Why would I not be allowed to donate blood?: Common Reasons for Deferral

September 30, 2025 •

4 min read

Every two seconds, someone in the U.S. needs a blood transfusion, but not everyone can donate due to strict safety guidelines. The most common deferrals protect both the donor and the recipient, so understanding why would I not be allowed to donate blood? is key to a successful donation experience. These rules, set by organizations like the FDA and AABB, ensure the blood supply remains as safe as possible for patients.

Quick Summary

This guide details the various reasons, both temporary and permanent, for being deferred from blood donation. It covers medical conditions, recent infections, certain medications, specific travel histories, lifestyle factors, and vital statistics to help potential donors understand eligibility criteria.

Key Points

Low Hemoglobin is a common cause: Low iron levels can cause a temporary deferral, particularly for women, to ensure the donor’s health is not compromised.
Recent Travel can result in deferral: Travel to areas with a high risk of mosquito-borne illnesses like malaria or Zika can trigger a temporary deferral period.
Medication History is Important: Certain medications, including some acne treatments, blood thinners, and HIV prevention drugs, require specific waiting periods before you can donate.
Not all deferrals are permanent: Many reasons for deferral are temporary, and once the waiting period ends, donors are encouraged to try again.
Lifestyle factors are considered: Factors like recent tattoos or piercings and high-risk behaviors related to bloodborne infections can lead to deferral.
Chronic illness can lead to permanent deferral: A history of certain conditions like viral hepatitis B/C, HIV, and specific cancers results in permanent disqualification for patient safety.

The process of donating blood is a generous act that saves millions of lives each year. However, stringent eligibility rules are in place to protect the health of both the donor and the recipient of the blood products. Understanding these criteria is the first step for anyone considering a donation. Donor deferrals, whether temporary or permanent, are based on a series of health, travel, and lifestyle questions asked during a confidential medical screening.

Temporary Reasons for Blood Donation Deferral

Many donors are temporarily deferred, meaning they can donate again once a waiting period has passed. The duration of the waiting period depends on the specific reason.

General Health and Recent Procedures

Low Hemoglobin/Anemia: A potential donor will be temporarily deferred if their hemoglobin level is too low, a common reason for deferral, especially among women.
Active Illness: You must be in good health and feeling well on the day of your donation. This includes being free of colds, flu, sore throats, or other infections.
Recent Pregnancy and Childbirth: A waiting period of six weeks after giving birth is required.
Surgery: Recent major surgery can be a reason for deferral, with eligibility restored once the donor has fully recovered.
Blood Transfusion: Those who have received a blood transfusion in the past three months in the U.S. will be temporarily deferred.

Lifestyle and Travel

Tattoos and Piercings: In some states, a three-month waiting period is required after getting a tattoo or body piercing unless the procedure was performed at a state-regulated facility using sterile, single-use needles.
Travel to Malaria-Risk Areas: A temporary deferral is required for individuals who have recently traveled to or lived in areas with a high risk of malaria. The waiting period varies depending on the length of stay and country.
Zika Virus: Recent infection with or exposure to the Zika virus can result in a 120-day deferral from resolution of symptoms.

Medications

Oral HIV Prevention (PrEP/PEP): Certain oral medications for HIV prevention require a three-month deferral period.
Injected HIV Prevention (PrEP/PEP): The deferral period for injected PrEP is longer, at two years.
Acne Medication (Isotretinoin): A one-month wait is needed after the last dose of certain oral acne medications.
Anticoagulants (Blood Thinners): Depending on the specific medication, a wait of several days to a week may be necessary.

Permanent Reasons for Blood Donation Deferral

Certain conditions pose a permanent risk and result in indefinite deferral. These measures are critical for maintaining the safety of the blood supply.

Bloodborne Illnesses

Positive HIV Test: Any individual who has ever tested positive for HIV is permanently deferred from donating.
Viral Hepatitis B or C: A history of viral hepatitis B or C results in permanent ineligibility.
Ebola Virus: A history of Ebola virus infection is a permanent disqualification.

Chronic Conditions and Risk Factors

Certain Cancers: Individuals with a history of leukemia, lymphoma, or myeloma are permanently deferred, even if they are cancer-free. Some other cancer types have a temporary deferral period.
Congenital Bleeding Disorders: People with inherited blood-clotting diseases are not eligible to donate.
Non-Prescription Injection Drug Use: A history of using injected drugs not prescribed by a doctor leads to a permanent deferral.
Variant Creutzfeldt-Jakob Disease (vCJD): Historically, time spent in certain European countries during specific years resulted in deferral. While some restrictions have been lifted, a permanent deferral still applies to those with a history of vCJD risk exposure.

Comparison of Temporary vs. Permanent Deferral


Feature	Temporary Deferral	Permanent Deferral
Reason	Short-term health issue or recent exposure with a defined waiting period.	Indefinite health condition or irreversible risk factor.
Example Conditions	Cold, flu, low hemoglobin, recent tattoo, recent travel to malaria area, pregnancy.	Positive HIV or hepatitis B/C test, certain cancers, inherited bleeding disorders.
Action Required	Wait until the deferral period is over, then check eligibility again.	The individual cannot donate blood, ever.
Reversibility	Yes, after the specified waiting period.	No, the ineligibility is indefinite.
Frequency	More common than permanent deferrals.	Less common, but crucial for blood safety.

What to Do After Being Deferred

Being deferred can be disappointing, but it's important to remember that it's a safety measure. If you receive a temporary deferral, you can set a reminder to return and donate once the waiting period has passed. In the case of a permanent deferral, you can still support blood services by encouraging others to donate or volunteering with a local blood center. Blood donation centers are always grateful for the intent to donate, regardless of the outcome.

Conclusion

Understanding why a person might not be allowed to donate blood is crucial for ensuring a safe and efficient donation process. Whether due to temporary issues like illness and travel or permanent conditions like a history of viral infections, eligibility criteria are strictly enforced for the protection of both donors and recipients. A proactive approach, including checking eligibility criteria and preparing for your donation, can help ensure a positive experience for everyone involved. If you are uncertain about your eligibility, the best course of action is to contact your local blood donation center to discuss your specific situation with a medical professional.

For more detailed information on donor eligibility, you can consult the official Red Cross website, a reputable source on blood donation guidelines. https://www.redcrossblood.org/donate-blood/how-to-donate/eligibility-requirements.html

Frequently Asked Questions

No, you must be in good health and feeling well on the day of your donation. You cannot donate if you have a cold, flu, sore throat, or any other infection, including COVID-19.

Not necessarily. Your blood donor center will specify if your deferral is temporary or permanent. Many deferrals are temporary, and you can become eligible again after the waiting period ends.

It depends on the medication. Many common medications, such as those for blood pressure, are acceptable. However, certain drugs like blood thinners, some acne medications, and specific HIV prevention drugs require a waiting period.

For a tattoo or piercing, you must wait three months. This deferral period may be waived if the procedure was performed at a state-regulated facility using sterile, single-use needles.

In most cases, you must be at least 17 years old (16 with parental consent in some states) and weigh at least 110 pounds to donate whole blood.

It depends on where you traveled. A temporary deferral may be imposed if you visited an area with a high risk of certain infectious diseases, like malaria.

It depends on the type of cancer. A history of blood-related cancers like leukemia and lymphoma results in a permanent deferral. For other cancers, you may be eligible to donate once you are cancer-free and a specific waiting period has passed.