Don’t Donate Blood for a Month if You’ve Been Exposed to Zika

The Food and Drug Administration (FDA) is urging people who’ve returned from places where the Zika virus is active to refrain from donating blood for at least a month, while also recommending against the collection of blood from any region with active transmission.

Source: Don’t Donate Blood for a Month if You’ve Been Exposed to Zika

Delay for at least 4 weeks, but if in doubt – take more time rather than less.

15 Things You Probably Didn’t Know About Blood

Does menstrual blood really attract bears? Why does blood look blue in your veins? And why were the first blood transfusions performed with animals? Here are 15 facts, historical and biological, you probably didn’t know about blood.

Source: 15 Things You Probably Didn’t Know About Blood

The reason horseshoe crab blood is blue is the binding agent is copper, not iron. This species is thought to be the most “ancient”, having seen Jurassic dinosaurs come and go.

After I Receive a Blood Transfusion, When Does that Blood Physiologically Become Mine?

Functionally, it remains the same.

Prior to the transfusion, tests for cell surface antigens on the donor and recipient red blood cells (RBCs) would be done to ensure no differences are present that might cause a transfusion reaction.

Both the donor blood and the recipient blood have the same oxygen-carrying properties, so from a blood-draw standpoint it all just looks like blood. In most cases, the transfused blood is also a very small part of the body’s total blood volume, and so any differences between it and the rest of the body will be nearly undetectable in your average blood draw. Of course, if there are blood type mismatches, you would see reactions between donor blood and recipient blood, but barring that, everything would be kosher. Finally, the life of red blood cells is about 120 days, and in most transfusions, the transfused blood is completely absent from the system within 60 days.

One interesting side effect can happen in the event of massive transfusion that replaces an incredibly large volume of blood. If the volume is large enough to essentially replace the patient’s own blood, then you can get something called “dilutional thrombocytopenia” since transfused blood has platelets that aren’t fully functional. This can be corrected with further transfusions, but it’s something that might actually show up in a blood draw.

What would happen if a DNA test were performed on your blood after a transfusion?

Nothing special.  Tranfused blood (meaning RBCs) doesn’t carry DNA – it is essentially saline and RBCs.  Only a minimal amount of liquid (I don’t know the composition) is added to maintain pH and osmolarity so that the RBCs aren’t destroyed.

Blood that is routinely donated is then prepared in a way that removes >99% of white blood cells (the only thing in your blood to contain DNA) and the plasma. So, really, a blood transfusion is usually an erythrocyte transfusion.

However when someone has a bone marrow (or organ) transplant, all of the blood cells created from that point (IE: white blood cells) carry the DNA of the donor, not the recipient. They never really become the recipient’s.  Yes, DNA confusion has happened.

What happens if you put the wrong blood type in to someone?

The immune system will recognize it as a foreign object and destroy it, the same way it would an agent of illness like a pathogenic bacteria. Different blood types have different antigen markers on them (which is what the letter and +/- represent), and your body will attack blood that has the wrong markers. Type O blood lacks antigen markers, which is why it’s the universal donor, while AB blood has both making it the universal acceptor (the immune system is used to all the antigen markers).

Scientists Urge Caution in Wake of “Transmittable” Alzheimer’s Claim

A provocative new paper published in Nature suggests that neurodegenerative disorders such as Alzheimer’s and Parkinson’s may be transmissible through certain medical procedures. It’s an alarming claim—but one that will require more proof if it’s to be accepted by the scientific community.

Source: Scientists Urge Caution in Wake of “Transmittable” Alzheimer’s Claim

We already know prion disease can be transmitted via surgical instruments. The supposition is prion diseases are more common and responsible for more neuro-pathology than we have given them credit for. There is no data or evidence – especially not a study of 8 patients who suffered from an incredibly rare neurodegenerative disorder which we don’t fully understand, to support this.

Study: Fresh or Old Blood for Transfusions, Doesn’t Matter

Freshly donated blood is not better than older blood when it is transfused into severely ill patients, a new Canadian-led study reports.

The findings will be a relief to blood collection agencies, which have faced calls to shorten the length of time blood can be stored before it is transfused. In fact, Canadian Blood Services said they were very pleased with the outcome.

“The study supports our current inventory management practices for helping patients receiving transfusions in the intensive care setting,” said Dr. Dana Devine, the agency’s chief medical and scientific officer.

Currently blood can be stored for up to 42 days, though most transfusions involve blood that is about three weeks old. But there has been a growing belief that fresher is better.

Source: Fresh blood no better for transfusions in very ill patients: study

This news builds on a previous study in 2008.  Red blood cells last around four months.  White cells and platelets are quite a bit less.

That said, donations are still necessary.  If you can, please donate and encourage others to do so.  Some have found out they have a rare blood group, and the logistics around this are staggering.  But if you train, be aware of what you should do about donating without impacting your routine.

The Logistics of Sharing Rare Blood

Some 160 of the 342 blood group antigens are ‘high-prevalence’, which means that they are found on the red blood cells of most people. If you lack an antigen that 99 per cent of people in the world are positive for, then your blood is considered rare. If you lack one that 99.99 per cent of people are positive for, then you have very rare blood.

If a particular high-prevalence antigen is missing from your red blood cells, then you are ‘negative’ for that blood group. If you receive blood from a ‘positive’ donor, then your own antibodies may react with the incompatible donor blood cells, triggering a further response from the immune system. These transfusion reactions can be lethal.

Source: Inside the Science of Sharing Rare Blood

Similarly, there are rare people born with reversed organs and such.  The word had been that if you are a rare case, China would likely have someone with the same issue given the population size.  India would be another likely source…

Knowing that frozen blood has a 48-hour lifespan, compared to four weeks for fresh blood, makes me understand why there are constantly blood drives.  But the last time I checked, those on blood thinners are not allowed to donate.  If you can, please consider donating or encouraging those who can to donate blood.

Related: How Many Undiscovered Blood Groups Are There?