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Diseases & Conditions > Blood Donation and Transfusion
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Blood Donation and Transfusion

Medically Reviewed by Celso Bianco, MD

Executive Vice President
America's Blood Centers
Washington, DC

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What Is It?
Donating blood is vital to replenishing our nation's blood supply and saving the lives of critically ill or injured patients in need of blood transfusions.
Every year, nearly five million Americans need blood transfusions. An estimated 43,000 pints (or units) of donated blood are used each day in the United States, and one in seven people entering the hospital needs blood. Women are critical to the country's blood supply, since their role as caregivers sends a message that donating blood is the right thing to do. However, they are also more likely than men to be temporarily restricted from donating because of low hematocrit, or red blood cell levels if they are still menstruating.

Blood Shortages: Why Donating Blood Is Important
Unfortunately, the country's blood supply on occasion runs on perilously thin margins. Blood shortages occur periodically when supply doesn't keep up with demand. But if only one more percent of the United States population would give blood, these shortages would disappear for the foreseeable future.

Shortages occur for numerous reasons, including generational differences and behaviors associated with giving blood and an increased need for blood transfusions. Blood banks work hard to make it as easy and convenient as possible to donate blood. Still, there are numerous restrictions on who can donate blood, with an estimated 62 percent of the American population unable to donate.

How Do You Donate Blood?
Donating blood is relatively simple and entirely safe, however, taking just an hour and requiring little preparation. There is little risk of adverse reaction when donating blood, and you can donate whole blood every 56 days; blood platelets every three days, up to 24 times a year. However, a few people may feel dizzy or faint during the process. In general, this can be prevented by eating a good meal and drinking a lot of fluids (not caffeine) before the donation.

Is the Blood Supply Safe?
The blood supply today is extremely safe, with the risk of catching a blood-borne disease via a transfusion miniscule. Research is underway to make the blood supply even safer via blood sterilization. Transfusions carry other risks, including the risk of receiving the wrong blood type and of contracting a rare lung condition that can be deadly.

The Blood Transfusion Process
During a transfusion, any one of several blood components may be transfused, including blood platelets, which help blood clot; red cells, which carry oxygen; and plasma, the watery fluid that transports cells and nutrients and replaces blood volume.

What Are the Different Blood Types?
There are four types of blood—O, A, B, and AB—and each type can be positive or negative, referred to as the Rh factor. In an emergency, anyone can receive type O negative blood, regardless of his or her own blood type. Researchers have also developed medicines that may help mimic the actions of some blood parts. Throughout your life, you will undergo numerous blood tests. The most common blood test, called a complete blood count, or CBC, measures the number of white and red blood cells, your hemoglobin and hematocrit values and your platelet count. Another slew of blood tests, referred to as a comprehensive metabolic panel, provide important information about your kidneys, liver, blood sugar and blood proteins.

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Facts to Know

  1. Every year, nearly five million Americans need blood transfusions, while an estimated 43,000 pints of donated blood are used each day.

  2. This country has a severe blood shortage.

  3. It takes just an hour from start to finish to donate blood.

  4. As caregivers, it is particularly important that women donate blood because it sends a signal to other family and friends that donating blood is safe, painless and appropriate.

  5. Donating blood is perfectly safe, with no risk of contracting any blood-borne diseases.

  6. You can donate blood every 56 days.

  7. Women who still menstruate may have low iron levels that temporarily prevent them from donating blood, but they can return and donate once their iron levels return to normal.

  8. The U.S. blood supply is very safe, with little chance of diseases like HIV being transmitted via blood transfusion.

  9. About 85 percent of Americans have Rh-positive blood.

  10. In an emergency, anyone can receive type O negative red blood cells. People with this type of blood are known as "universal donors."

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Key Q&A

  1. Why should I donate blood?

    Every year, nearly five million Americans need blood transfusions, and an estimated 43,000 of donated blood are used each day in the United States. Yet the country's blood supply runs on perilously thin margins.

  2. Why isn't there enough blood?

    Several reasons: The World War II generation, which has always been the greatest donor of blood products, is getting older and fewer. Subsequent generations simply haven't taken up the call to donate. Today, just five to 10 percent of Americans donate blood, even though 38 percent are eligible.

  3. Who can donate blood?

    The criteria are comprehensive, covering everything from the type of medication you're taking to any illnesses past or current. Briefly, you must be 17 or older to donate blood and weigh at least 110 pounds. You cannot donate if you have ever tested positive for HIV or Hepatitis B or C or have a clotting disorder or have taken human pituitary-derived growth hormone.

