Eli5: What’s the expiration date of blood once outside the body? (e.g. blood taken for tests donations) What about it’s components?

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Eli5: What’s the expiration date of blood once outside the body? (e.g. blood taken for tests donations) What about it’s components?

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I’ll have to rewatch that late scene in the movie Limitless to answer you. I’ll get back to you

I don’t know about whole blood, but this is what my Red Cross donor app (highly recommend downloading it) says about the components:

* Red cells for 42 days
* Platelets for up to 5 days
* Plasma and cryoprecipitate for one year

But honestly the blood shortage is so bad right now that nothing will get anywhere close to its expiration date before being used, even if you have one of the less universal blood types like B+ or something. The app lets you track your donation as far when processing starts, when testing starts, when storage begins, when it gets used, and which hospital used it. Not who it was used on though, for privacy reasons. My last donation was used within two weeks of being placed in storage.

Whole blood transfusions are less common because they are logistically more complicated. Wikipedia says 21 days but there wasn’t a citation.

Edit: also, since this post is getting some attention and I want to sell people on the concept, the app also has achievements like platelet donation, donating on a holiday, and sharing a blood selfie on social media. You can also see your COVID antibody results and your hemoglobin results. You can schedule appointments easily and do the pre-donation questionnaire from home on your phone to speed up the check-in process.

Depending on the test you are doing, and what you are trying to measure. For example, the measurement of electrolytes, specifically potassium (K+) becomes less reliable over just a few short hours due to most of the K+ being within your cells. And as time goes on and cells start to degrade, this K+ leaks out of the cells into the plasma, and thus giving you a falsely elevated K+ result.

The inverse is true of many proteins measured by different laboratories. Degradation over time. Other components of blood that become raised over time are phosphate and ammonia, and many others.

Another example is the measurement of serum glucose, obviously the body and cells use glucose as energy, so once the sample is out of the body, you want to be analysing that one quite quickly! But there are ways to get around it, and that is using sample tubes that are specially lined with a material that prevents this from occuring.

With haematology, and blood films, the morphology of the cells start to degrade over time, and you can see the misshapen cells, and leaking intracellular components. I ‘think’ some of this is down to the mixing with EDTA in some blood tubes, which is there to stop your blood clotting in the tubes, thus making them difficult to analyse.