Plasma donation involves collecting the liquid portion of the blood, which contains valuable proteins, antibodies, and clotting factors. This collected plasma, known as Source Plasma, is then processed to create life-saving therapeutic products, such as immunoglobulins and treatments for hemophilia. Because these derivatives are administered to patients, the safety of the starting material is paramount. Regulatory bodies require plasma centers to implement rigorous and mandatory screening protocols for every donation to protect recipients from potential infectious agents.
Mandatory Infectious Disease Screening
Plasma centers operate under strict regulations set by the Food and Drug Administration (FDA) to ensure the safety of therapeutic products. These regulations mandate testing for evidence of infection from a specific panel of communicable disease agents for every donor and every donation. Screening focuses on the Human Immunodeficiency Virus types 1 and 2 (HIV-1 and HIV-2), Hepatitis B Virus (HBV), and Hepatitis C Virus (HCV). Additionally, all plasma donors must be tested for Treponema pallidum, the bacterium responsible for Syphilis.
Testing uses highly sensitive laboratory methods to detect both the virus and the body’s immune response. Nucleic Acid Amplification Testing (NAT) is employed to look for the genetic material (RNA or DNA) of viruses like HIV, HBV, and HCV. NAT detects infection earlier than traditional methods, often during the “window period” before the body produces detectable antibodies. This technology significantly reduces the residual risk of transmitting these infections.
Standard serological tests, such as Enzyme-Linked Immunosorbent Assays (ELISA), detect specific antibodies or antigens related to these infections. Centers combine these technologies because serological tests identify long-term exposure, while NAT catches recent infections. Centers may utilize minipool multiplex assays, where samples from multiple donors are tested together for several viruses simultaneously. If a minipool test is initially reactive, each individual sample is then tested separately to pinpoint the positive donor.
The Plasma Testing Procedure
The plasma testing process ensures product integrity before a donation is released for manufacturing. Every donation undergoes initial screening optimized to catch viral markers. A sample that yields a preliminary positive or “reactive” result is then subjected to a more specific, supplemental test to confirm the infection.
Source Plasma units are placed into quarantine storage immediately after collection, remaining frozen and unused for a designated period. Plasma from a first-time donor is never used for manufacturing and is destroyed if the donor does not return for a second negative test. Plasma is only considered a “qualified” unit and released after the donor provides at least two negative test results on samples collected at least 60 days apart.
If a donor’s sample tests reactive, the center initiates a mandated “lookback” procedure. This process requires the center to identify and quarantine any previously collected plasma units from that same donor. Lookback prevents the use of prior donations that may have been collected during the “window period” before the donor’s infection was detectable. This process ensures that only plasma from donors with consistently negative results enters the supply chain.
Managing Reactive Test Results
When a donor’s sample yields a repeatedly reactive result, the donor is permanently deferred from all future donations. This deferral is recorded in the National Donor Deferral Registry (NDDR), which lists individuals disqualified due to positive infectious disease testing. The specific plasma unit that tested reactive is immediately destroyed, along with any prior quarantined donations from that individual. Centers must notify the donor of the reactive result and provide appropriate counseling, including referral to a physician for formal medical diagnostic testing and treatment.
A reactive screening test does not always confirm an infection, as tests can occasionally produce a false positive result. Despite a subsequent negative confirmatory test, the initial reactive screening result still leads to permanent deferral for certain markers to maintain safety. The center must report the reactive result to regulatory bodies, even when a false positive is suspected.