Have you ever had surgery and the doctors check your blood group even though you already know what it is?
Let us begin with a basic science lesson.
Blood is actually a mixture of water, chemicals and different cells. The red blood cells gives blood its unique colour and allows it to transport oxygen around the body.
Each red blood cell looks like a round pillow. There are many different types of tiny chemical proteins on the surface. One type gives us the ABO blood groups and another type gives us the Rh type. Different combinations give us eight different blood types O+, O-, A+, A-, B+, B-, AB+ and AB-. Why does the doctor check your blood group again? Is it because it may change? The reason is that if there is a mismatch, a deadly transfusion reaction may occur. The difference between a simple + and - could literally be life and death.
During medical emergencies, O- blood is given as it is considered the universal donor.
If you have further questions about your blood group, please speak to your doctor.