The requirement to not donate plasma when a bruise is present is a safety precaution. Plasma donation, or plasmapheresis, involves inserting a large-gauge needle into a vein to draw blood, separate the plasma, and return the remaining blood components. A visible bruise at or near the venipuncture site signals a potential complication that could be worsened by the procedure, leading to an automatic deferral by the donation center.
The Core Reason: Protecting the Donor’s Vein Health
A bruise, medically known as a hematoma, is a collection of blood that has leaked out of a damaged blood vessel into the surrounding tissue. This leakage indicates that the vein wall has been compromised, likely from a previous needle stick or trauma. Puncturing an already damaged or weakened vein significantly increases the risk of a more severe complication for the donor.
The large needles used in plasmapheresis pose a greater threat to a vein with compromised tissue integrity. Re-inserting a needle near a hematoma can cause the vein to “blow,” leading to a much larger, more painful bruise that takes longer to heal. This could also increase the chance of irritating or damaging adjacent nerves, which lie close to the veins in the antecubital fossa.
Bruises as Indicators of Systemic Health Issues
Beyond the local injury, a visible bruise serves as a simple physical indicator that the body’s clotting mechanisms may not be fully functional. The formation of a hematoma after a minor injury suggests that the donor’s ability to stop bleeding is impaired or that their capillaries are unusually fragile. The plasmapheresis process involves continuous blood flow and the use of an anticoagulant to prevent clotting in the machine.
Unexplained or excessive bruising can signal an underlying condition that affects donor suitability, such as thrombocytopenia, a low platelet count, or a coagulation disorder. Many common medications, including aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), can impair platelet function and worsen bruising. The donation center must ensure that the donor’s body can reliably clot the vein puncture site once the needle is removed.
Deferral Protocol and When You Can Donate Again
The deferral protocol ensures the venipuncture site has completely healed before attempting another donation. Generally, a donor is deferred until the bruised area is fully resolved, meaning the skin color has returned to normal and there is no residual tenderness or swelling. This healing process usually takes between one to two weeks, but the exact duration depends on the size of the hematoma.
To be re-eligible, the intended venipuncture site must be visually clear and free of any lumps, hardness, or signs of inflammation. If the bruise is only on one arm, some donation centers may allow the donor to use the opposite arm, provided that arm has a suitable vein and the center’s policy permits single-arm donation.