Blood, Blood groups & Blood types.

Blood is a bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. When it reaches the lungs, gas exchange occurs when carbon dioxide is diffused out of the blood into the alveoli and oxygen is diffused into the blood. This oxygenated blood is pumped to the left hand side of the heart in the pulmonary vein and enters the left atrium. From here it passes through the bicuspid valve, through the ventricle and taken all around the body by the aorta. Blood contains antibodies, nutrients, oxygen and lots more to help the body work.

In vertebrates, it is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume),[1] and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cells themselves. Albumin is the main protein in plasma, and it functions to regulate the colloidal osmotic pressure of blood. The blood cells are mainly red blood cells (also called RBCs or erythrocytes) and white blood cells, including leukocytes and platelets. The most abundant cells in vertebrate blood are red blood cells. These contain hemoglobin, an iron-containing protein, which facilitates oxygen transport by reversibly binding to this respiratory gas and greatly increasing its solubility in blood. In contrast, carbon dioxide is almost entirely transported extracellularly dissolved in plasma as bicarbonate ion.

Vertebrate blood is bright red when its hemoglobin is oxygenated. Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Arthropods, using hemolymph, have hemocytes as part of their immune system. Blood is circulated around the body through blood vessels by the pumping action of the heart.

Medical terms related to blood often begin with hemo- or hemato- (also spelled haemo- and haemato-) from the Greek word αîμα (haima) for "blood". In terms of anatomy and histology, blood is considered a specialized form of connective tissue, given its origin in the bones and the presence of potential molecular fibers in the form of fibrinogen.

Blood Groups

Thirty-three major blood group systems (including the AB and Rh systems) were recognised by the International Society of Blood Transfusion (ISBT) in October 2012.[1] In addition to the ABO antigens and Rhesus antigens, many other antigens are expressed on the red blood cell surface membrane. For example, an individual can be AB RhD positive, and at the same time M and N positive (MNS system), K positive (Kell system), and Lea or Leb positive (Lewis system). Many of the blood group systems were named after the patients in whom the corresponding antibodies were initially encountered.

The ISBT definition of a blood group system is where one or more antigens are "controlled at a single gene locus or by two or more very closely linked homologous genes with little or no observable recombination between them".

Blood grouping postulates

Blood is composed of cells suspended in a liquid-like substance called plasma. Suspended in the plasma are three types of cells:

The most common type of grouping is the ABO (either uppercase or lowercase) grouping. The varieties of glycoprotein coating on red blood cells divides blood into four groups:

  • A (A oligosaccharide is present)
  • B (B oligosaccharide is present)
  • AB (A and B oligosaccharides are present)
  • O (neither A nor B, only their precursor H oligosaccharide present)

There are subtypes under this grouping (listed as A1, A2, A1B or A2B…) some of which are quite rare. Apart from this there is a protein which plays an important part in the grouping of blood. This is called the Rh factor. If this is present, the particular blood type is called positive. If it is absent, it is called negative. Thus we have the following broad categories:

  • A1 Negative (A1 -ve)
  • A1 Positive (A1 +ve)
  • A1B Negative (A1B -ve)
  • A1B Positive (A1B +ve)
  • A2 Negative (A2 -ve)
  • A2 Positive (A2 +ve)
  • A2B Negative (A2B -ve)
  • A2B Positive (A2B +ve)
  • B Negative (B -ve)
  • B Positive (B +ve)
  • B1 Positive (B1 +ve)
  • O Negative (O -ve)
  • O Positive (O +ve)

Rare blood types

In the "ABO" system, (and Rhesus D system) all blood belongs to one of four major groups: A+/-, B+/-, AB+/-, or O+/-. The presence (+) or absence (-) of the RhD (Rhesus D) antigen is indicated by the plus or minus following the ABO type. But there are more than two hundred minor blood groups that can complicate blood transfusions. These are known as rare blood types. Whereas common blood types are expressed in a letter or two, which maybe a plus or a minus, a smaller number of people express their blood type in an extensive series of letters in addition to their 'AB-' type designation.

