Best time for a blood test?

[KBird01]

Hi all,

I've ordered a comprehensive blood test from Medichecks, as I've been working on my ferritin levels amongst other things. (Obviously, I'll be ignoring the inevitable out of range B12 result! 😁)

Problem is, I had a mild tummy bug 3 days ago. My bloods appointment is for a week after this, so will I be OK to have the test by then? I believe that infections can cause some readings to read differently and don't want to waste my money if my results aren't reliable.

Any advice/info appreciated. 😊

[FlipperTD]

Scientist, not medic.

A tummy bug can result in fluid loss due to diarrhoea, and therefore dehydration. This can cause various other issues, which will resolve. This can also upset your potassium; one of the primary markers of folks who have 'laxative abuse' is disordered potassium.

Inflammatory conditions can affect the ferritin level.

Hope this helps!

[KBird01 in reply to FlipperTD]

Thank you FlipperTD . Do you know how long ferritin levels can be affected after inflammation has occurred. Tummy settled down by Thursday and blood test is booked for Monday.

[FlipperTD in reply to KBird01]

Sorry, but it's a 'how long is a piece of string' question! The response time will be very much an individual thing. Some inflammatory marker tests react very quickly, and others take much longer to go up and down. CRP [C-reactive protein] goes up very quickly, and comes down quickly too. The ESR [Erythrocyte Sedimentation Rate] goes up steadily, and comes down steadily too.

I wish I had the answer, but often, these markers continue to rise when we're on the mend as part of the immune response.

[KBird01 in reply to FlipperTD]

Thanks FlipperTD . I thought that might be the case, but now I officially know what I don't know! 😊

[FlipperTD in reply to KBird01]

I can send you a piece of string, or perhaps a length of elastic might be better... Remember to keep smiling regardless, because it drives everyone else crazy, if they weren't already.

[KBird01 in reply to FlipperTD]

🙃

[Rexz]

Hi Kbird01, What FlipperTD said, make sure you rehydrate yourself. Also, personally I stop all supplement, with the exception of B12 injections, two weeks prior to my blood tests. Only reason I don't stop B12 is that I just don't have that included in my tests any longer.

Also a tummy bug or any virus/bacterial infection will impact your ferritin reading as your body sequesters iron to fight these bugs. But you having autoimmune gastritis and therefore should have a complete iron panel not just Ferritin.

OK that's just my very humble opinion 😇

Best wishes Rexz

[KBird01 in reply to Rexz]

Thanks Rexz . Things have settled down anyway after a couple of days, but that leaves 5 days from having having been clear of symptoms to having the blood test. Will my ferritin levels still be raised to you think? This is one of the main things I'm wanting to check, as I've been low for a long time and have been supplementing.

I don't have a diagnosis of auto immune gastritis/B12 so like many people I've had to work my own way through this. Interesting about the gastrin test though, as I've always suspected there was an absorption issue going on. It's not in the blood test I've ordered, but I'll definitely check that out.

[Rexz]

Oh, yes, another test you might consider adding is serum Gastrin. As stomach acid decreases Gastrin levels increase. So if Gastrin is way above normal is indicative of low/no gastric acid.Rexz

[Rexz]

Hi Kbird01, I think you should be OK most test preps state to stop supplementing certain things (depending on test) 72 hours prior to the blood draw. If you suspect you may have PA/AMAG and if you do then Ferritin alone will not be a valid marker at any time. You should add a complete iron panel that includes:

Iron

TIBC - total iron binding capacity

UIBC - unsaturated binding capacity

Iron Saturation

Ferritin

But you should also add both PCAB and IFAB plus Gastrin.

These last are so important so we can get you diagnosed properly.

Btw - although a positive PCaB is not diagnostic of PA/AMAG by itself... A positive PCAB plus high levels of serum Gastrin is considered diagnostic.

The reason we need these is it not only affects your treatment but if you show positive you can push to have an endoscopic gastric mapping done.

Hope this helps.... Sorry if I've confused things. 🫣

Rexz

[KBird01 in reply to Rexz]

Thanks again Rexz . No you've not confused things at all. I have a full iron panel and bloods as part of the test. I had an IFAB which was negative, but had to to that privately after years of misdiagnosis and bad experiences with the NHS. I'm a vegetarian of 30+ years, so never really got t the bottom of what's going on, other than I tookmy health choices into my own hands earlier this year, started consistently supplementing and got my energy and life back within a couple of months. I'll read up a bit more about the gastrin stuff too, so thanks for the pointer. 😊

[Rexz]

OK consider adding Parietal Cell antibody and Gastrin.

I was negative for IFAB for three years before it showed up. The sensitivity of the IFAB test is purposely adjusted to be less sensitive to reduce false positives. But 90% of those with PA have PCaB. Although if positive its not diagnostic by itself if you add Gastrin it is if they are high

As disease progresses IFaB will increase over time and IFaB will eventually show up. Then as enough Parietal Cells are destroyed both IFaB and PCaB will diminish as your whacky immune system has neither PC or IF left to attack.

Good luck. Message me if you have questions.

Rexz

[KBird01 in reply to Rexz]

Thank you! 😊