Bloodwork / Supplementation question

[kicker2]

Ok, so I am still processing why I need to stop supplementation before having bloodwork. In my mind (and my Kaiser doc), wouldn't I want my bloodwork done when I am using my supplements? I would think my bloodwork would measure my the increased levels since I am constantly supplementing and then a doctor could say stop or lower my supplementation. If I pause my supplements and then have bloodwork done, my levels will have dropped and they won't reflect my level. What am I missing???

[PointOfReference]

To confirm for B12 - the test measures the levels of B12 in your bloodstream ONLY.

However, not all of the B12 is being used by your body at a cellular level. Therefore, the B12 test can give a false high reading if you have been supplementing.

In essence, taking supplements before a blood test will show that your blood is full of supplements.

But if you don't take the supplements for a period of time beforehand, the levels in your blood have time to reduce to a more accurate relfection of what your body is doing with the supplementation.

You want the test to reflect the true amount your body is using, not what is swimming around in your blood but may not actually be taken up by your body.

Hope that helps

[kicker2 in reply to PointOfReference]

Oh!!!!!!! The last paragraph of what you wrote esp pulled it together for me. Thank you for taking the time to help me get this thru my thick skull.

[Hidden in reply to PointOfReference]

Thanks from me too. I could never work that out either.

However I would be pleased if you could explain further, specifically in relation to iron.

My understanding is that you can't have too much free iron in the blood because it's toxic. It has to be bound to something.

In this case it's either transferrin or ferritin.

I can see that transferrin saturation may be raised whilst taking a supplement, because it's this that transports the iron around.

However, transferrin saturation should still be no higher than normal because this could lead to iron overload and may indicate haemochromatosis.

There might be a problem if transferrin is apparently normal, whilst taking a supplement, but "actually" is less than normal possibly indicating iron deficiency anaemia. However other tests would pick this up.

I'm not sure how Ferritin, being stored iron is artificially raised whilst taking a supplement and then falls back to a "normal" when the supplement is stopped.

Overall blood iron levels are quite well regulated by the hepcidin mechanism, so really, they shouldn't fluctuate that much.

I'm not suggesting that people shouldn't NOT stop oral iron before a blood test.

I'm still not sure why though. Have you any more idea?

[PointOfReference in reply to Hidden]

Please consult your gp re: iron. I am not an expert on this. I simply recommend suspending all multivitamins.

Iron is a different matter you should seek proper advice on

[Hidden in reply to PointOfReference]

Thanks.

[Hidden]

From what I can gather, I've not yet come up with a convincing reason why you should stop taking iron supplements prior to a blood test.

The most common advice seems to be 12 hour fasting before the tests. This is because the various levels can change (a little) during the day, depending on when you've eaten and even time of day.

E.g. blood sugar varies quite a lot depending on when you've eaten. The random cortisol test needs to be done specifically before 10 am.

How much this applies to iron is difficult to ascertain. Even if you eat, you're taking in iron.

Unless iron deficiency anaemia is suspected the key result for RLS is ferritin. Ferritin is unlikely to rise or fall significantly over a short period of time, that is unless there are other factors such as blood loss or inflammation.

I just read in fact, 70% of all iron is used for haemoglobin and that in a healthy male with no anaemia (low haemoglobin) you could go a year or more with no iron intake at all, before becoming anaemic. This would only happen when iron stores (ferritin) are depleted.

On the other hand, most iron you take orally is not absorbed anyway. I've read 98%. This is because it is blocked by hepcidin depending on serum levels.

Another point is that the effect of iron on ferritin levels and RLS isn't particularly fast. With oral iron, it can take months for it to raise ferritin sufficiently. If you stop taking it, it shouldn't fall that fast anyway, (unless there's anaemia or blood loss).

I've read members saying their RLS improves within days or a week of starting oral iron. Others have symptoms get worse within days or a week if they stop.

This seems highly unlikely!

Conclusion, if you're told you need to fast 12 hours before an iron blood test or stop taking iron for 2 days, 5 or a week then DO IT. I don't really think it'll make too much of a difference either way!

I hope that makes sense.

What applies to blood sugar, or B12 doesn't really apply to iron.

