Plasma is the pale yellow, liquid component of blood, making up over half its total volume. This fluid transports red and white blood cells throughout the body. Plasma is rich in proteins, including clotting factors, albumin, and immunoglobulins, which are necessary for treating serious medical conditions such as bleeding disorders, immune deficiencies, and severe burns. Understanding the specific rules for plasma donation, especially concerning the common O positive blood type, helps clarify how individuals can contribute to this vital supply.
O Positive Eligibility for Plasma Donation
Individuals with O positive blood are generally eligible to donate plasma. This blood type is the most frequently occurring, present in approximately 37% of the U.S. population. While O positive plasma is valuable for manufacturing plasma-derived therapies, donors are often encouraged to donate whole blood or red blood cells instead. This preference exists because O positive red blood cells can be transfused to patients with any positive Rh factor blood type (A+, B+, AB+, and O+). Since O positive red cells are widely compatible, they are in constant high demand for transfusions, which is why donation centers prioritize whole blood donation from this group.
Why Plasma Donation Rules Differ by Blood Type
Blood types matter for plasma donation due to the presence of antibodies, which differs from red blood cell compatibility rules. Blood typing is determined by antigens, which are protein markers on red blood cells. Plasma contains antibodies that attack foreign antigens. A person with O positive blood lacks A or B antigens on their red cells, but their plasma naturally contains both anti-A and anti-B antibodies. If O positive plasma is given to a patient with A, B, or AB blood, these antibodies will attack the recipient’s red blood cells, causing a dangerous reaction. This incompatibility prevents O positive plasma from being universally used in transfusions. Conversely, the universal plasma donor is the AB blood type. AB plasma lacks both anti-A and anti-B antibodies, allowing it to be safely given to recipients of any ABO blood type. This scientific difference explains why AB donors are heavily recruited for plasma donation.
General Requirements for Plasma Donors
Beyond blood type, all plasma donors must meet standard health and logistical requirements to ensure donation safety and quality. Donors must be at least 18 years old and weigh a minimum of 110 pounds. These minimums ensure a safe procedure, as the volume collected is proportional to the donor’s body weight. Each donor must undergo a medical screening, including a physical examination, a confidential review of health history, and blood tests for protein and iron levels. Donors are also tested for infectious diseases such as HIV and Hepatitis. Individuals who have received a tattoo or piercing within the last four months are temporarily deferred from donating plasma.
Donation Frequency and Documentation
Plasma donation uses a process called apheresis to separate the plasma and return the other blood components. Guidelines allow for up to two donations within a seven-day period, with a minimum of 48 hours between donations. First-time donors are required to bring:
- Valid photo identification.
- Documentation proving their Social Security number.
- Proof of their current address.