The process of donating blood is carefully regulated to safeguard the health of both the donor and the recipient. Regulatory bodies, such as the Food and Drug Administration (FDA), establish strict eligibility standards based on scientific evidence. These rules ensure the purity and safety of the blood supply by screening for factors that could transmit disease or compromise a donor’s well-being. Determining who can donate involves a detailed screening process examining a person’s general health, medical history, and recent activities.
Foundational Eligibility Criteria
Potential donors must meet several universal criteria for whole blood donation before a detailed health history is taken. Donors must be in good general health and feeling well on the day of the appointment. This includes having stable vital signs, such as a regular pulse, a temperature no higher than 99.5°F (37.5°C), and acceptable blood pressure readings.
A minimum age requirement is typically 17 years old, though 16-year-olds may be eligible with parental consent depending on local regulations. Donors must weigh a minimum of 110 pounds for all whole blood donations. This weight minimum ensures the volume of blood collected does not exceed a safe percentage of the donor’s total blood volume, protecting the donor from adverse reactions. Before the donation, a small blood sample is tested to confirm the donor’s hemoglobin level meets the minimum threshold (generally 12.5 g/dL for women and 13.0 g/dL for men), ensuring the donor does not become anemic.
Indefinite Deferrals Based on Medical History
Certain medical conditions result in an indefinite deferral from blood donation because they present a long-term risk of disease transmission to the recipient. An indefinite deferral means the person cannot donate blood for an unspecified period, though it allows for future eligibility if regulations change. A definitive positive test for transfusion-transmissible infections, such as HIV, Hepatitis B, or Hepatitis C, immediately results in this deferral, as the risk of transmission is unacceptable.
Individuals with a history of specific cancers are often indefinitely deferred, particularly those involving blood cells (leukemia, lymphoma, Hodgkin’s disease, and multiple myeloma). Donors who have had non-blood-related cancers, such as basal cell or squamous cell skin cancers, may be eligible once the cancer has been completely removed and healed. A history of intravenous drug use that was not medically prescribed is also a condition for indefinite deferral due to its association with a higher risk of blood-borne pathogens. Additionally, certain high-risk behaviors, such as receiving a dura mater transplant or past exposure to human growth hormone, historically led to deferral due to the risk of transmitting Creutzfeldt-Jakob Disease (CJD).
Temporary Deferrals Due to Recent Activity
Many deferral reasons are temporary, requiring a waiting period because the associated risk diminishes over time. A common temporary deferral is due to recent illness; a donor must wait until they are free of cold, flu, or fever symptoms for at least 24 hours to ensure they are fully recovered. Specific vaccinations, particularly those containing live-attenuated viruses, require a waiting period, which can range from two to four weeks, to ensure the vaccine’s components have cleared the bloodstream.
Recent travel to areas where vector-borne diseases are endemic, such as malaria or Chagas disease, necessitates a temporary deferral to allow for the pathogen’s potential incubation period. For instance, travel to a malaria-endemic region often results in a three-month waiting period after returning. Receiving an allogeneic blood transfusion results in a three-month deferral to mitigate the risk of disease transmission.
A three-month waiting period is required following a new tattoo, permanent makeup, or body piercing unless the procedure was performed in a state-regulated facility using sterile, single-use needles. Individuals who have recently completed treatment for syphilis or gonorrhea are deferred for three months. Certain medications, such as antibiotics for an active infection, require a donor to wait until the course of treatment is completed and the underlying infection has resolved.
Requirements for Platelet and Plasma Donations
Donating specific blood components like platelets and plasma is done through apheresis, which has additional eligibility requirements beyond those for whole blood. During apheresis, the donor’s blood is drawn and separated by a machine; the desired component is collected while the remaining blood parts are returned to the donor. This procedure is longer than a whole blood donation, often taking between one and two hours, and requires stable, accessible veins.
Apheresis donors can donate more frequently than whole blood donors, with platelet donations permitted as often as every seven days, up to 24 times within a 12-month period, because red blood cells are returned to the body. Apheresis donors must meet specific blood component counts; for platelet donation, the pre-donation platelet count must be at least 150,000 platelets per microliter. A distinction for platelet donation concerns anti-platelet medications, like aspirin, which irreversibly impair platelet function for their lifespan.
Consequently, taking aspirin or similar anti-platelet drugs requires a temporary deferral, typically two days, before donating platelets. These medications do not usually defer a person from donating whole blood or plasma. The deferral ensures that the collected platelets are fully functional and capable of contributing to blood clotting.