Feeling really ill after giving blood. - Thyroid UK

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Feeling really ill after giving blood.


Hi I gave blood on Thursday and haven’t been well since. As soon as I stand my blood pressure plummets 70/50 and I feel like my legs are going to collapse. Has anyone else had problems giving blood? They test your haemoglobin before your allowed to give blood. They drop blood into a solution and if it sinks you’re ok to give blood. Mine didn’t sink so she did an additional test and said I was fine to donate.

My symptoms are the same as being hypo but I was well before I donated so not sure if it’s due to my under active thyroid or the donation? Does anyone have any insight please? I’m not sure if I need to call the aftercare service or just wait it out?

19 Replies


I used to give blood many years ago, they don't want me any more as I'm a wreck :D . My father got his 50 pint badge and my son donates regularly. None of us experienced any problems.

I would call the aftercare service if I were you.

rosserk in reply to SeasideSusie

Thanks SSS. I was hoping it was the blood donation and not my thyroid. If things get any worse I will give them a call but for now I will assume it’s thyroid related 😭

It sounds like you have orthostatic hypotension & you need more fluid volume. Blood Centers will give salty treats like pretzels after donations to entice donors to drink more fluid, to replace the fluid volume they lost. Can you up your fluid intake? I have been reading some parts of the U.K. have been very hot. If that is the case where you are push fluids!

Blood Centers want you to call them after you donate if you do not feel well afterwards. They want to insure you were well at the time of donation, & continue to do well afterwards. They also want to insure the product(s) that are made from your donation are safe for the often very compromised recipients.

Your call should get answered by a trained Blood Bank Nurse who can advise you & refer any questions they may have to their blood bank’s doctors. The first line doctor answering nurse/donor questions at the blood bank I worked at was a retired surgeon & was very knowledgeable with these matters.

I am not familiar with the drop testing you mentioned for testing hemoglobin. We used German technology to test levels. If you think your hemoglobin is low treat yourself to a big steak if you are not a vegetarian. Hope you are feeling better soon.

rosserk in reply to Clarrisa

Clarissa thanks for the response. I think you might have a point I think I feel a little better later in the day after I’ve got plenty of fluid on board. I will keep drinking as much as I can. Yes the UK is having a bit of a heatwave, I’m in the midlands so very hot here! Kindest regards 💐


Personally I found I had to stop being donor. It upset my levels too much

It could be you are dehydrated in this heat

Best give someone a call

Thanks SlowDragon. I’ve just said to my husband I need to drink more fluids and his reply was ‘not sure that’s possible’. I drink gallons of flavoured water with ice, so a part of me thinks it’s unlikely my fluid levels are low. I gave blood because I was advised it would bring down my ferritin levels which were really high so it was for selfish reasons which I feel really bad about so probably right I’m suffering now!

I will see how I am tomorrow, I’m forever crying wolf and I’d be really embarrassed about causing an unnecessary fuss. In my mind it makes sense that giving blood would make us hypo but I’m new to all this so I don’t know anything for sure. I started feeling really weak with zero energy about an hour after donating so what ever is going on was definitely caused by the dip in blood volume. I read though that volume should return to normal within 24 hours so wasn’t expecting to still feel like this. 😭

Zephyrbear in reply to rosserk

Be very careful on your water intake... There is a condition known as Hyponatremia and it can kill. There have been some very highly publicised cases of dogs succumbing to this after playing in rivers and lakes on Twitter, but it can affect humans too. More details can be found here: webmd.com/fitness-exercise/...

You don't just need water. You need electrolytes as well. Go to a chemist or supermarket

and buy a couple of boxes of rehydration salts like Dioralyte or an own brand product.

Take a sachet mixed in a glass of water every 2 - 3 hours, including when you first get up and just before you go to bed.

If you can't find what you need at a supermarket you can make your own if you have the ingredients - it won't taste as nice as the commercial ones though. Do a search for "oral rehydration salts" or "oral rehydration therapy".

