As promised to Seaside Susie, and 6 months later, please see below response I've had from Medichecks. I'm just sad it didn't come in time for Seaside Susie to see that they had eventually listened to us! It is an improvement on the previous reference range for over 60yrs females but it raises more questions in my mind so I will ask for a copy of the 'extensive study on ferritin' when it becomes available and hopefully it will clarify how these reference ranges have been arrived at.
'Thank you for your incredible patience while you have been awaiting the outcome of our ferritin reference range review. We conducted this with Inuvi lab, which has now changed the reference ranges to the following:
Females 18 ≤ age < 40 30 to 180
Females 40 ≤ age < 50 30 to 207
Females 50 ≤ age < 60 30 to 264
Females Age ≥ 60 30 to 332
Males 18 ≤ age < 40 30 to 442
Males Age ≥ 40 30 to 518
The lower limits of 30 are by the NICE threshold of <30 for iron deficiency. Our review of Medichecks data has determined the upper limits. This retrospective study used a large dataset of blood test results from 25,425 healthy participants aged 18 to 97 over seven years. This is the most extensive study on ferritin reference ranges, and we hope to achieve journal publication so that these ranges can be applied more widely.
I wanted to express my gratitude for your feedback in July 2023, which undoubtedly served as a motivating factor for this study'.
Apologies, I've not included a link to the original post, I can't see how to do it.
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Jazz80
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Please see below, original query to Medichecks, I didn't include it in the post avove as it's too long but it's just for context if anyone wishes to read:
Thanks very much for your prompt response, we seem to agree that the current INUVI reference range for ferritin is not compliant with guidance from the BMJ or the WHO, although it is compliant with the Nice Guidelines for the cutoff point at the lower end of the reference range.
It appears that the INUVI ferritin reference range is age related and at age 60, somehow, this extraordinary reference range kicks in. I cannot find any robust evidence to support this approach it is certainly not contained in any of the ‘gold standard’ evidence/guidelines i.e. NICE, WHO, BMJ etc.
Please see attached guidance from the Association of Clinical Biochemists (see attached) which I understand may be the evidence base which is used by INUVI to support the change in reference range for those over age 60 years. If this is indeed the evidence upon which this reference range is based, it raises several concerns in my mind:
1. This document is dated 2012 and I can find no evidence that it has been reviewed/revised more recently.
2. The status of this document is unclear with no indication of any qualifications/position held by the author.
3. It is stated; ‘Men and women, 60–90 years: 15–650 μg/L’,however, there appears to be no supporting evidence for this other than a vague preamble i.e.: ’The normal reference interval has a wide range because of age and gender variations. Intra-individual variation of serum [ferritin] is very low and no circadian variation has been determined’.
4. It also states; ‘The reference interval also has considerable variation depending on method used and therefore should be individually determined for each laboratory’. This statement appears to be a ‘catch all’. The method used by INUVI appears to be-able to accommodate the NICE Guidelines etc. satisfactorily up to the age of 60 years so it cannot be ‘the method’ which is dictating the extraordinary change in the reference range at age 60 years.
5. The references at the end of the documents provide no evidence to support the changing the reference range at age 60 years, indeed the references seem to be a bit of a muddle and of varying relevance. Most of the links, to the references appear to have expired or the documents are unavailable.
6. As you say the NICE Guidelines provide no clear upper limit for the ferritin reference range, however the BMJ recommends 300 as an upper limit for post-menopausal women and men, and 200 for pre-menopausal women and the World Health Organization ‘Guideline on Use of Ferritin Concentrations to Assess Iron Status in Individuals and Populations (2020)’ (see attached) identifies the cut off for apparently healthy individuals ‘Older persons (60+ years) 150 females and 200 males’ and 500 for non-healthy individuals’.
I note that Medichecksinterpret ferritin levels based on NICE and BMJ Guidelines, therefore I don’t understand why you are showing my results on a reference range of 30 – 650? Your website states, ‘we show all results within the normal, borderline, and out-of-range scale so you’ll be able to see where you sit for each biomarker and what this may mean for you’, this is great and very helpful. However, in this instance it’s misleading, resulting in people over 60 years of age with ferritin levels that were nudging the middle of the range with the previous laboratory now finding themselves plummeting to the very bottom of the INUVI range, it is quite shocking! Conversely over 60’s with levels of 300 – 400 (the upper cut off limit of the previous range) will be looking at results around mid-range with INUVI. Worst of all are those people whose ferritin levels are approaching 600 or so, they will consider themselves still within normal (INUVI) range when the evidence suggests they are not and may even be seriously ill.
Please correct me if there are any inaccuracies or omissions, I’m in no way an expert on any of this and these are just my own thoughts, but common sense alone tells me there is something very wrong here. There may be other laboratories who use this approach, but I have been unable to find any, I do hope you will look into this because as it stands at the moment it seems to me that people over the age of 60 are at risk of being misled in respect of what are ‘normal’ and what are out-of-range ferritin results and rendering them unable to understand what the results mean for them.
Apologies this is so long but I suppose I’m hoping that you can either provide me with hard evidence are to why INUVU is such an outlier, and they are correct in their approach or what measures are going to be taken to bring them in line with the Guidelines/evidence identified above.
Just want to emphasise, that the NICE threshold of 30 needs to be interpreted as:
If ferritin is below 30 it means iron deficiency and further action is required.
But being over 30 doesn't mean that the person does NOT have iron deficiency.
(Adding that because ferritin tends to rise when there is inflammation, it could be inflammation that is taking the ferritin level from below 30 to above 30.)
Jazz80 This is amazing! I am at a loss for words! What a smart and savvy approach, and to actually make a difference with such an opaque and inflexible system (not to mention the many egos to navigate.)
As I’m dealing with low ferritin too, even more personally valuable.
I’m very grateful for the time and effort you put in to follow up on this and provide us all with this info.
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