Blood Donation: Eligibility, Process, and What to Expect

Blood donation is a simple, closely supervised, and safe act for most healthy adults. In the United States there is no single national blood service; instead, the American Red Cross, Vitalant, and community blood banks collect, test, and distribute blood to hospitals under standards set by the FDA and accreditation from the AABB.¹² Donated blood treats people with anemia, cancer, and blood disorders and keeps surgery, trauma care, and childbirth possible — everyday needs that depend entirely on volunteers.³ Roughly every two seconds someone in the U.S. needs blood, and it cannot be manufactured.¹ This guide explains who can donate blood, the requirements, the donation process step by step, and what to do afterward. It builds on our blood type hub; for who can receive which blood, see universal blood donor and blood transfusion.

Key takeaways

• To donate whole blood in the U.S. you generally must be in good health, weigh at least 110 lb (50 kg), and be 17 (or 16 with parental consent in many states); there is no upper age limit for healthy donors.¹
• A quick mini-physical checks temperature, pulse, blood pressure, and hemoglobin — at least 12.5 g/dL for women and 13.0 g/dL for men — before every donation.¹
• In 2023 the FDA moved to individual, gender-neutral risk assessment, replacing the earlier time-based deferral for men who have sex with men; the same questions now apply to everyone.⁴
• Whole blood can be donated every 56 days (up to 6 times a year); Power Red every 112 days, platelets as often as every 7 days, and plasma every 28 days.⁵
• The actual draw takes about 8–10 minutes; the whole visit runs about an hour with registration, screening, and refreshments.¹
• All blood types help, but O-negative — the universal donor — and rare types are always in the highest demand.⁵

Who can donate blood (US eligibility)

The core blood donation requirements for a whole-blood donation are broadly consistent across U.S. blood centers:¹⁶

• Age: at least 17 in most states, or 16 with a signed parental-consent form where state law allows; there is no upper age limit as long as you are healthy and meet the other criteria.
• Weight: at least 110 lb (about 50 kg). Donors under 18 may need to meet additional height-and-weight thresholds that protect younger, smaller donors from feeling faint.
• General health: you should feel well on donation day, with no active infection, fever, or cold or flu symptoms.
• Hemoglobin: a fingerstick must show at least 12.5 g/dL for women and 13.0 g/dL for men; too low a level defers you that day to protect your own iron stores.¹
• Interval: you must have waited long enough since your last donation (see intervals below).

Many other situations don't ban donation but postpone it (a "deferral"). Common temporary deferrals include:¹⁷

• Recent travel to areas with malaria or certain other infections, which can defer you for months.
• A recent tattoo or piercing done in a state that does not regulate its facilities — a 3-month wait; tattoos from state-regulated, licensed shops usually carry no deferral.
• Recent illness, fever, some antibiotics, or recent dental work.
• Pregnancy — you generally must wait about 6 weeks after giving birth.
• Certain medications or specific medical histories, reviewed one-on-one at check-in.

Because criteria change, the health-history interview at the donation center is where eligibility is decided case by case; when unsure, check the donor center's website or call ahead.⁶

The FDA's individual risk assessment

Who can donate blood in the U.S. is ultimately governed by FDA donor-eligibility rules, and those rules changed meaningfully in 2023. The FDA finalized guidance recommending that centers assess donor eligibility with individual, risk-based questions applied equally to everyone, retiring the previous time-based deferral for men who have sex with men (MSM) and their partners.⁴

Under the current approach, all prospective donors answer the same gender-neutral questions. A donor is deferred if, in the past 3 months, they have had a new sexual partner or more than one partner and have had anal sex — the combination linked to a window-period risk of undetected HIV. People taking medicines to treat or prevent HIV, including PrEP and PEP, are also deferred while on them.⁴ Importantly, the FDA stresses that no one should stop a prescribed medication such as PrEP or PEP in order to donate.⁴

Every unit collected is still tested for HIV, hepatitis B and C, syphilis, and other transfusion-transmissible infections, so screening questions and laboratory testing work together to protect the recipient.⁷

Types of donation and how often

Beyond a standard whole-blood donation, U.S. centers offer apheresis donations, in which a machine separates and keeps only one component and returns the rest to you. Each type has its own recovery interval:⁵

Intervals exist mainly to protect the donor. Each whole-blood donation removes a meaningful amount of iron (bound to the hemoglobin in the red cells you give), so donating too often can lower iron reserves and, over time, cause deficiency — which is why the interval and annual caps exist.⁸ Ferritin, the marker of iron stores, is the number that reflects this; Power Red donors, who give twice the red cells, wait the longest between donations.⁵ Premenopausal women, who tend to start with lower reserves, should be especially mindful.