  4. Are there certain medications that disqualify me from donating blood?

    Most medications do not interfere with your ability to donate blood, although some require that you be finished taking the medicine for several days before donating. You cannot donate blood if you have ever taken etretinate (Tegison) or human pituitary-derived growth hormone.

  5. If I have traveled in the United Kingdom, can I still donate blood?

    Not if you've spent three months or more cumulatively in the UK between 1980 and 1996.

  6. Will I have a reaction after donating blood?

    A few people may experience some nausea and dizziness and may notice a bruise, redness or swelling at the needle insertion site.

  7. May I still donate when I'm menstruating?

    Absolutely, as long as you feel OK and don't have low iron levels.

  8. Do I need to make any special preparations prior to donating?

    Yes. You should eat and drink heartily the day of your donation, avoid caffeine and alcohol and refrain from exercising. You should wear comfortable clothing and bring a picture ID to the donation site.

  9. What should I do if I become sick or discover something that may make the transfusion harmful to a patient after I've already donated blood?

    Immediately call the blood center where you donated blood so they can take the necessary precautions.

  10. Do I have to know my blood type before donating?

    No. The blood center will test your blood to determine its type and will let you know your blood type a few days after your donation.

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Lifestyle Tips

  1. Fight your fear of needles

    Donating blood does involve a needle, and probably always will involve a needle. To combat your fear, keep in mind that the patient at the other end of the donation probably also doesn't like needles, but is now sick, vulnerable and dependent on transfusion being available. She doesn't have an option when it comes to needles. To make your first donation easier, bring a friend who has donated blood. If you're nervous, tell the staff. Blood center personnel deal with people all the time who are uncomfortable, and they know how to make you comfortable, as well as celebrate your success with you when you're finished.

  2. Plan ahead for a smooth donation

    First, read through the information on donor eligibility included here and on blood donation Web sites to make sure you're eligible to donate. If you have any medical conditions or are taking any medication, talk to your health care professional to ensure you can donate blood. Then make an appointment with the blood center closest to you. Turn up on time and bring a picture ID. Make sure you eat normally the day of your donation and drink plenty of non-caffeinated, nonalcoholic fluids. Wear comfortable clothing with short sleeves or sleeves you can roll up. Don't exercise the day you're planning to donate, and don't plan to exercise vigorously for several hours after your donation.

  3. Avoid dizziness or lightheadedness after donating

    Ask the nurse in the post-donation area for a large glass of water. Studies find that drinking about 16 ounces of water right before or after donating can prevent fainting.

  4. Mark your donation date on the calendar

    Mark your calendar for 56 days from the date of your donation. That's when you're eligible to donate again.

  5. Ensure you get the right blood type

    If you need a blood transfusion, make sure you know your blood type before going to the hospital or clinic, and then double-check that the blood you're receiving is the correct blood. Conversely, if your doctor says you need a transfusion, ask why. Standards for transfusion are in flux, and you may be able to get by just fine without a transfusion.

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Need for Donors

Why Donate? Blood Shortages
Unfortunately, we experience frequent blood shortages in this country. According to America's Blood Centers, more than 43,000 pints of donated blood are used each day, and nearly five million Americans need blood transfusions annually. One in seven people entering the hospital need blood, and someone in this country needs blood every two seconds.

It wouldn't take much to improve the situation. If all current blood donors gave blood just three times a year (the average is two times a year), blood shortages would be a rare event, experts say.

Major Reasons for Blood Shortages
A major reason for the blood shortage is that even though 38 percent of the country's population is eligible to donate blood, only about five to 10 percent does. There are three main reasons for the shrinking numbers, say experts:

  1. Changing demographics
    Since blood transfusions became commonplace in the 1950s, blood centers have depended on the World War II generation for donations. This generation is now aging and has fewer eligible donors, and Baby Boomers and the generations that follow simply don't donate as much. Experts aren't sure why, but suspect it may be related to differences in lifestyle, the level of altruism and the fact that the blood community may not be effectively appealing to these generations.

  2. Increasing need for blood
    As surgeries become more complex and cancer treatments more aggressive, and as people live longer, according to the American Red Cross, this country uses about six percent more blood every year.

  3. Increasing blood donor rejection rate
    Beginning with the AIDS epidemic in the early 1980s, the blood supply has gotten much safer. But that's required turning away more and more potential donors. Today, increasingly sophisticated and sensitive tests, coupled with significantly more questions on application forms designed to weed out donors who may transmit blood-borne diseases, means there are fewer people who are able to donate blood even if they want to. For instance, people who have spent three or more months in the United Kingdom between 1980 and 1996 cannot donate blood for fear they could introduce the human version of mad-cow disease, variant Creutzfeldt-Jakob Disease (vCJD), into the blood supply.