[WideBody in reply to Hidden]

The recommendation fro John Hopkins is to stop all iron supplements at least 48 hours prior to the test. But I promise you if you have been supplementing with iron it will skew the test Your Doctor needs to know you been supplementing. . I personally stop a week or more before the test. I do think my Transferrin Saturation Percentage is messed up because of supplementing (it’s 40%), my Doctor agrees.

Manerva is right again, as explained by my Doctor, my infusion could last one year, it could last 10 years.

[Hidden in reply to WideBody]

I'm not going to disagree with anybody that says either you have to stop or you don't have to stop. All I say is I can't see any significant reason for it either way.

If anybody's unduly worried about it I'd say if the doc, says do it, then do it, if they don't then don't. Personally I'd probably stop, just to be on the safe side. It won't do any harm to stop.

I'm not aware of any evidence on the subject. That doesn't mean there isn't any it just means I don't know any.

It seems logical that recent supplementation will skew transferrin saturation, but 40 or 45% isn't too high. I doubt if could be skewed above that unless you have something like haemochromatosis.

[WideBody in reply to Hidden]

From my favorite paper on the subject, section 9.1

reader.elsevier.com/reader/...

"The full iron panel is recommended at initial evaluation of an RLS patient and every time RLS symptoms worsen without explanation. A repeat iron panel is recommended about 3 months after starting oral iron and then based on rate of change over time every 3 to 6 months. As long as the patient remains on oral iron,they need to have their iron indices checked regularly. The patient should not take oral iron 2 days before the repeat iron panel is performed. Iron status after IV iron should be checked at 8 weeks after IV iron infusion and again 8 weeks later. The first 8-week,post-infusion iron assessment is to establish what level of iron stores were achieved with the infusion. The second post-infusion assessment is to see how stable the levels are. The risk of pe-ripheral iron overload is minimized by not giving iron treatment when transferrin saturation is>45%"

It also goes into detail why the test is to be performed fasted.

"Because (1) of the distinct circadian changes in serum iron(highest in the morning and lowest in the evening)[106],(2)of increases in serum iron immediately after food intake, and (3) of serum iron's importance as an independent determinant of iron status (plus part of the calculation of percent iron saturation),serum tests of iron should be obtained in the morning after an over night fast. Where possible, the last meal prior to the fasting period should have a limited amount of meat, particularly red meat. The full iron panel should include: serum ferritin, trans-ferrin saturation, iron, and total iron binding capacity. Soluble transferrin receptor should not be part of the routine iron panel as it is very expensive and has limited value in non-anemi cpopulation"

Manerva, I love your posts. I appreciate all you do. This is just a very sensitive topic for me. I really feel if I had addressed my iron deficiency and did NOT start DA drugs (10 years earlier) all this jerking would have been prevented.

[Hidden in reply to WideBody]

I appreciate what you're saying, I too think that when I was first prescribed a large dose of pramipexole without first considering iron therapy PLUS with no consideration of the fact I was taking an SSRI antidepressant and without any warning, ten years of my life could have been very different.

Thank you very much for the information about fasting, that dies make sense.

However, I'm still not clear why supplements have to be stopped, beyond the fasting period.

If you come across anything, can you let me know please.

[kicker2 in reply to WideBody]

Good info on the "full iron panel". I just messaged my dr asking if she had put the order in for the full panel. And good info on how often to have it taken after baseline. Thank you!

[kicker2 in reply to WideBody]

Thanks!

[kicker2 in reply to Hidden]

Yes, makes sense. Thank you.

[kicker2 in reply to kicker2]

Wow, I really got a conversation started on suspending iron supplementation before testing. Thank you everyone for taking the time to respond. I appreciate you all!

[SueJohnson]

I don't think you should stop taking what you are taking before the tests. I didn't, nor was it recommended that I do so by my doctor. Afterall you want to see the results in your tests of what you are taking. Update - Looking at this 2 years later I can't believe I said this. I was wrong. One should stop taking iron 48 hours before the test.

[kicker2 in reply to SueJohnson]

Meant to say in my earlier posts that when I asked my dr (GP) if I should suspend taking any of my supplements including iron, she seemed surprised by my question and quickly said no. I don't think this concern is common knowledge; and not likely to be asked often of doctors.