What is Blood Donation?

Blood is life and it’s an amazing fluid which keeps us alive. It’s the amazing gift we give to others to help them heal and live. Each and every day, patients in local hospitals served by BloodCenter of the town need several units of blood. You may not always see their faces, but the adults and children you help with your gift of blood are very real.

Blood donation is a voluntary procedure. You agree to have blood drawn so that it can be given to someone who needs a blood transfusion. Millions of people need blood transfusions each year. Some may need blood during surgery. Others depend on it after an accident or because they have a disease that requires blood components. Blood donation makes all of this possible.

Health screening

First you might be called for health screening, where a donor career confirms your identity. S/he must ensure that it's safe for you to donate and your donation is safe for a patient to receive. S/he asks some confidential questions based on your completed Donor Health Check. There is a period of time from contact with any infection to detecting markers in the laboratory. S/he trust your honesty when answering these personal questions. This will ensure your blood is safe to transfuse to patients.

You may be referred to a registered nurse for certain medical queries. An explanation will always be provided if you are not able to donate. You will be advised when you can donate, and she’ll encourage you to make an appointment before you leave. For your well being, she must ensure you have enough haemoglobin (iron) in your blood before donating. A small blood sample will be taken from your finger to test your haemoglobin levels. If your test is borderline, she will offer you a confirmatory test. This requires a sample of blood from your arm, to be tested in a machine at the session. She will advise you of the result.

Following health screening, you will be asked to sit in a different waiting area. From here you’ll be called and escorted to a donation chair.

Your Donation

When you are comfortable on the chair, you will be asked your name, address and date of birth again. Blood bags and sample tubes are labelled with unique donor identification numbers. All collection equipment is single use and sterile; only one blood bag is filled with your donation.

A blood pressure cuff will be placed on your arm to maintain a small amount of pressure during your donation. The cuff is not used to measure blood pressure. Your arm will be thoroughly examined to find a suitable vein before being cleaned with an antiseptic sponge. This kills normal bacteria (germs) on the skin. You will see staff cleaning their hands frequently, using hand wipes or gels.

Donors are advised to do applied muscle tension exercises during donation. This is to maintain blood pressure and promote well being during and after donation. Following needle insertion you should be comfortable during your donation. If you experience any discomfort or pain please alert a member of staff.

An agitator scale constantly weighs and measures your donation. It will stop automatically when your donation is complete. Donor carers will be available to you throughout your donation. You may hear beeping noises from the agitator, these inform us of the progress of your donation. A full donation is 470ml and will usually take between 5 and 10 minutes. If you require assistance or have any concerns, please make us aware by raising your non-donation arm.

After donation, the needle will be removed and a sterile dressing applied to your arm. We advise that you leave the pressure roll on for 30 minutes and the plaster dressing on for six hours. Please avoid using this arm to push on or to carry anything heavy. We will give you a card at the end of your donation with important care advice.

Advantages/Disadvantages of Blood Donation

  1. Balance Iron Levels in your blood

    For each unit of blood donated, you lose about one-quarter of a gram of iron.

    You may at first think this is a bad thing, since too little iron may lead to fatigue, decreased immunity, or iron-deficiency anemia, which can be serious if left untreated. This is common in children and premenopausal women.

    But what many people fail to realize is that too much iron can be worse, and is actually far more common than iron deficiency (especially in men and postmenopausal women).

    So for many, the fact that donating blood helps to rid your body of excess iron is one of the greatest benefits it offers. It has been long known that menstruating women have fewer heart attacks. This was previously thought to be due to hormones but is now thought to be due to lower iron levels.

    Interestingly, in a study published in the April 2013 issue of American Journal of Public Health, 4 researchers found that statin chliesterli-lowering drugs improved cardiovascular outcomes at least partially by countering the pro-inflammatory effects of excess iron stores.

    In this study, the improved outcomes were associated with lower ferritin (iron) levels but not with “improved” lipid status. Researchers concluded iron reduction might be a safe and low-cost alternative to statins, and according to logic this means that donating your blood, which reduces iron, could potentially help too.