  4. Blood products are perishable
    Red blood cells have a shelf life of 42 days, platelets just five days, so blood donations are needed every day, 365 days a year.

Why People Don't Give Blood
The greatest barrier that prevents people from donating is a lack of convenience and a lack of knowledge of the importance of donating, experts say. And it is important. Every pint of donated blood saves three lives, and someone needs blood every two seconds.

Then there are people's perceptions about blood donation and the excuses they give for not donating. According to the American Red Cross, the most common excuses people give for not giving blood include the following:

  • I'm afraid of needles. However, most donors say they only feel a pinch.
  • I'm too busy. But most donations take less than an hour from start to finish.
  • I didn't know there was a need for blood. Every two seconds, someone needs blood, and 43,000 units are needed each day.
  • I already gave this year. You can give blood every 56 days, and many donors give five times a year.
  • I'm afraid of AIDS. These days, it is not possible to get AIDS by donating blood because a new sterile needle is used each time.
  • I don't have the right blood type. Every blood type is needed.
  • I can't spare the blood. The average adult has 10 to 12 pints of blood, and donated blood is quickly replaced, usually within 24 hours.

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Types & Tests

Types of Blood
Blood cells—red, which carry oxygen; white, which fight infection; and platelets, which help with clotting—are produced in your bone marrow. They are carried throughout your body in plasma, a pale yellow mixture of water, proteins (produced primarily in your liver) and salts.

There are four main types of blood, and each type can be either Rh positive or negative:

Blood TypePercentage of Population

Your Blood Type & What Blood You Can Receive
In an emergency, anyone can receive type O red blood cells. People with type O are known as "universal donors." Type AB individuals can receive red blood cells of any ABO type. They are known as "universal recipients." They can also give plasma to all blood types.

The Rh Factor
The positive or negative nature of your blood type is called your Rh factor. You may have heard about Rh factor in connection with pregnancy. About 85 percent of Americans have Rh-positive blood. If you have Rh-negative blood and get pregnant by a man with Rh-positive blood, some or all of your children will have Rh-positive blood, but some may be Rh-negative like you.

Rh & Pregnancy
In every pregnancy, some blood cells from the fetus may pass through the placenta and enter your bloodstream. If you are Rh-negative and your baby is Rh-positive, you may react to these "foreign" invaders as if you were allergic to them, building up antibodies capable of destroying the baby's red blood cells.

This is typically fine if this is your first pregnancy. But complications may occur with future pregnancies. By then, enough antibodies may have built up in your system so when they pass through the placenta to enter the fetus's blood they begin to destroy the baby's blood cells, producing anemia and on rare occasions resulting in the death of the baby.

To prevent this, women who are Rh-negative who have had an Rh-positive baby should receive an injection of "Rh-immunoglobulin" within 72 hours after giving birth, having an abortion or miscarrying. This prevents Rh sensitization. In addition, they need to have the injection in the 28th week of their pregnancies to prevent the few red blood cells that cross the placenta into the mother's circulation during pregnancy from starting the immunization process

Artificial Blood
There is currently no alternative to human blood, but researchers are looking into ways to make blood artificially. Researchers have also developed medicines that may help mimic the actions of some blood parts. For example, a medicine called erythropoietin can help people with kidney problems make more red blood cells so they require fewer blood transfusions. In addition, surgeons are trying to reduce the amount of blood lost during surgery and to collect and reuse the patient's blood so fewer blood transfusions are required.

Blood Tests and What They Mean
Blood comprises seven to nine percent of your total body weight. Yet just a few drops are all that's needed for the most common blood test—a complete blood count, or CBC. It includes five major measures that provide valuable clues to your overall health.

The reference ranges given below are slightly different for every laboratory. They should be regarded as approximations, and the results for a particular person's tests should be compared to the reference range for that lab.

