Can You Donate Blood If You Consume Cannabis?

Blood banks have been going through tough times during the Covid-19 pandemic. Because of the lockdowns, self-quarantine and other limitations, donors can not donate blood as often as they did before. The World Health Organization (WHO) reported in 2020 that people may be less likely to donate blood due to social distancing or fear of contracting the virus, but that blood donation is necessary to save the lives of millions of people around the world every year, which is why donating blood is crucial, especially now.

So, can you donate blood if you smoke marijuana?

In short - yes. Cannabis use does not deprive a person of the right to donate blood. Medical organizations do not screen donated blood for the presence of THC (tetrahydrocannabinol) - the main psychoactive component of the cannabis plant.

According to the Red Cross' website “The use of cannabis does not disqualify an individual from blood donation, but potential donors cannot give if their use of cannabis impairs their memory or comprehension.” Most blood banks have the same rules and will refuse a potential donor if he is under the influence of cannabis, as well as alcohol and prescription drugs. Consumption of synthetic cannabis and Injecting any drugs will also disqualify you from being a donor.  

Now let us try and answer frequently asked questions regarding blood donation and cannabis.

When can you donate blood after using cannabis?

There is no precise data to tell you how long you should wait between using cannabis and donating blood. Thus, as long as you are not under the influence at the time of your blood donation appointment, the presence of THC in your system should not directly disqualify you. Although it is best to refrain from cannabis, caffeine and alcohol prior to donating.

It is hard to say how long exactly cannabis stays in a person's blood. It depends on numerous factors such as weight, age, metabolism, frequency of use, and more. If you are an occasional consumer, who lights up once a week or so, you will probably have no traces of THC in just 2 weeks. In any case, if you want to save someone's life and donate your blood, it is worth taking a break from marijuana for a couple of weeks.

Can a transfusion recipient fail a drug test if he receives blood from a cannabis user?

No. The science is complicated but peak THC levels in plasma happen within 10 minutes of use and then rapidly decline.

If the blood is not tested for THC, what tests are conducted?

Donor blood is tested for syphilis, HIV, hepatitis, and HTLV (human T-lymphotropic virus) which can cause a blood or nerve disease.

Can you smoke cannabis after giving blood?

People who smoke after donating blood may experience increased dizziness. Therefore, it is best to take it easy for a couple of hours after donating in order to avoid this.

What disqualifies you from donating blood or plasma?

These are the most common criteria that will prohibit you from becoming a donor but the list is much longer:

• Being under 17
• A piercing or tattoo done within the last year
• Pregnancy or recent childbirth
• Steroid use
• Weighing less than 110 pounds
• Having had leukemia, lymphoma, other blood cancers
• Any illness presenting with fever
• Low iron levels, which may signify anemia
• Having travelled to a malaria-risk country within the past 3 years
• Inherited blood clotting disorder
• HIV or hepatitis infection

There is always a shortage of whole blood and plasma donors, and the situation is worse due to the coronavirus pandemic, so if you ever considered becoming a donor, now might be the best time. Donating blood saves lives.

Health Disclaimer: The information provided in this article is for educational purposes only and should not be taken as medical advice. Always consult with a qualified healthcare provider before using cannabis, particularly if you have pre-existing conditions or are taking medication.