Do you have a rare blood group? Then, you need to be more equipped than the average person to handle a medical emergency requiring blood transfusion. Since rare blood groups occur in less than one in a 1,000 people, the donation of blood of a rare group, and consequently, its supply, could be that much scarcer. Blood banks may also not have adequate volumes of blood of rare groups.
So, what happens when there is a mismatch in blood groups? “Back pain, vomiting and chest pain are the symptoms that show up when a blood transfusion is mismatched. It can end in death too,” says A. Karthikeyan, senior consultant haematologist, Fortis Malar.
The ABO system is the most important grouping system for human blood. Next is the Rh system. Apart from this, there are scores of other blood typing systems such as the Bombay blood group, Kell, Duffy, and Kidd blood types (positive or negative). In fact, many more new systems are being identified all the time.
Who is at risk?
“In the ABO system, AB -ve, B -ve and A -ve are rare. And, since 90 per cent of our population is Rh positive (their blood carries the Rh antigen), the Rh -ve blood type is rare. Besides the ABO and Rh systems, the rare blood system that is most clinically relevant for the Indian population is the Bombay blood group, wherein the red cells in the blood lack the H antigen normally present in others,” informs P. Prabu, consultant haemato-oncologist, Apollo Hospitals.
The Bombay group occurs in one in 10,000 persons, according to rough estimates, and is more common in Western and South India. Blood bank physicians and technicians must also be alert for special blood types. For instance, if blood grouping is not done properly, the Bombay blood group may not get detected. Reverse grouping or Serum grouping has to be performed to detect the Bombay blood group.
Besides people with rare blood groups, those who undergo repeated blood transfusions are at high risk and need to have extended typing of blood. So do those with thalassemia, chronic haematological conditions, chronic anaemia, sickle cell anaemia, and pregnant women.
“If you keep exposing yourself to new antigens from repeated transfusions, your blood becomes increasingly sensitive and produces antibodies to the new antigens. So, a few years down the line, finding compatible blood might become difficult,” says Dr. Prabu.
Then, there is the issue of childbirth and Rh incompatibility. If the foetus in the womb is Rh +ve, and if the mother happens to be Rh -ve, during any intervention during pregnancy and childbirth, a little of the foetal blood may come into the mother's circulation and cause formation of Rh antibodies in the mother's blood. “In a future pregnancy, these antibodies may attack the new foetus (if it is Rh +ve) and cause haemolytic diseases of the newborn, jaundice, anaemia and even fatality,” warns Dr. Prabu.
Preparing for an emergency
Being part of a blood donation network is an important way of preparing for an emergency — so, if you have a rare blood group, donate often. That way, you help create enough stores of that particular blood group.
“A person weighing over 50 kg can safely donate about 350 ml of blood, once every 90 days (for whole blood) and once in two weeks (for platelets),” informs Sai Babu, haematologist and senior consultant, blood bank, Frontier Lifeline.
Your blood of rare group could give a lease of life to someone. And someday, you may need it yourself.
LIFE SAVERS
If anyone in the family is known to have a rare blood type, get your blood checked for that group
Maintain a network of people with the same blood type from whom you can get blood during an emergency. Register yourself in rare blood group registries such as rarebloodgroups.org
Mention your ethnic group in the blood donation registration card; this would save time when the blood bank has to locate the rare blood type common in that ethnic group
Keep the numbers of reliable blood banks handy
If you are going to have a surgery, check if your hospital has stores of your blood type, and also keep in touch with potential blood donors
Autologous blood transfusion (storing your own blood for emergency use) can be considered for a planned surgery