  • White blood cell (WBC) count. This measures the number and type of white blood cells, which fight infection. The "differential" is the measurement of the five main types of white blood cells: neutrophils (polys, or mature neutrophils, and bands, or young polys) basophils, eosinophils, lymphocytes and monocytes. A normal overall WBC range is 4,500 to 10,000 cells/mcL, but you also want to know the results of the differential, or the specific number of neutrophils, lymphocytes, monocytes, eosinophils and basophils. According to the American Association for Clinical Chemistry, a standard reference range is not available for this test because values are dependent on many factors.
  • Red blood cell (RBC) count. Normal range is 4.7 to 6.1 cells/mcL for males and 4.2 to 5.4 million cells/mcL for females. The mean cell volume (MCV) measures the approximate size of the red blood cell. A normal range is 80 to 95.
  • Hemoglobin (HGB) value. Normal range varies but in general is 13.8 to 17.2 g/dL for males and 12.1 to 15.1 g/dL for females. Low hematocrit an d hemoglobin levels mean you could have anemia.
  • Hematocrit (HCT) value. Normal range is 40.7 to 50.3 percent for males and 36.1 to 44.3 for females.
  • Platelet count. Normal range is 150,000 to 450,000 platelets per microliter. Without enough platelets, you could have a condition called "thrombocytopenia," which causes you to bruise easily

The Metabolic Panel
Your health care professional may also order a comprehensive metabolic panel (CMP). These 14 tests, routinely ordered as part of a blood work-up for a medical exam or yearly physical, provide important information about the current status of your kidneys, liver and electrolyte and acid/base balance as well as your blood sugar and blood proteins. For best results, you should fast 10 to 12 hours before the test.
Not all tests described below have ranges listed for them because the American Association for Clinical Chemistry notes that reference ranges for many tests are specific to the laboratory that produces the results. Your test results should show you a "normal" range next to your result. Here are some of the tests included in a metabolic panel:

  • Glucose levels: Screens for and monitors diabetes, prediabetes and low blood sugar. Normal range is from 70 to 99 mg/dL. Levels from 100 to 125 mg/dL suggest pre-diabetes, and 126 mg/dL and above probable diabetes.
  • Calcium: Measures calcium levels in your blood.
  • Albumin: Screens for a liver disorder or kidney disease and evaluates nutritional status.
  • Total protein: Screens for certain liver and kidneys disorders, as well as other diseases, and helps determine your nutritional status.
  • Electrolytes: Screens for sodium, potassium, carbon dioxide/bicarbonate and chloride levels. Among other things, provides an overview of your body's fluid and electrolyte balance.
  • BUN (blood urea nitrogen) and creatinine: Evaluates your kidney function.
  • Liver function tests: Includes ALP (alkaline phosphatase), ALT (alanine aminotransferase), aspartate aminotransferase (AST) and bilirubin, among others.

Other Common Blood Tests for Women

  • Thyroid test: The American Thyroid Association recommends adults age 35 and older should be screened every five years for thyroid problems using the TSH test.
  • Cholesterol test: The American Heart Association recommends everyone 20 and older have their blood cholesterol measured at least once every five years. Ideally, your total cholesterol should be below 200 mg/dL, your LDL (or "bad" cholesterol) less than 100 mg/dL and your HDL ("good" cholesterol) 60 mg/dL or more (the higher your HDL level the better).

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Blood Supply Safety

Is Our Blood Supply Safe?
Americans who believe the U.S. blood supply is unsafe are worrying for no reason. According to the Food and Drug Administration, the American blood supply is safer than it ever has been.

Government Safety Standards
The FDA is responsible for ensuring the safety of the nation's blood supply. Overall, up to 14 tests are performed on every unit of donated blood, including testing for seven infectious agents: syphilis, hepatitis B and C, HTLV I and II (the virus that causes a form of leukemia), and HIV I and II. Today, blood centers use a testing protocol called NAT, or nucleic acid testing, to simultaneously test for HIV and Hepatitis C. NAT is capable of detecting more infectious agents than tests previously used because it detects viral genes rather than antibodies or antigens (proteins from the virus). This enables earlier detection, even before the donor knows he/she is infected, because the appearance of antibodies requires time for the donor to develop an immune response, and detection of antigens requires time for a higher level of virus to appear in the bloodstream.

In recent years, the FDA has significantly increased its oversight of the blood industry. Today, the FDA inspects all blood facilities at least every two years, visiting "problem" facilities more often. Blood establishments are now held to quality standards comparable to those expected of pharmaceutical manufacturers.

Blood Donor Screenings
Blood donors are also asked specific and very direct questions about risk factors that could indicate possible infection with a transmissible disease. This "up-front" screening eliminates approximately 90 percent of unsuitable donors. The FDA also requires blood centers to maintain lists of unsuitable donors to prevent the use of collections from them.

The tight regulation of the blood supply means that blood centers can move quickly when new infectious disease agents are identified. For instance, when West Nile virus emerged in the United States in 1999, blood officials immediately began researching whether it could be transmitted via the blood supply. By late 2002, it was clear that the virus could be transmitted via blood products, and in July 2003, officials implemented a post-donation test for the virus.

