A surprisingly long list of factors can stop you from donating plasma, ranging from basic requirements like age and weight to specific medications, medical conditions, recent travel, and even a new tattoo. Some disqualifications are permanent, but most are temporary deferrals that lift after a waiting period. Here’s a full breakdown of what might keep you from the donation chair.
Basic Eligibility Requirements
You must be at least 18 years old and weigh a minimum of 110 pounds. There’s no wiggle room on either number. If you’re under 110 pounds on the day you show up, you’ll be turned away regardless of how close you are.
Before every donation, staff will check your blood pressure and pulse. Your systolic blood pressure (the top number) must fall between 90 and 180, and your diastolic (the bottom number) must be between 50 and 100. Your pulse needs to be regular and between 50 and 100 beats per minute. If you’re outside those ranges on donation day, perhaps because of stress, caffeine, or a skipped medication, you won’t be cleared. You can usually try again another day once your vitals are within range.
Conditions That Permanently Disqualify You
Certain medical conditions result in a lifetime ban from donating plasma. These exist because the conditions either pose a direct risk to anyone who receives the plasma or because screening tests aren’t reliable enough to guarantee safety.
- HIV infection: Anyone who has ever tested positive for HIV or taken any medication to treat HIV is permanently ineligible.
- Hepatitis B or C: A past diagnosis or positive test for either virus is a permanent disqualification, even if you’ve been treated and cleared the virus.
- Blood cell cancers: Leukemia, lymphoma, and myeloma disqualify you for life, even if you’re currently cancer-free.
- Ebola virus: A history of Ebola infection is a permanent deferral due to the risk of persistent infection.
- Congenital bleeding disorders: Conditions like hemophilia result in permanent denial.
Medications That Require a Waiting Period
Many common medications trigger a temporary deferral. The waiting periods vary widely depending on how long the drug stays active in your body and what risk it could pose to a plasma recipient.
Blood thinners carry some of the shortest deferrals. Most newer oral blood thinners require just a two-day wait after your last dose, while warfarin and heparin require seven days. Anti-platelet medications used after heart procedures have waiting periods ranging from 2 to 14 days depending on the specific drug.
Isotretinoin, the powerful acne medication sometimes known by the brand name Accutane, requires a one-month wait. Finasteride and dutasteride, used for hair loss and prostate symptoms, each require a six-month deferral. These drugs can cause birth defects, and plasma products could theoretically expose a pregnant person to trace amounts.
Some medications trigger much longer deferrals. Drugs used to treat psoriasis, certain types of arthritis, relapsing multiple sclerosis, or basal cell skin cancer can require waiting periods of two to three years. Immunosuppressants generally require at least six weeks. If you’ve taken any medication for HIV prevention (PrEP or PEP), you’ll need to wait three months for oral versions or up to two years for injectable forms. Experimental medications carry a 12-month deferral.
Pregnancy and Postpartum
You cannot donate plasma while pregnant. After giving birth, the general recommendation is to wait at least six months. Some donation centers extend that timeline and ask you to wait until you’ve finished breastfeeding entirely. The reason is that pregnancy causes significant shifts in your blood volume and protein levels, and your body needs time to fully recover before plasma collection is safe for you.
Recent Vaccines
Whether a vaccine delays your donation depends on what type it is. Live vaccines, which contain a weakened version of the actual virus, require the longest waiting periods. The MMR vaccine (measles, mumps, rubella), chickenpox vaccine, and shingles vaccine each require a four-week wait. The oral polio vaccine, measles-only vaccine, mumps-only vaccine, yellow fever vaccine, and oral typhoid vaccine require two weeks. A smallpox vaccination carries an eight-week deferral.
Most inactivated vaccines, including the flu shot, tetanus, HPV, injectable polio, RSV, and common travel vaccines like injectable typhoid and Japanese encephalitis, have no waiting period at all. You can donate the same day as long as you feel well. The hepatitis B vaccine is an exception among non-live vaccines, requiring a 14-day wait when given preventively.
Tattoos and Piercings
A new tattoo is fine in most states as long as it was done at a state-regulated facility using sterile, single-use needles and fresh ink. If you got your tattoo in a state that doesn’t regulate tattoo shops, you’ll need to wait three months. Body piercings follow a similar rule: if a reusable piercing gun or any non-single-use instrument was used, or if there’s any doubt about the equipment, you’ll need to wait three months.
Travel to Malaria-Risk Areas
If you’ve recently traveled to an area where malaria is present, you’ll be deferred for three months after your return. The rules are stricter if you actually lived in a malaria-endemic region: former residents must wait three years before donating. Anyone who has been diagnosed with and treated for malaria faces a three-year deferral from the end of treatment, provided they’ve had no recurring symptoms during that time.
Day-of-Donation Screening Failures
Even if you meet every other requirement, you can still be turned away based on your screening results on the day of your appointment. Donation centers test your blood’s protein levels and hematocrit (the percentage of your blood made up of red blood cells) at every visit. If your protein is too low, it signals that your body hasn’t fully replenished from a previous donation. If your hematocrit is off, the machine separation process could leave you feeling faint or unwell.
Dehydration is one of the most common reasons people fail the day-of screening. It concentrates or dilutes your blood values in ways that push them outside the acceptable window. Eating a protein-rich meal and drinking plenty of water in the hours before your appointment gives you the best chance of passing. A poor night’s sleep, skipped meals, or recent illness can also tip your numbers just enough to get you deferred for the day.
Donation Frequency Limits
Federal regulations cap how often you can donate plasma. Most centers allow two donations within a seven-day period, with at least one day between sessions. If you’ve already hit that limit, you’ll be turned away until enough time has passed. These frequency rules exist to protect your own health, giving your body enough time to rebuild the proteins and fluid volume removed during each collection.