FAQs About Blood and Blood Donation

For a whole blood donation, approximately 0.5 L of blood is collected. For donations of other blood products, such as platelet or plasma, the amount collected depends on your height, weight and platelet count.

Yes, since this helps to ensure the safest possible blood supply. All donors must be asked the screening questions at each donation. Both AABB and FDA regulations specifically require that all blood donors complete the donor history questionnaire on the day of donation and prior to donating.

If you are a frequent blood donor, you may qualify to use an abbreviated Donor History Questionnaire. Ask if this option is available at your blood donor center and whether you qualify to use it.

All donors who have taken a medication to prevent HIV must wait 3 months after the last dose to donate blood.

These medications are called pre-exposure and post-exposure prophylaxis, or “PrEP” for short.

PrEP works to prevent sexual transmission of HIV, but evidence shows that PrEP can interfere with blood donor screening tests for HIV, as well as diagnostic HIV tests, by creating a false-negative test result. With a false-negative test result, the person can unknowingly transmit a virus to a patient who receives the blood.

There are situations where a PrEP-breakthrough infection could happen. When not consistently using PrEP as instructed, an individual who has donated and been exposed to HIV can have undetectable levels of HIV when tested as a blood donor. This is called a false-negative test result, which means that the donor tests negative, but HIV could be present in the donated blood and remain undetectable. With a false-negative test result, the person using PrEP can unknowingly transmit a virus to a patient who receives the blood.

The message “Undetectable = Untransmissible” does not apply to blood donation but PrEP is highly effective in preventing sexual transmission of HIV. The use of blood donor screening questions helps to assess the time frame for a potential false-negative test result to reduce the risk of transmission of undetected HIV to a patient.

Donor deferral means that an individual is not eligible to donate based on the criteria used to protect the health and safety of both the donor and transfusion recipient. A prospective donor may be deferred at any point during the collection and testing process. The period of time a person will not be eligible to donate depends on the specific reason for deferral. After the deferral period ends, a donor can return to the blood donor center to be reevaluated and resume donation if all donor eligibility criteria are met.

Blood donor centers follow donor eligibility criteria based on requirements of the FDA, AABB Standards, and their own local policies. The medical director of the blood donor center has ultimate authority to establish a more stringent deferral policy based on their clinical judgement as a physician.

Refer to the AABB Blood Donor History Questionnaire for the list of questions asked during the donor screening process. Your blood donor center can best answer your questions about donor deferral. Some of the more common reasons for deferral are listed here:

• Anyone who has taken a medication to prevent an HIV infection in the last 3 months
• Anyone who has ever taken any medication to treat an HIV infection
• Anyone who has used needles to take drugs, steroids, or any substance not prescribed by a doctor in the past 3 months
• Men who have had sexual contact with other men in the past 3 months
• Anyone with a positive test for HIV
• Anyone who has engaged in sex for money or drugs in the past 3 months
• Anyone who has had babesiosis or Chagas disease
• Anyone who has taken Tegison for psoriasis
• Anyone who has risk factors for vCJD, including:
  • Anyone who spent three months or more in the United Kingdom countries of England, Northern Ireland, Scotland, Wales, the Isle of Man, the Channel Islands, Gibraltar, or the Falkland Islands from 1980 through 1996
  • Anyone who has spent time that adds up to five years or more in France or Ireland from 1980 through 2001. Time spent in Ireland does not include time spent in Northern Ireland, which is part of the United Kingdom
  • Anyone who received a blood transfusion in France, Ireland, England, Northern Ireland, Scotland, Wales, the Isle of Man, the Channel Islands, Gibraltar or the Falkland Islands from 1980 to the present

  NOTE: FDA no longer recommends donor deferral for time spent on United States military bases in Europe from 1980-1990, including military bases located in the United Kingdom. These donors may be assessed for reentry and may be eligible for donation.

Your blood donor center will inform you if you are permanently deferred or temporarily deferred. The deferral time depends upon the reason for deferral. Prior to each donation, you will be given a mini-physical and medical interview. At that time, it will be determined if you are eligible to donate blood on that day.

Yes. There is no waiting period to donate after receiving a flu shot.

No, blood centers require that you be in good health (symptom-free) and feeling well.

Yes, if your blood pressure falls within the limits set by FDA regulations.

Your blood donor center can best answer your questions. We recommend that you call the blood donor center ahead of time to inquire about any medications you are taking. Aspirin and ibuprofen will not affect a whole blood donation. However, apheresis platelet products can be affected if aspirin or aspirin products are taken 48 hours prior to donation. Many other medications are acceptable.

