Where Are Our Ferritin Levels Supposed to Be?

I had always assumed I'd never had iron deficiency anemia. Actually, any sort of anemia. That my doctor must have tested that during my yearly physicals. Isn’t that a thing? Maybe it was a mistake to assume that.

During a recent emergency room visit, I had my ferritin tested due to blood loss from a horrific intestinal infection. At that time, my ferritin was 56. I thought, well, it wasn’t below 50, and I have always been under the impression that a level under 50 is when it is bad for restless legs syndrome (RLS).

However, when I looked it up in my online medical records, my previous ferritin number was at 46 — so, below 50 for no reason at all. Does this indicate that perhaps I should be on iron supplements for RLS? I began to question this.

What research says about ferritin levels and RLS

Certainly, before being put on medication for RLS, nothing was looked at. I was just immediately put on levodopa. This might have been an error or an assumption.

I was reading a research presentation found on the Restless Legs Syndrome Foundation’s site called "Iron Biology: What We Should Know When Managing Restless Legs Syndrome."

The presentation looks at all the research that has been done regarding iron and looks at the results. And, well, that is when we realize the answer is pretty complex.

It is stated in this presentation:

• RLS is associated with altered iron homeostasis involving brain, vasculature and lymphocytes
• There is a disconnect between serum-determined levels of iron and brain cellular iron levels in many RLS patients¹

What this means is we may have adequate levels of ferritin and iron in our blood, but low iron stores in our brain. It can be faulty to assume one number means everything is all good. All that research is what led to the new recommendations.

My doctor never suggested iron supplementation

Even if my doctor had been testing me, she would have been looking strictly at my blood levels of ferritin. It is clear that isn’t the whole picture.

I can say I only had my ferritin tested once before, and never specifically in the context of restless legs syndrome. But there were times I dipped below the 50 mark anyway. Yet iron supplementation was never even mentioned to me at all. I was immediately put on levodopa. I assume this is because I hovered around the 50 mark for ferritin and not consistently lower.

Updated recommendations for iron and restless legs

Iron supplementation is now recommended for all RLS patients with serum ferritin concentration of 75 μg/mL or less and transferrin saturation below 45 percent. This recommendation comes out of research showing that people with RLS "have lower than normal iron stores in some regions of the brain" but may not be anemic or show systemic iron deficiency. There is no commonly accepted method for testing iron stores in the brain, so a full iron assessment (including transferrin saturation) is important.²

When you look at the new recommendations, I definitely have to discuss with my doctor complete iron level blood work and iron supplement therapy. This could not only really help reduce my symptoms, but it could substantially reduce my need for my RLS medication.

Maybe this shouldn’t have been missed; but these are new recommendations, and I certainly didn’t present as anemic, so I can understand why it wasn't considered. No doctor knows every single thing about every single disease.

Were your iron levels tested? Do you fall under the new criteria for iron supplementation as well?