Blood Sterilization
Although the FDA notes on its Web site that a totally "risk-free" blood supply may never be attainable, researchers around the world still search for ways to reach that goal. One promising technique uses a procedure called "pathogen inactivation," or sterilization. The procedure involves adding a chemical to a bag of blood to "break up" the genetic material of any viruses or bacteria so they can't infect a recipient.

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Donating Blood

Who Can Donate
To be eligible to donate blood, you must be in good health and at least 17 years old (although some states permit younger people, with parental consent, to donate). Few have any upper age limit. Generally, donors must weigh at least 110 pounds, and all must pass a physical and health history examination given before donation. "Healthy" means you feel well and can perform normal activities. If you have a chronic condition such as diabetes or high blood pressure, "healthy" also means your condition is controlled with treatment.

Although the U.S. Food and Drug Administration (FDA) sets most blood donation guidelines, some additional criteria are set by the blood donation centers. So the information below should be taken as a guide only. Check with your blood center about its specific rules.

Donor eligibility rules are intended to protect the health and safety of the donor, as well as the patient who will receive the transfusion. If you have any kind of medical condition, you should check with your health care professional about your ability to donate blood.

Donation Safety
There is absolutely no way you can contract any virus or illness by donating blood. All materials used to collect blood are new. They have been sterilized by the manufacturer and never been used before and are thrown out immediately after use.

How to Donate
First, check the list of exceptions for donation to see if you are eligible to donate. If you have any questions, call your health care professional or your local blood donation center. To find the closest blood center near you, call the American Red Cross or the America's Blood Centers hotlines or visit their Web sites to set an appointment. The American Red Cross and other blood banks are doing all they can to make blood donation as easy as possible by bringing opportunities to donate to the donors, through work-site and community blood drives.

On the day of your appointment, follow these recommendations:

  • Eat heartily and drink fluids (non-caffeinated, nonalcoholic) before you donate.
  • Don't exercise immediately before you donate blood.
  • Arrive on time. Most of the people staffing blood centers are volunteers. It's not fair to waste their time, and they try hard not to waste yours.
  • Bring a picture ID. You'll be asked to prove your identity and to provide proof of your name, date of birth and Social Security number.
  • Relax during the donation, which only takes about 10 to 15 minutes.

What to Expect at Your Donation Appointment
When you arrive at the donation center, you'll register and answer a series of questions concerning your medical history. Then a medical staffer will conduct a health examination and measure your pulse, blood pressure, temperature and red cell level. You may feel a little pain when the needle goes in. Some people don't feel any pain. It might help to look away while the needle is inserted. You'll sit or lie down for about 10 to15 minutes while a pint, or unit, of blood is collected.

Donating blood is strictly a volunteer activity—there is no payment. There are plasma centers in some cities, however, where you can receive compensation for donating plasma, the fluid that transports blood cells.

Apheresis Donation
In addition to the regular method of donating blood, in which the blood is permanently removed from your body, you may donate blood platelets through a process called apheresis. During this type of donation, blood passes through a special machine called a "blood cell separator" that uses centrifugal force (basically, spinning the blood around very fast) to separate the various blood components. The portion of the blood desired, such as the platelets, are then collected, while the rest of the blood products—plasma, hemoglobin and white blood cells—are returned to the donor.
Apheresis takes longer than traditional blood donation—about two hours—but it contains six to eight times more platelets than one whole blood donation. And because blood platelets are replenished quicker than red blood cells, you can donate every three days, although no more than 24 times a year.

Double Red Blood Cell Donations
To increase the amount of blood product collected during each donation (and thus reduce the number of donors needed), many blood centers now offer "double red blood cell donations." These are a different type of blood donation where, instead of collecting blood into individual collection bags as it comes from the donors' veins, the blood is collected into a machine. The machine keeps just the red blood cell portion of the blood and returns the other blood elements to the donor. In this way, two full doses of red cells, the most important part of the donation, can be collected at one time. Looked at another way: donors only have to donate blood once to give the equivalent of two blood donations. Unfortunately, many women do not qualify to donate double red cells because they have a lower overall blood volume than men.

What Happens After Your Donation Appointment?
After donating, you should receive a form with a number to call in case you learn after your donation that your blood may not be safe to give to another person. It is very important that you call that number if you discover that you have an infectious disease that can be spread through blood products.

How Will You Feel After Giving Blood?
Although most people feel fine after donating, a few have some nausea, a faint or dizzy feeling, or a black and blue mark, redness or pain where the needle entered. This is perfectly normal.
After donating, you're asked to relax for a few minutes while you're served a light snack. While you're resting, ask the nurse for a large glass (about 16 ounces) of water. Studies show that drinking water before and after donating can prevent fainting.