The entire donation process, from registration to post-donation refreshments, takes about one hour. The actual donation takes about 5-10 minutes.

There are many places where blood donations can be made. Bloodmobiles (mobile blood drives on specially constructed buses) travel to many locations, making it easy for people to donate blood. Many people donate at blood drives at their places of work or at high schools, colleges, churches and other community organizations. People also can donate at community blood centers and hospital-based donor centers. You may use the online Locator to locate a nearby blood center or hospital to donate.

Apheresis, an increasingly common procedure, is the process of removing a specific component of the blood, such as platelets, red blood cells, plasma (liquid part of the blood) or granulocytes (white blood cells) and returning the remaining components to the donor. This process allows more of one particular part of the blood to be collected than could be separated from a unit of whole blood.

The apheresis donation procedure takes longer than that of a whole blood donation. A whole blood donation takes about 20 minutes to collect the blood as compared to an apheresis donation which may take about one to two hours, depending on the blood component(s) that is being donated.

While a given individual may be unable to donate, he or she may be able to recruit a suitable donor. Blood banks are always in need of volunteers to assist at blood draws or to organize mobile blood drives. In addition, monetary donations are always welcome to help ensure that blood banks can continue to provide safe and adequate blood to those in need.

After blood is drawn, it is tested for ABO group (blood type) and Rh type (positive or negative), as well as for any unexpected red blood cell antibodies that may cause problems for the transfusion recipient. Blood is tested for:

• Hepatitis B virus
• Hepatitis C virus
• HIV-1 and HIV-2
• HTLV-I and HTLV-II
• Syphilis
• West Nile virus
• Trypanosoma cruzi, the infectious agent causing Chagas' disease
• Babesia – in states where testing is required by FDA guidance

No. Each unit of whole blood is separated into several components. Red blood cells may be stored under refrigeration for a maximum of 42 days, or frozen for up to 10 years. Platelets are stored at room temperature and may be kept for a maximum of five to seven days. Fresh frozen plasma is kept in a stored frozen state for up to one year. Cryoprecipitated AHF is stored frozen for up to one year. Granulocytes must be transfused within 24 hours of donation.

Other products manufactured from blood include albumin, immune globulin, specific immune globulins, and clotting factor concentrates. Commercial manufacturers commonly produce these blood products.

Most blood centers strive to maintain an optimum inventory level of a three-day supply. Due to unpredictable demands, the inventory often fluctuates hourly. When the blood supply drops below a three-day level, blood centers begin alerting local donors to increase the inventory to a safe operating level.

Scientists have yet to find a successful substitute for human blood. This is why blood donors are so vital to the lives of those who are in need of blood.

The need for blood is great. Every day in the U.S., approximately 29,000 units of red blood cells are required in hospitals and emergency treatment facilities for patients with cancer and other diseases, for organ transplant recipients, and to help save the lives of accident/trauma victims. In addition, nearly 5,000 platelet units and 6,500 units of plasma are also needed. In 2017, nearly 16 million blood components were transfused. With an aging population and advances in medical treatments and procedures requiring blood transfusions, there is always a need for blood and blood components.

The approximate distribution (%) of blood types in the U.S. blood donor population is as follows.*

*Garratty G, Glynn SA, McEntire R; Retrovirus Epidemiology Donor Study. ABO and Rh(D) phenotype frequencies of different racial/ethnic groups in the United States. Transfusion. 2004 May;44(5):703-6. doi: 10.1111/j.1537-2995.2004.03338.x. PMID: 15104651.

In an emergency, anyone can receive type O red blood cells. Therefore, people with type O blood are known as "universal donors." In addition, individuals of all types can receive type AB plasma.

While donated blood is free, there are significant costs associated with collecting, testing, preparing components, labeling, storing and shipping blood; recruiting and educating donors; and quality assurance. As a result, processing fees are charged to recover costs. Processing fees for individual blood components vary considerably. Processing fees for one specific component also may vary in different geographic regions. Hospitals charge for any additional testing that may be required, such as the crossmatch, as well as for the administration of the blood.

Blood availability refers to the overall supply nationally or regionally. The blood supply varies among the many regions throughout the U.S. The blood supply level also fluctuates throughout the year. Factors impacting blood inventories often include holidays/travel schedules, inclement weather and illness, such as the outbreak of COVID-19. Historically, blood collections can be slow during the winter and summer months. A reduction in donor turnout rapidly impacts our nation's blood inventory.