  2. Better Blood Flow

    Do you know what a high-sugar diet, smoking, radio frequencies, and other toxic electromagnetic forces, emotional stress, anxiety, high cholesterol, and high uric acid levels do to your blood?

    All of these make your blood hypercoagulable, meaning it makes it thick and slow moving, which increases your risk of having a blood clot or stroke. Hypercoagulable blood contributes to inflammation, because when your blood does not flow well, oxygen can't get to your tissues.

    For example, early (and some current) birth control pills were notorious for causing heart attacks in women. One of the mechanisms that cause this increased risk is that synthetic estrogens and progesterones increase blood viscosity.

    Repeated blood donations may help your blood to flow better, possibly helping to limit damage to the lining of your blood vessels, which should result in fewer arterial blockages. (Grounding can also help to thin dangerously thick blood.) Phillip DeChristopher, M.D., Ph.D., director of the Loyola University Health System blood bank, told TIME:

    “What is clear is that blood donors seem to not be hospitalized so often and if they are, they have shorter lengths of stay… And they’re less likely to get heart attacks, strokes, and cancers.”

  3. Burns Calories

    One time blood donation helps you shed 650 Kcal. This can aid you in your body weight control measures. However, blood can be donated safely once in two or three months and not more frequently. This will depend on your health status and your blood hemoglobin and iron levels.

  4. Reduces Risk of Heart Disease

    Regular blood donations help to keep the levels of iron in the body in check, especially in males. This has shown to reduce heart disease. Though iron is an essential element for the proper functioning of the body, excessive iron buildup can result in excessive oxidative damage. Oxidative damage is the major culprit implicated in accelerated ageing, heart attacks, strokes etc. You can read more of the scientific information on the American Journal of Epidemiology.

  5. Reduces Risk of Cancer

    High levels of iron have been implicated in cancer. Theoretically, donating blood frequently will reduce the risk of cancers. More research is going on to find strong evidence on this one. However, the old myth that blood donations may lead to cancer has been put to the grave.

  6. The Joy of Saving Human Lives

    It is such a wonderful feeling being able to help doctors save human lives. There are no perfect substitutes for human blood. The blood you donate is divided into various components according to the needs of patients. Each component can be used by different recipients for various purposes. Many newborn babies may benefit from a single blood donor as their blood requirements are smaller. Every time you donate blood, you can help up to 3 or 4 individual recipients. Be a hero by donating blood.

  7. Free Health Check-up

    You can donate blood only if you are fit enough to do so. Before every blood donation process, a series of health check-ups are performed on the donor totally free of cost. This will be of great benefit to you. For example, you will come to know of any blood pressure abnormalities. That will help diagnose some of the indolent diseases at the early stage before they get flared up and present with multiple medical problems. Further, after the blood is donated, the blood and blood products that are derived from them are screened for certain infections. You can choose to be informed if they find any abnormality in those screening tests. Frequent blood donations are good free health check-ups that will help you stay healthy. Here is an interesting story of how blood donation saved a grandmother’s life.


There is no direct disadvantages but while giving blood donation you should keep some point in your mind like:

  1. The needle and bag should be sterilized, do not give blood more than 350ml at a time.
  2. Do not get up suddenly from the bed after giving blood.
  3. Also keep 3 month duration gap between each blood donating.
  4. After donating blood just take a glass of Glucose water take rest for five minute and after 30 minute you will feel as normal and you can do all your normal work.

Some people have fear to donate blood but there is nothing to fear just start donating blood once and see the happiness you bring for yourself as well as the person who get your blood. Also the health benefit to you like you stay away from some disease by just donating blood on regular basis.

Myths related to blood donation

One of the things that keeps many from donating blood is a misunderstanding about their eligibility. In truth, there are very few things that may prevent a healthy person from donating blood. Here are some of the common myths and truths about blood donation:

Myth 10 - I can't give blood because I have seasonal allergies.
Allergies, even those that need to be controlled by medication, will not prevent you from donating blood as long as symptoms are mild and you are generally feeling well.

