You can be turned away from donating plasma for dozens of reasons, ranging from weighing under 110 pounds to taking certain acne medications. Some disqualifications are permanent, like a positive HIV test. Others are temporary deferrals that lift after a waiting period. Here’s a breakdown of the most common reasons people are found ineligible.
Age, Weight, and Basic Requirements
Federal regulations require plasma donors to weigh at least 110 pounds (50 kilograms). Most donation centers also require you to be at least 18 years old, though some states allow 16- or 17-year-olds with parental consent for whole blood donation. You’ll need a valid photo ID and a verifiable mailing address.
If you’ve had an unexplained weight loss of 10 pounds or more in less than two months, centers are required to flag that and refer you for a medical evaluation before allowing further donations. This screening exists because rapid unexplained weight loss can signal an underlying condition that would make donation unsafe for you or the recipient.
Hemoglobin and Protein Levels
Before every donation, staff will check your blood to make sure your body can handle the procedure. For hemoglobin, the iron-carrying protein in red blood cells, men need at least 13.0 grams per deciliter and women need at least 12.5. Women with levels between 12.0 and 12.5 may still qualify under an alternative screening process, but anything below 12.0 is a deferral. Low hemoglobin is one of the most common day-of reasons people get turned away, and it often comes down to diet, hydration, or menstruation.
For plasma specifically, your total plasma protein must fall between 6.0 and 9.0 grams per deciliter. This is checked before each plasmapheresis session. If your protein is too low, your body may not recover well from the donation. If it’s too high, it can indicate an underlying health issue.
Medications That Defer You
Several common medications will temporarily disqualify you, primarily because traces could harm a blood recipient, especially a pregnant woman or developing fetus.
The acne drug isotretinoin (sold as Accutane, Claravis, Zenatane, and other brand names) requires a one-month wait after your last dose. The hair loss and prostate medications finasteride and dutasteride carry a six-month deferral. Both categories cause birth defects, and even small amounts transferred through donated plasma could damage an unborn baby.
Blood thinners and anti-platelet drugs also trigger deferrals, though the wait times vary:
- 2 to 3 days for shorter-acting blood thinners like fondaparinux and prasugrel
- 7 days for warfarin and ticagrelor
- 14 days for clopidogrel (Plavix)
- 1 month for vorapaxar
Many other anticoagulants, including rivaroxaban, apixaban, and dabigatran, also result in deferral. If you take any blood-thinning medication, expect to be asked about it during screening.
Chronic Health Conditions
Some medical conditions result in a permanent deferral. You cannot donate plasma if you have ever tested positive for HIV, have been diagnosed with hepatitis B or hepatitis C, or are a hemophiliac. These are firm, lifelong exclusions because the risk of transmitting these infections or compromising the blood supply is too high.
Certain cancers also disqualify you, though this area is more nuanced. Some cancer survivors may become eligible again depending on the type of cancer, how long they’ve been in remission, and the policies of the specific collection center. If you’ve had cancer, you’ll likely need to discuss your history directly with the center’s medical staff.
Tattoos, Piercings, and Body Modifications
Getting a tattoo or piercing used to mean a full year before you could donate. That deferral has been shortened to three months in most cases. If your tattoo was done at a state-licensed facility using sterile technique, some centers in certain states (Louisiana, Texas, Alabama, Mississippi, for example) will clear you as soon as the site has healed, with no additional waiting period. Permanent makeup applied by a dermatologist has no deferral at all.
For ear and body piercings, the same three-month rule applies, unless the piercing was done with single-use equipment, in which case there’s no waiting period. Self-piercing and body branding still carry a full one-year deferral because the infection risk is significantly higher without professional sterile conditions.
Travel to Malaria-Risk Areas
If you’ve recently traveled to a region where malaria is present, you’ll face a three-month deferral from the date you returned. This was recently shortened from one year. If you used to live in a malaria-endemic area, the wait is longer: three years from the date you left. And if you were actually diagnosed with and treated for malaria, you must wait three years after treatment and remain symptom-free throughout that period before donating.
These travel deferrals exist because malaria parasites can survive in your bloodstream without causing noticeable symptoms, making it possible to unknowingly pass the infection to a transfusion recipient.
Pregnancy and Postpartum
You cannot donate plasma while pregnant. After giving birth, the standard waiting period is six weeks. This deferral protects both the parent and baby, since plasma donation temporarily reduces blood volume and protein levels that your body needs for recovery and, if applicable, breastfeeding.
Vaccines and Recent Illness
Live-attenuated vaccines, which use a weakened form of a virus, typically require a short deferral. Common examples include the MMR (measles, mumps, rubella) vaccine and the chickenpox vaccine. Inactivated vaccines like the flu shot generally don’t require any waiting period, though policies vary by center. If you received a vaccine recently and aren’t sure, bring the name of the vaccine to your screening appointment.
Active infections, fevers, and feeling generally unwell on the day of donation will also get you deferred. This includes colds, flu, and stomach bugs. Most centers ask you to wait until you’ve been symptom-free for a set period, often a few days to a couple of weeks depending on the illness.
High-Risk Behaviors
Donation centers screen for behaviors that increase the risk of bloodborne infections. Intravenous drug use that wasn’t prescribed by a doctor is a permanent deferral at most centers. Recent incarceration (typically 72 hours or more in a correctional facility) triggers a temporary deferral, usually three months to a year, because of the higher prevalence of bloodborne infections in those settings.
Sexual behavior screening criteria have changed significantly in recent years. The FDA moved away from blanket deferrals based on sexual orientation and now uses individual risk-based questions for all donors regardless of gender or partner gender. The specifics of these questions vary, but they focus on recent behaviors rather than identity.
What Happens if You’re Deferred
If you’re turned away at a plasma center, the staff should tell you why and whether it’s temporary or permanent. For temporary deferrals, you’ll typically be given a specific date when you can return. Some centers keep records across visits, so if you try to donate during a deferral period, their system will flag it.
Being deferred doesn’t necessarily mean something is wrong with your health. Low hemoglobin on a given day, a recent tattoo, or a trip abroad are all common, fixable reasons. If you’re repeatedly deferred for the same issue, like low hemoglobin, it may be worth looking into your iron intake or hydration habits before your next attempt.