After donating, you should avoid muscle exercises, rough movements and heavy activities such as weight lifting or picking up heavy objects for the first four to five hours. Then mark your calendar: You can donate again in 56 days. If you donate every 56 days, you'll be able to donate six times a year. Over your lifetime, you could conceivably donate 48 gallons of blood if you live to age 76!

When Can You Give Blood Again?
Overall, you must wait at least eight weeks between whole blood (standard) donations, at least three days between platelet apheresis donations and at least 16 weeks between double red cell (automated) donations.

When Can You Not Give Blood?
There are certain situations in which a person is unable to give blood, and is turned away at the blood donation center. Deferrals can be temporary or permanent, and are detailed below.

Temporary Deferral
If you have experienced any of the following health situations in the bulleted list immediately below, you may find yourself "temporarily deferred." It means you can't give blood that day, but you can come back once you no longer meet the specific criteria.

If you are temporarily deferred, or turned away, at a blood donation center, ask the staff at the blood center what you need to do to be able to donate. In some instances, you may just need to wait a few weeks. In others, you may need some medical attention. Don't take the deferral as a personal affront or insult. It definitely is not personal. And the blood centers really need your donation. So mark your calendar for the date when you can return to try again.

You may be temporarily deferred if you:

  • Have had a heart attack in the last six months.
  • Have had malaria in the last three years, lived in an area where malaria is found in the last three years or traveled to an area where malaria is found in the last 12 months.
  • Have received blood, plasma or other types of blood components in the last year. You must wait 12 months after receiving a blood transfusion from another person in the United States before donating blood. And you may not donate if you received a transfusion since 1980 in the United Kingdom (England, Wales, Scotland, Northern Ireland, Channel Islands, Isle of Man, Gibraltar or Falkland Islands). This requirement is related to concerns about variant Creutzfeldt-Jakob disease (vCJD), or "mad cow" disease.
  • Have received a blood transfusion in certain African countries since 1977.
  • Have been tattooed in the last year (you must wait 12 months after a tattoo).
  • Have had cardiac surgery, a heart attack or an episode of angina in the last six months. Discuss your particular situation with your health care provider at the time of donation.
  • Have been exposed to someone with hepatitis within the last year.
  • Are not feeling well the day of the blood donation.
  • Have an acute infection. If you are taking an antibiotic, the reason for the antibiotic must be evaluated to determine if you can transmit the infection via blood. You can donate after you have finished a course of oral antibiotics for a bacterial or viral infection as long as you have taken the last pill as of the date of donation. If you received an antibiotic by injection, you can donate as long as it has been 10 days since your last injection. If you are taking antibiotics to prevent an infection, the responsible medical director will evaluate whether or not you can donate.
  • Have a temperature above 99.5 degrees Fahrenheit.
  • Are pregnant or have had an abortion in the last six weeks. Wait six weeks after giving birth before donating blood.
  • Have had oral surgery or treatment for an abscess or infection of the mouth. In this instance, you should wait three days before attempting to donate blood.
  • Have had immunizations for German measles (rubella), MMR (measles, mumps and rubella), or chicken pox. In those instances, wait four weeks before donating. If you've been immunized against red measles (rubeola), mumps, polio or yellow fever, wait two weeks. Wait seven days after immunization for Hepatitis B (unless you were given the immunization for exposure to hepatitis B. Then wait 12 months). There are also various waiting periods after receiving smallpox vaccine, depending on your reaction to the vaccine.
  • Have been treated for syphilis or gonorrhea. Wait 12 months before donating.

Certain drugs also carry certain waiting periods. The Red Cross lists the following waiting times after you have taken your last dose:

  • isotretinoin (Accutane), finasteride (Proscar and Propecia): Wait four weeks.
  • dutasteride (Avodart): Wait six months.
  • aspirin: No waiting period for donating blood. However, you must wait 48 hours after taking aspirin or any medication containing aspirin before donating platelets by apheresis.
  • warfarin (Coumadin), heparin or other prescription blood thinner: Wait seven days after discontinuing.
  • human pituitary-derived growth hormone: You are not eligible to donate blood.
  • hepatitis B immune globulin (given for exposure to hepatitis): Wait 12 months after exposure to hepatitis.
  • clopidogrel (Plavix): Wait seven days before donating platelets by apheresis.
  • acitretin (Soriatane): Wait three years before donating.
  • etretinate (Tegison): You are not eligible to donate blood.
  • ticlopidine Hcl (Ticlid): Wait seven days before donating.