The donation process, step by step

A whole-blood donation follows four steps and takes about an hour end to end:¹³

1. Registration. You sign in, show ID, and read materials about donation. First-time donors create a donor record.
2. Health history and mini-physical. In a private interview you answer confidential questions about your health, travel, and risk factors, and a staff member checks your temperature, pulse, blood pressure, and hemoglobin with a quick fingerstick. This screening is a key safety barrier for both you and the eventual recipient.
3. The donation. You recline in a chair while a sterile, single-use needle collects about one pint of blood. The draw itself lasts only 8–10 minutes for whole blood; apheresis donations take longer because the machine cycles blood through a separator.
4. Refreshments and rest. You sit for 10–15 minutes with a snack and a drink before heading out, which helps you feel steady.

All collection equipment is sterile and used only once, so you cannot catch an infection from donating blood.⁷

How to prepare and what to expect after

A little preparation makes the visit smoother:¹³

• Hydrate well and eat iron-rich foods in the days before; have a normal meal beforehand — never donate on an empty stomach.
• Sleep well the night before and bring a photo ID and a list of any medications.
• Wear a shirt with sleeves that roll up easily.

Afterward, a few simple steps aid recovery:¹

• Drink extra fluids and eat within the next few hours.
• Avoid heavy lifting or strenuous exercise for the rest of the day.
• Keep the bandage on for several hours and don't stand still for long stretches; if you feel lightheaded, sit or lie down and put your feet up.

Your body replaces the fluid volume within 24–48 hours, while red cells take a few weeks to fully rebuild — the biological reason behind the interval between donations. Some centers and clinicians suggest iron supplementation for frequent or younger donors to help replace the iron lost with each donation.⁸

Is donating blood safe?

For a healthy adult who meets the criteria, donating blood is very safe. The needle stick is brief, equipment is single-use, and serious complications are rare. The most common reactions are minor and short-lived — bruising at the needle site or a vasovagal reaction (feeling faint, lightheaded, or nauseated), which resolves quickly with rest, fluids, and a snack.⁷

Large studies confirm that varying donation frequency doesn't harm overall well-being, though giving more often comes at the cost of iron. In the INTERVAL randomized trial of over 45,000 U.K. donors, shortening the interval between donations collected substantially more blood with no major effect on quality of life — but at the price of more low-hemoglobin deferrals, lower iron stores, and more reported symptoms such as tiredness and dizziness.⁹ The trial's multi-year extension confirmed the same trade-off, underscoring why monitoring iron in regular donors matters.¹⁰ This is also why a randomized trial found that oral iron supplementation after donation markedly speeds recovery of hemoglobin and ferritin.⁸ The takeaway: healthy people can donate safely on the recommended schedule, and iron is the main thing to keep an eye on.

Have your labs explained by AI DiagMe

Before or after donating, a result such as hemoglobin or ferritin never means much on its own — it's the cross-reading of all your markers with your context that gives it meaning.

👉 AI DiagMe interprets your blood, urine, or stool results in plain language, taking your whole profile into account. It's an informational service that does not make a diagnosis and complements — never replaces — your physician's advice.

Frequently asked questions

Bottom line

Blood donation in the U.S. is open to most healthy adults who are 17 or older (16 with consent in many states), weigh at least 110 lb, and pass a quick hemoglobin check. A confidential health-history interview precedes every donation, and since 2023 the FDA applies gender-neutral, individual risk assessment to all donors. The draw takes just 8–10 minutes; afterward you hydrate, eat, and skip heavy exertion. Donation intervals protect your iron stores — a trade-off well documented by the INTERVAL trial. To continue the series, see blood type, universal blood donor, and blood transfusion.

Sources

Official U.S. sources and peer-reviewed studies (PubMed) used for this guide: