What makes it so you can't donate blood? A comprehensive guide

September 22, 2025 •

4 min read

Every two seconds, someone in the U.S. needs a blood transfusion. Understanding what makes it so you can't donate blood is crucial for protecting recipients and ensuring the blood supply remains safe, as eligibility is determined by strict medical and safety guidelines.

Quick Summary

Donor eligibility rules exist to protect both the donor and the patient, encompassing strict criteria related to health, recent travel, medications, and risk behaviors, which can lead to a temporary deferral or permanent ineligibility from donating.

Key Points

Permanent Conditions: Some conditions like HIV, specific cancers, or viral hepatitis B/C permanently prevent donation for safety.
Medication Restrictions: Certain medications, including some blood thinners and acne treatments, require a waiting period before donating.
Travel Impacts: Travel to areas with malaria risk may result in a temporary deferral. Older travel to some European countries was previously a concern for vCJD.
Tattoos and Piercings: A waiting period of three months is necessary if a tattoo or piercing was received in an unregulated facility to mitigate infection risk.
Risk Behavior Screening: Questions about lifestyle and risk behaviors, such as intravenous drug use or certain sexual activities, are crucial for ensuring the safety of the blood supply.
General Health: You cannot donate if you feel unwell, have a fever, or have an active infection like a cold or flu.

Protecting Patients and Donors

Blood donation is a selfless act that saves countless lives. However, maintaining the safety and integrity of the blood supply is a top priority. For this reason, strict eligibility criteria are in place to screen potential donors. These rules are designed to protect both the recipient from contracting bloodborne illnesses and the donor from health risks associated with the procedure. The reasons for deferral can range from temporary, such as a recent tattoo, to permanent, like a history of certain illnesses.

Health conditions that may prevent donation

Permanent medical deferrals

Certain medical conditions are considered permanent reasons for deferral, meaning an individual can never donate blood. These often relate to infectious diseases or severe health issues that could compromise the safety of the blood supply.

HIV Positive Test: A positive test for HIV is a permanent deferral.
Viral Hepatitis B and C: Testing positive for viral hepatitis B or C results in permanent ineligibility.
Certain Cancers: A history of specific cancers like leukemia or lymphoma is a permanent deferral. Eligibility for other cancers depends on the type, treatment, and recovery time.
Hemophilia: Individuals with hemophilia are permanently deferred due to clotting issues.
Creutzfeldt-Jakob Disease (CJD): A history of or risk factors for CJD or its variant (vCJD) leads to permanent deferral.

Temporary medical deferrals

Many conditions only require a temporary waiting period. These include acute illnesses, recovery from procedures, or manageable health issues.

Cold, Flu, or Infection: You must wait until fully recovered from a cold, flu, fever, or active infection. A waiting period is typically needed after completing antibiotic treatment.
Recent Surgery: Major surgery usually requires a waiting period for full recovery.
Pregnancy: Expectant mothers are deferred for a period after pregnancy, usually six weeks.
Blood Transfusion: Receiving a blood transfusion results in a temporary deferral.
High or Low Blood Pressure: Blood pressure outside the acceptable range on donation day will result in deferral for that day.

Medications and donor eligibility

Some medications can prevent donation due to potential impact on the donor or recipient. Do not stop prescribed medication to donate.

Medications that require deferral

Blood Thinners: Anticoagulants like warfarin require a waiting period after the last dose.
Acne Medications: Isotretinoin requires a one-month wait, and acitretin (for psoriasis) requires a three-year wait.
Hair Loss Medications: Finasteride requires a one-month wait, while dutasteride requires a six-month wait.
HIV Prevention Medications: PrEP and PEP medications require a waiting period.
Hepatitis B Immune Globulin: A waiting period is required if given to prevent hepatitis B.

Travel history and recent procedures

Travel or recent procedures can lead to deferral due to the risk of transmitting infectious diseases.

Malaria-Endemic Areas: Travel to high-risk malaria areas often requires a three-month waiting period.
European Travel (vCJD): Eligibility criteria have changed, but some residency periods in the UK or France may still apply, and specific deferrals may be in place for prior permanent deferrals.
Tattoos and Piercings: A three-month waiting period is typically required for tattoos or piercings received in unregulated facilities to mitigate infection risk. If done in a regulated, licensed facility with sterile needles, the deferral may not apply.

Risk behaviors and lifestyle factors

Screening includes questions about behaviors to ensure blood supply safety.

Needle Use: Anyone who has used needles to inject non-prescribed drugs is permanently deferred.
Sexual Activity: Recent FDA guidelines use individual risk assessment. A three-month deferral applies for individuals with new or multiple sexual partners and recent anal sex, or recent sexual contact with an HIV-positive person or someone who exchanges sex for money/drugs.

Summary of temporary vs. permanent deferrals

Here is a summary comparison of reasons for not being able to donate:


Reason	Temporary Deferral	Permanent Deferral
Infections	Active cold, flu, fever, or localized infection.	Confirmed HIV, Hepatitis B or C.
Medications	Certain acne meds (isotretinoin), blood thinners, HIV prevention meds.	History of taking etretinate (Tegison).
Medical History	Pregnancy, recent major surgery, blood transfusion within 3 months.	History of leukemia, lymphoma, or CJD.
Travel	Travel to malaria-risk regions within 3 months.	History of CJD risk exposure (country-specific).
Lifestyle	Recent tattoos/piercings (3 months in unregulated states), recent high-risk sexual contact (3 months).	Ever used needles for non-prescribed drugs.

Conclusion: Navigating eligibility for donation

Blood donation saves lives. The comprehensive screening process covers health, medications, travel, and risk behaviors to ensure blood supply safety. Understanding deferral reasons is important. If unable to donate, you can still help by volunteering or donating financially. Honest self-assessment is crucial for public health. For current eligibility rules, consult resources like the American Red Cross website.

Frequently Asked Questions

If you have a cold or other respiratory infection, you must wait until your symptoms are completely gone and you feel well again before donating. This is to ensure you are healthy and to prevent the risk of passing on an infection.

It depends on where you got the tattoo. In most states, if you received a tattoo from a state-regulated facility using sterile needles, you can donate immediately. If you received it in a state that does not regulate tattoo parlors or from an unlicensed artist, you must wait three months.

No, most common over-the-counter medications and many prescription drugs do not prevent donation. However, certain drugs, such as blood thinners, specific acne medications, and HIV prevention medication, require a waiting period.

A positive test for HIV leads to a permanent deferral because the virus is a bloodborne pathogen that can be transmitted through transfusion. This policy is in place to completely eliminate any risk to the blood recipient.

Travel to certain countries or regions with a high risk of infectious diseases, such as malaria, requires a temporary waiting period. This is to ensure the donor has not contracted and is not carrying the illness.

In most cases, having diabetes (type I or II) does not prevent you from donating blood, as long as you are feeling well and your diabetes is under control. It is always best to consult with the blood donation center for specific guidelines.

Current FDA guidelines focus on individual risk assessment rather than gender or sexual orientation. A temporary three-month deferral is now based on specific risk behaviors, such as recent sexual contact with new partners involving anal sex.