Myth 9 - I can't give blood because I have high blood pressure.
As long as your blood pressure is below 180 systolic (top number) and 100 diastolic (bottom number) at the time of your donation, you may give blood. Furthermore, medications that you may be taking for high blood pressure do not disqualify you from donating.

Myth 8 - I can't give blood because I have high cholesterol.
A high cholesterol level does not disqualify you from donating–even if medication is used to control it. In fact, when you donate blood with us you will get a FREE cholesterol screening!

Myth 7 - I can't give blood because I had cancer.
While some types of cancer may disqualify you from donating, there are many circumstances under which you may donate blood after an appropriate waiting period.

Myth 6 - I can't give blood because I'm diabetic.
Diabetics may donate blood as long as the other medical requirements are met. However, the use of bovine derived insulin will result in deferral from blood donation.

Myth 5 - I can't give blood because I have epilepsy or seizures.
Epilepsy or seizures do not disqualify you from donating.

Myth 4 - I can't donate because I'm anemic.
Your hematocrit (iron) level will be checked prior to donating blood. As long as levels are normal on the day of donation, you may give.

Myth 3 - I can't give blood because I had a flu shot.
In fact, you may donate blood the same day you receive the vaccination as long as you are feeling well.

Myth 2 - I can't give blood because I'm on medication.
In nearly all cases, medications will not disqualify you as a blood donor. As long as you are healthy and the condition is under control, you will very likely be able to donate.

Myth 1 - I can't give blood because I'm afraid of needles.
Most people do feel a bit of nervousness about blood donation. Most also say after their donation that they're sorry they waited so long. Blood donation is a momentary discomfort for the donor that can provide a lifetime of a difference for the patient.

Types of Donations

Why Donate Blood?

You don’t need a special reason to give blood. You just need your own reason.

  • Some of us give blood because we were asked by a friend.
  • Some know that a family member or a friend might need blood some day.
  • Some believe it is the right thing we do.

Whatever your reason, the need is constant and your contribution is important for a healthy and reliable blood supply. And you’ll feel good knowing you've helped change a life.

But people should not donate blood if their lifestyles put them at risk for HIV, hepatitis B, malaria, or other infections that can be transmitted through blood.

These factors also bar you from giving blood:

  • You have had a recent tattoo.
  • You or someone in your family has or had Creutzfeldt-Jakob disease.
  • You had an injection of beef insulin made from cattle in the United Kingdom.
  • You recently had malaria.
  • You have lived in the United Kingdom for more than three months or in Europe for more than six months anytime after 1980.
  • You have been treated for syphilis or gonorrhea in the last year.

Types of Donations

Donation of 'whole blood' is the most common type of blood donation, but there are a few other types of blood donation. Donation types include:

