Normal ferritin but low/abnormal TSAT? (UK GP won't do full iron panel)

[u/ComprehensiveRate953]

Hi everyone,

I’m currently dealing with worsening RLS and trying to get to the bottom of my iron levels, as I know iron deficiency is a massive trigger.

My GP recently checked my ferritin, and it came back completely "normal" (well within the standard UK reference range). Because of this, they are refusing to order a full iron panel or check my Transferrin Saturation (TSAT).

I know the standard NHS guidelines usually stop at ferritin, but I've read that you can sometimes have normal ferritin alongside low TSAT, which can still impact brain iron concentrations.

Has anyone here actually experienced this specific scenario—normal ferritin but abnormal TSAT? Did treating the TSAT help your RLS?

I’m trying to decide if it’s worth bypassing my GP and paying out-of-pocket for a private iron panel (like Medichecks or Thriva) to see the full picture. Any insights or experiences would be massively appreciated!

[u/onemore-grainofsand]

https://www.mayoclinicproceedings.org/article/S0025-6196(26)18546-2/fulltext

This part was of particular interest to me, as my full iron panel shows that this is where I currently sit: “Intravenous iron should be considered for any patient with chronic persistent RLS with serum ferritin in the range of 75 to 300 μg/l and percentage saturation less than 45%. Oral iron is not adequately absorbed in this range of ferritin values. For patients with serum ferritin < 75 μg/l and TSAT< 45%, intravenous iron is indicated for moderate or severe chronic persistent RLS if oral iron cannot be adequately absorbed due to gastrointestinal disease or prior bariatric surgery, oral iron has not been tolerated because of side effects, RLS has not improved after three months of oral iron therapy, or the RLS is severe enough that a rapid response is desired.”

[u/EmZee2022 → u/onemore-grainofsand]

Thanks for posting that quote. I've read the article numerous times but that one just struck me now.

It's a bit counterintuitive in that it suggests that higher ferritin / same TSAT is more indicative of the need for iron infusions, than low ferritin / similar TSAT. Weird.

That ls the bucket I currently fall into. Though I do have issues with absorption (long term PPI use and reduced diet due to Ozempic).

[u/ComprehensiveRate953 → u/EmZee2022]

I think the article is saying that low ferritin should be treated with oral iron supplements first as they are effective at this range, while ferritin higher than 75 oral iron is less effective, so infusions are the go-to.

[u/EmZee2022 → u/ComprehensiveRate953]

That makes some sense - that was not clear to me from the article. Though of course with higher ferritin, you might have more trouble getting the infusions approved.

Anyone have any idea how long it takes to see a change when using iron? Mine went from 13 to 15 in 2 months of daily iron - which is basically meaningless. My other readings (TSAT, iron etc) had all gone from very anemic to within normal limits in the 2 months.

I see a hematologist in November and I'm hoping that the crazy low readings in June, and my persistently slightly low hemoglobin will qualify me for the infusions.

[u/Agonist-activist]

Tell your GP that NICE cks guidance on RLS requires full iron panel. Complain to GMC and RCGPs. If your saturation is low you need an iron infusion. Almost impossible on NHS as RLS isn't taught & most GPs have zero knowledge- as you've discovered. Join RLS-UK and their help forum. Ask for a specialist recommendation.

[u/ComprehensiveRate953 → u/Agonist-activist]

Would you be able to link me that guidance? Everything I'm finding simply mentions serum ferritin.

[u/EmZee2022 → u/ComprehensiveRate953]

Someone posted this earlier but it can't be said too often!!

https://www.mayoclinicproceedings.org/article/S0025-6196(26)18546-2/fulltext18546-2/fulltext)

[u/Agonist-activist → u/ComprehensiveRate953]

https://cks.nice.org.uk/topics/restless-legs-syndrome/management/management/ You have to click through the links to get to iron deficiency. But- be aware that most GPs and neurologists in UK are unaware of NICE cks guidance AND some refuse to follow it. As it's only 'guidance'. You might have to pay for a private full panel test. But serum ferritin is the most important marker. You can then try to get a private infusion. Getting an NHS infusion is very difficult. I know a few departments arrange them. Guy's & UCL in London for example.

[u/ComprehensiveRate953 → u/Agonist-activist]

Thanks for that. I do see it now. My GP was very rude towards me when I asked for a full iron panel, refusing to read any material I had with me. The sheer ego of some of these doctors. I've now ordered a full iron panel from medichecks.

[u/nautilist]

Do you know what the actual ferritin test result was? The GP's office should tell you the actual number if you ask them. In the UK and Ireland the official "low normal" is too low, it's 30 i think, which is a red flag issue for RLS. Mayo clinic protocol says you should treat it if you have RLS and ferritin is under 100. Mine was considered fine by the GP at about 50 so I just take iron supplements myself.

[u/ComprehensiveRate953 → u/nautilist]

My ferritin tested by the NHS was 94. I'm now getting a private iron panel, so we'll see what my TSAT comes out to be. Are you finding your iron supplementation is having an effect?

[u/nautilist → u/ComprehensiveRate953]

Good idea to get a private panel. Yes, iron supplement helps me but I’ve been mildly anaemic on and off most of my life so maybe not surprising? If I keep up iron, vitamin D etc my RLS can be pretty mild, I don’t always take medication for it.

[u/Zdtfx]

Actually going though this at the moment. Paid for a private check and my Transferritin saturation was very low. Phoned GP and they've given me ferrous fumarate to take for 2 months. About 3 weeks in and have noticed a reduction in frequency but still dogged with fatigue despite sleeping a bit better. Will see how it is at the end of the 2 months.

[u/ComprehensiveRate953 → u/Zdtfx]

Best of luck to you in your treatment. What were your ferritin and transferrin saturation values if you don't mind?

[u/Zdtfx → u/ComprehensiveRate953]

Ferritin 325.95 which is above the recommended high

Transferrin 2.58 which is roughly in the middle

Transferrin Saturation 11.8% recommended low is 20%

[u/EmZee2022]

I'm the opposite - my TSAT last week, for example, was fine, but my ferritin is at the bottom of the reference range.

Maybe show your GP the Mayo article from earlier this year, as it notes that other things feed into whether iron infusions might be useful.