Low Hemoglobin Count in Women
One reason women donate blood less often than men may have to do with the fact that women who are still menstruating are more likely to have lower hematocrit, or red blood cell, levels than men. Having adequate iron stores is important for donation since iron is needed to make hemoglobin, the red pigment that carries oxygen inside red cells. Without adequate iron, you will not be able to make up for blood lost through menstruation or through donation. The U.S. Food and Drug Administration (FDA) requires that all donors have a blood hemoglobin level of at least 12.5 g/dL.

That doesn't mean women can't eventually donate. They just need to get their iron levels up either through diet or supplements. Don't try to do this on your own, however. If you learn that your iron levels are low when you try to donate blood, see a health care professional. You may need prescription iron supplements to return your levels to normal.

But women are critical when it comes to this country's blood donors. According to the American Red Cross, women make up 50 percent of blood donors. As family caregivers, women hold a great deal of influence when it comes to blood donation. When a woman donates blood, experts say, she sends the message to others that it is safe, painless and appropriate. She also sends a message that donating blood is a nurturing, selfless and kind act that is very much within the traditional role of women. Women also receive the majority of blood transfusions—about 53 percent.

Permanent Deferrals
If you meet any of the following criteria you will be permanently deferred, which means you cannot donate blood. If you are permanently deferred, you cannot donate blood. But you can still help. Ask your blood center about volunteer opportunities or offer to organize a community or workplace blood drive.

  • You have ever tested positive for hepatitis B or hepatitis C.
  • You have had hepatitis (inflammation of the liver) caused by a virus or unexplained jaundice (yellow discoloration of the skin) since age 11.
  • You have had leukemia or lymphoma, including Hodgkin's Disease, or any other cancers of the blood. If you have had another type of cancer, you can donate if the cancer has been treated successfully and it has been more than 12 months since treatment was complete and you've experienced no cancer recurrence in that time. If you have had a lower risk cancer, such as a squamous or basal cell skin cancer that has been completely removed, you do not have to wait 12 months. In addition, if you have had a precancerous condition of the cervix, you can still donate as long as the abnormality has been successfully treated.
  • You are at high risk of contracting the HIV virus/AIDS or are already infected with the virus.
  • You have sickle cell disease. If you have sickle cell trait, however, you can donate.
  • You have spent any cumulative period of three or more months in the United Kingdom from 1980 through 1996.
  • You had a blood transfusion in any of the following countries in the United Kingdom between January 1, 1980, and the present: Channel Islands, England, Falkland Islands, Gibraltar, Isle of Man, Northern Ireland, Scotland and Wales.
  • You have a clotting disorder, such as von Willebrand's disease or hemophilia. (If you have a clotting disorder from Factor V and are not on anticoagulants, you are eligible to donate, however). You should also not donate if you are currently taking any "blood thinner" medication such as warfarin or heparin.
  • You have ever received a dura mater (brain covering) transplant or human pituitary growth hormone. This requirement is related to concerns about variant Creutzfeldt-Jacob disease. You are also not eligible to donate if you have a close family member who has had the disease, or if you are in a family that has been told they have a genetic risk for the disease.

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Blood Transfusions

When you give blood, you're actually giving several products that can be transfused into several different people for various reasons. Blood is composed of plasma, platelets and red cells. All blood donations are processed and available for use approximately 24 to 48 hours after donation. After processing, red cells can be stored for 42 days, plasma can be frozen and stored for up to 12 months and platelets (from whole blood or by apheresis) expire after 5 days and are stored at room temperature.

Blood Components & How They Are Used

  • Plasma is the watery fluid that transports cells and replaces blood volume. It is required to maintain blood pressure and assist in clotting. It also contains proteins that may help fight disease.
  • Platelets are proteins that help blood clot. They are transfused into patients undergoing transplants and those with leukemia and other cancers.
  • Red cells carry oxygen. They are transfused into patients with anemia, and those who have lost blood during surgery or trauma.
Blood Component UseUnits*
Automobile Accident50 units of blood
Bone Marrow Transplant
20 units of blood
120 units of platelets
Heart SurgerySix units of blood
Six units of platelets
Organ Transplant40 units of blood
30 units of platelets
20 bags of cryoprecipitate
25 units of fresh frozen plasma

*Average usage.

Autologous Transfusions
Autologous blood donation, in which you donate your own blood for use during a surgical procedure, was quite popular in the early 1980s when the risk of HIV infection was very real. But today it's not worth doing if your community has an adequate blood supply. Although autologous donations can spare you some of the very low infectious risks of using the available blood supply, from a cost/benefit standpoint it's a very expensive option to prevent a very few bad outcomes.