  1. Blood (or Whole Blood)
  2. Double Red Cells
  3. Platelets
  4. Plasma
  5. Autologous Donation
  6. Directed Donation
1. Blood (or Whole Blood)
  • This is the most common type of donation, during which approximately a pint of 'whole blood' is given.
  • The blood is separated into transfusable components – red cells, plasma, platelets and/or cryoprecipitated AHF.
  • This type of blood donation usually takes about an hour, though the actual donation takes about 8-10 minutes.
  • You are eligible to donate 'whole blood' every 56 days.
2. Double Red Cells
  • Double red cell donation is done with the help of an apheresis machine which collects the red cells but returns most of the plasma and platelets to the donor.
  • Red cells are the most transfused blood component, and certain blood types are often in short supply.
  • Double red cell donations from Type O donors and donors with Rh-negative blood types play a very important role in maintaining blood supply levels.
  • Donors need to meet slightly higher hemoglobin and body height/weight requirements in order to be able to give a double red cell donation.
  • Double red cell donations take approximately 30 minutes longer than a whole blood donation and allow you to give two units of red cells.
  • Available in most donation centers and some blood drives.
  • Donors are eligible to give double red cells every 112 days.
3. Platelets
  • Platelet donations are collected at select American Red Cross Blood Donation centers only.
  • During this type of donation, an apheresis machine collects the platelets and some plasma and returns the red cells and most of the plasma back to the donor.
  • Platelets are a vital element of cancer and organ transplant treatments, as well as many surgical procedures as they help prevent massive blood loss.
  • A single donation of platelets collected by apheresis can constitute one or several transfusable units, while it takes about four to six whole blood donations to constitute a single transfusable unit of platelets.
  • The donation takes approximately one and-a-half to two and-a-half hours.
4. Plasma
  • Plasma is collected simultaneously with a platelet donation and is collected at select American Red Cross Donation Centers only.
  • During a plasma apheresis donation, the blood is collected by a machine, which separates the plasma, red cells and platelets and returns the red cells and/or platelets back to the donor.
  • While donors with Type AB blood can only give red cells to other Type AB recipients, they are the universal plasma donors. The ‘right type’ donation for AB donors may be an apheresis donation of plasma or plasma and platelets.
  • The donation takes approximately 1 hour and 15 minutes.
5. Autologous Donation
  • These are donations that individuals give for their own use with a doctor's prescription - for example, before a surgery.
  • Not subject to the same testing criteria as other donations, and therefore, if they are not used by the patient, they are discarded.
6. Directed Donation
  • Donations made for a specific patient by a friend or family member with a doctor's prescription.
  • Subject to all testing requirements of other donations, and if for some reason they are not or cannot be utilized by the patient, they may be made available for other patients in need.

Donation Process

  1. Getting ready for your donation
    • Hydrate
      Be Sure to drink plenty of fluids on the day of your donation.
    • Wear something comfortable
      Wear clothing with sleeves that easily be rolled up above the elbow.
    • Maintain a Healthy Level of iron in your diet before donating
      If possible, include iron-rich foods in your diet, especially in the weeks before your donation.
    • Bring a List of medications you are taking
      We will need t o know about any prescription and/or over the counter medications that may be in your system.
    • Bring an Identity Card
      Please bring either your donor card, driver’s license or two other forms of identification.
    • Bring a friend
      Bring along a friends, so you both may enjoy the benefits of giving blood.
    • Relax!
      Blood donation is a simple and very safe procedure so there is nothing to worry about.
  2. The donation process step-by-step
    • Registration
      - Any staff or volunteers will sign you in and go over basic eligibility and donation information.
      - You will read information about donating blood, and will be asked to show a donor card, driver's license, or other forms of Identification.
    • Health History and Mini-physical
      - You will answer some questions during a private and confidential interview about your health history and places you have traveled.
      - We will check your temperature, pulse, blood pressure and hemoglobin level present in a sample of blood.
    • The Donation
      - We will cleanse an area on your arm and insert a brand new sterile needle for the blood draw. This feels like a quick pinch and is over in seconds.
      - The actual donation takes about 8-10 minutes, during which you will be seated comfortably. Certain donation types, such as platelets, red cells or plasma (apheresis donations) can take up to 2 hours.
      - When approximately a pint of blood has been collected, the donation is complete and a staff person will place a bandage on your arm.
    • Refreshments
      - After donating, you should have a snack and something to drink in the refreshments area. You can leave the site after 10-15 minutes and continue with your normal daily activities.
      - Enjoy the feeling of accomplishment knowing that you have helped save lives.
  3. After the donation
    • Hydrate More You should continue to drink water throughout the day of your donation.
    • Avoid Heavy Lifting or Exercise Try not to exert yourself too much for the rest of the day.
    • Accept Our Most Sincere Thank You!
      Also accept the thanks of people whose lives were changed by blood donations.
    • Connect with Other Donors from your facebook friends!
      - Like our facebook page
      - Download our app into your mobile, fill your profile data and donation detail to share with your facebook friends for motivating them to donate blood next time.
      - Share your story about why you donate.

Enjoy the feeling of knowing that you helped save lives!