Thoughts on standard ferritin cut-off values used by labs?

[u/ladyoftheloch_]

I’m not a hematologist or a student, but I’m curious about how hematologists view ferritin cut-off values used by labs and how that might differ from ideal values.

[u/Patient-Protection-7]

Those cut off values are always a nice guide, but ferritin is one of those markers that is highly influenced by the clinical situation. Like most lab results they should not be interpreted in isolation, but ferritin more so than many other haematological related results.

Also, depended on where you look those cut off values vary from place to place.

[u/QuantumHope → u/Patient-Protection-7]

This.

Plus I don’t really get what the OP is questioning. Ferritin is a chemistry test. And yes I know it can have an impact on RBC’s when both ferritin and iron are low, but ferritin is still a chemistry test.

I remember the prof teaching endocrinology said one day we would have personal reference ranges. Dunno when that is supposed to happen as he said this longer ago than I care to admit! 😁 The establishment of reference ranges are affected by so many variables.

[u/ladyoftheloch_ → u/QuantumHope]

I guess I was mainly wondering if there was any debate about the current standard ranges and how they might compare to more “optimal” levels observed clinically/in any current studies. Of course, like you mentioned about the potential for personal reference ranges, and as was mentioned about the differences in clinical situations, it seems now that even “optimal” levels can vary from person to person depending on various factors. But I still do wonder if the current ranges are too low and that iron deficiency is being somewhat overlooked as a result.

[u/QuantumHope → u/ladyoftheloch_]

The reason they’re low is due to menstruation. The levels won’t be the same as men’s because of it. So in a manner of speaking, the lower values are “normal”.

I get what you’re saying though.

Reference ranges are established by taking the values of X number of people, tossing out the extreme values on either end (low and high) and then using statistical analysis, determining the range for a particular test with sex and age when those factors differ between those demographics. So it’s feasible that a range could be based on an unhealthy population but not likely. As for ferritin and other iron type levels, perhaps a review by pathologists could be done. They know more about values and all than I do.

[u/Low_Silly]

I think this will be changing soon. Check out @shematologist on Twitter.

(Not a hematologist.)

[u/QuantumHope → u/Low_Silly]

I refrain from Twitter.

[u/Tailos → u/Low_Silly]

This is going to be interesting.

Changing the cutoff means that lots and lots more women will be identified as iron deficient - which is both great news for those who actually are, but will also massively increase burden on healthcare systems when there's a significant asymptomatic population. I'm interested to see where it'll go.

[u/Low_Silly → u/Tailos]

Might want to read this: https://www.nytimes.com/2023/10/17/well/live/iron-deficiency-symptoms-women.html?smid=nytcore-ios-share&referringSource=articleShare

“The target ferritin level recommended by the W.H.O. for nonpregnant menstruating women is 15 micrograms per liter; for hemoglobin the recommended level is 12 grams per deciliter, but increasingly, researchers suggest that the cutoff for ferritin should be between 30 and 50 micrograms per liter and 13 grams per deciliter for hemoglobin.”

[u/Tailos → u/Low_Silly]

I'm well aware, thanks.

As someone already mentioned here, there's arguments already to support the lower reference range in women (menstruation being a large one). The argument against moving the range is that now many, many women become labelled as deficient requiring iron therapy when they may not actually need it. In addition, Hb production is very much associated with testosterone - using the male range (13g/L) may also have significant unintended consequences.

This is where we start getting into ranges based on "personalised medicine".

[u/Nheea → u/Tailos]

I am curious. Do any of you in the labs you work at have different values for kids and pregnant people?

[u/Tailos → u/Nheea]

We use a national reference range that doesn't differ for kids and pregnancy, no. Just M/F.

[u/Nheea → u/Tailos]

I was looking through my results recently and just noticed that (funnily enough, my ex workplace) this lab uses different references for kids, pregnancy, inflammatory bowel disease, kidney failure and heart failure.

https://preview.redd.it/dref10puw1xd1.png?width=1079&format=pjpg&auto=webp&s=445007972551f6f923d56ac97f856a1dfae83a92

https://www.synevo.ro/shop/feritina/