Thanks HumanBean that’s a great idea! I have some dioralyte I will take some now. 💐

It’s best to always call blood care if you have any problem after donating.

I had to call after my last one because I came up in a rash around the site. They take note and ask lots of questions to make sure you are well.

Blood donors are valued immensely.

My next donation will be my gold badge and I was thinking about giving up but I’m not sure my conscience will let me.

rosserk in reply to Ellie-Louise

Hi Ellie Louise thanks for the response. Well done on the gold badge that’s an amazing achievement! 🥇

I’m still not 100% sure it’s the blood donation that’s causing the problem. I’ve had this happen before when I was under medicated although I don’t think that’s the case this time it’s possible I’m now over medicated because my TSH was 0.011 although my T4 and T3 were good. I’m not sure whether my symptoms are caused by that and the blood donation is a red herring. Or maybe I’m just making excuses not to bother the health service, I’m really confused.

I’m surprised they allowed you to donate blood. If you have a thyroid problem then any reduction in blood volume can cause serious problems. Your body is already struggling so if you remove a significant amount of blood volume it will not be able to cope. You may need to go to A&E and have fluid replaced intravenously. You will get a drop in blood pressure if volume is significantly reduced

rosserk in reply to Karen321

Hi thanks for your response. I telephoned the blood bank before making the appointment to check it was ok to give blood and they said it was absolutely fine and lots of hypothyroid patients give blood. I admit I was sceptical though for the reasons you mentioned.

My blood pressure is still dropping and I’m sweating profusely and feeling faint when I stand or try to move around but as long as I stay sat down with my feet up I feel ok. I’m not sure if it’s something I need to worry about or if I just need to take it easy for a few days. I read that it takes 24 hours for blood to return to normal maybe it’s a bit longer with hypos? I’m Going to send hubby off to get me some dioralyte I only had one sachet so a few more might help. 💐

Ellie-Louise in reply to rosserk

Plasma is replaced in 24 hours, but your red blood cells take weeks to return to normal.

That’s why they recommend 16 weeks between donations for women and 12 weeks for men.

Are you feeling any better now, rosserk ? Hope so.

rosserk in reply to humanbean

Hi HumanBean, I’m not feeling great. I’ve got a rash all over my legs. Managed to get an emergency appointment on Monday with the Doctor who thinks it’s vasculitis, they were concerned about sepsis but though unlikely. She took a blood test for emergency analysis and I’ve just had a call to say my liver function has come back abnormal and they want to retest me. They’ve asked if I’m taking over the counter supplements and I have to ring later with a list of what I’ve been taking. I.e selenium, D3, inositol etc.

They can’t give me an appointment for the blood test yet I have to ring this afternoon to see if they have any appointments and I can’t speak to a Doctor about the abnormal test until Monday morning! I’m terrified by what’s going on and I will be a basket case by Monday! I can’t believe they can do this!

Hello, Just scrolling through and I see you have EDS also. Have you been investigated for Pots? It is common in people with EDS...but you may know that already! low blood volume can be present. Maybe something worth investigating 😃

rosserk in reply to snowflake

Hi Snowflake thank you for taking the time to respond to my post. Yes I have a diagnosis of POTs. It transpires there was a problem with my liver enzymes which were three times the normal range. I had an emergency liver scan which was normal. I had to repeat the tests after 2 weeks which should the enzymes were coming down by the 4th week they were back in the normal range but no explanation as to what caused the spike.

I’ve been referred back to my rheumatologist because I also have sjogrens which can effect the liver, hopefully I will get some answers then but somehow I doubt it. 💐💐

snowflake in reply to rosserk

So sorry to hear. I'm hypo and also have POTs so thought I'd mention it as the first thing they did was try and increase my blood volume and I'd read some people struggle when giving blood, also with the EDS. So far no change to my symptoms but hopefully you feel better soon. Good luck!

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