Half of all autologous donor blood doesn't even get used and must be discarded. Plus, even if you donate your own blood, you may still have a reaction during the transfusion. Or, your donation could get mixed up with someone else's and used for the wrong patient.

Overall, experts agree, the safest alternative for medically needed transfusion remains your own blood, but, in most cases, this option adds very little from a safety perspective. Still, if you want an autologous blood transfusion for your own peace of mind, all blood centers offer the option.

Are Transfusions Necessary?
One of the simplest ways to stretch the tight blood supply might be changing physician practices about when patients should get transfusions. A growing body of scientific literature suggests that some transfusions might not be necessary. Traditionally, most doctors have transfused patients when their hemoglobin levels drop to 10 g/dL. Today, many doctors think the decision of whether or not to transfuse should be made in the context of other factors as well, including the patient's symptoms and overall health.

Reducing the number of blood transfusions this way could increase the nation's blood supply, making blood more readily available to those in need. To move hospitals in this direction, some blood centers have full-time "transfusion safety officers" who work with hospitals on these and other transfusion-related items. But patients can also play a role, say experts, by asking their doctors: "Is this transfusion necessary?"

Risks of Blood Transfusions
Transfusion errors pose a small but significant risk to patients, occurring at the rate of two errors a day nationwide, on average. And no one really knows how many result in death, since, until fairly recently, hospitals weren't required to report transfusion-related errors that did not result in death. Between October 1, 2005, and September 30, 2006, the FDA received 81 reports of fatalities in patients receiving blood transfusions. Of those, eight were unrelated to the transfusion, 63 resulted from the transfusion, and the other 10 causes of death were undetermined. Yet even if it doesn't result in death, any kind of reaction to the wrong blood can slow your recovery and increase your risk of complications.

The primary reason for most blood-related errors is human mistakes. For instance, the sample from the patient may be mislabeled with another patient's name before it is sent to the lab, and then the wrong unit is sent to the patient for transfusion. Or, in the heat of crisis in the emergency room, someone forgets to double-check a patient's identity and match it with the label on the unit.

To avoid these errors, some hospitals have begun implementing bar code systems for blood transfusions, in which nurses use a scanning wand like those used in grocery stores to make sure the code on the blood matches the code on the patient's bracelet.

In addition to your risk of getting the wrong blood, other risks include bacterial contamination of blood products and a condition called "transfusion-related acute lung injury," a serious pulmonary syndrome that can lead to death if not recognized and treated appropriately. The syndrome is believed to be the third most common cause of blood transfusion-related death. There is also some concern that transfusion may affect the immune system and cause some mild immune suppression.

For these and a multitude of other reasons—not the least of which is the chronically short blood supply—researchers have been scrambling to discover "artificial" blood products and means of maintaining blood products longer. Various types of hemoglobin carriers are being studied, but approval is unlikely in the foreseeable future because of safety concerns.

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Organizations and Support

For information and support on Blood Donation and Transfusion, please see the recommended organizations and Spanish-language resources listed below.

National Hemophilia Foundation
Website: http://www.hemophilia.org
Address: 116 West 32nd Street, 11th Floor
New York, NY 10001
Hotline: 1-800-42-HANDI (1-800-424-2634)
Phone: 212-328-3700
Email: handi@hemophilia.org

National Marrow Donor Program
Website: http://www.marrow-donor.org
Address: 3001 Broadway Street N.E., Suite 100
Minneapolis, MN 55413-1753
Hotline: 1-800-MARROW (627-7692)
Email: patientinfo@nmpd.org

New Jersey Cord Blood Bank
Website: http://www.coriell.org/index.php/content/view/53/104/
Address: Coriell Institute for Medical Research
403 Haddon Avenue
Camden, NJ 08103
Phone: 856-966-7377
Email: donnaa@cbsblood.org

National Heart Lung and Blood Institute
Diseases and Conditions Index
Website: http://www.nhlbi.nih.gov/health/dcisp/index.html
Address: NHLBI Health Information Center Attention Website
P.O. Box 30105
Bethesda, MD 20824
Phone: 301-592-8573
Email: nhlbiinfo@nhlbi.nih.gov

The Journal of American Medical Association
Website: http://jama.ama-assn.org/cgi/content/full/292/13/1646/DC1
Address: Customer Service: North, Central, and South America
Subscriber Services Center
American Medical Association
P.O. Box 10946
Chicago, IL 60654
Hotline: 1-800-262-2350
Phone: 312-670-7827
Email: ama.subs@ama-assn.org