; also, if you are a woman and are planning to have a baby, it is essential to know the Rh factor.
Step 5. Be aware of the risks of pregnancy
If you are a woman with Rh-, your partner must be tested to know hers; if the possible future father is Rh +, an incompatibility could develop. This means that if the fetus inherits the positive factor from the father, its red blood cells are attacked by the maternal antibodies; this event causes severe anemia and even death of the fetus.
- During pregnancy, if you are Rh- you need to have blood tests to see if your body is making antibodies to the Rh + factor. The first test is performed during the first trimester and the second during the 28th week of pregnancy. If there are no antibodies, an injection of Rh immunoglobulin is given to prevent the body from producing antibodies that are harmful to the baby.
- If tests reveal the presence of antibodies, no injection is given, but the doctor closely monitors the fetus as it develops; the baby may have a transfusion before or after birth.
- After delivery, the doctor tests the newborn for Rh factor. If the results confirm that it is identical to that of the mother, the baby does not need further care; however, if her Rh is positive and her mother's is negative, she is given another injection of immunoglobulin.
