I have been having a few tests to try and understand the different results I get for Ferritin tests with Medichecks compared to the NHS.
The last comparison was to test ferritin on 16th Dec, all using venous draw, by same nurse at same time and send 3 samples off to 3 labs - 1 x NHS, 1 TDL (medichecks) and 1 County.
To me County's results are a bit all over the shop. TDL is still a % variance from the NHS results but seem to be more consistent with the absolute result from the NHS but also the % increase over the time period. One reason that was suggested was that the County sample took longer to reach them, and be tested, and that could explain the higher concentration in the blood.
Medichecks seem okay with the variance but I am not really satisfied. For me as a patient and customer I interpret the results quite differently between being 29% through a range, and being 4% through a range.
Interested to hear anyone else's thoughts on this?
Interesting! Not according to my blood results but it could be an oversight I suppose. Would certainly help me to get comfortable with understanding these results.
I agree it seems odd... do you happen to know how long it took for your labs to be tested by county?
The two I had most recently were venous draws so were quite a big tube full. Which I suspect would mean they were less impacted by the delay. These results were lower and nearer to my NHS results. It would be interesting and concerning to know whether the small finger prick vials are more susceptible to deterioration and therefore return higher ferritin concentration. My own finger prick samples were higher.
I sent them both back using Royal Mail's Special Delivery Guaranteed by 1pm Next Day, tracked and saw they were signed for around 8-9am at the lab the next day, so no delay in delivery - just 24 hours after taking the sample.
My ferritin has dropped since then and I am working on trying to raise it (eating liver every week, I got lazy about cooking it which is why my level dropped). Was about 57 a couple of months ago, have an iron panel here to do end of January or maybe February. No chance of getting another NHS test I'm afraid.
The results may vary slightly among laboratories, but in general, normal ferritin levels range from 12 to 300 nanograms per milliliter of blood (ng/mL) for males and 12 to 150 ng/mL for females.
Yeah i guess that's an article that has cited that but on my blood results it says:
Serum ferritin level 27 ng/mL [15.0 - 300.0]
Ferritin >15 and <100ng/mL. With low Hb and MCV,
a normal ferritin in the presence of inflammatory
changes does not exclude iron deficiency.
And according to the doctor at medichecks labs set their own ranges according to the population they serve. So for some reason according to the calibration of the two labs under medichecks their ranges are different.
However, even the ferritin level can be normal, around 50-100, and the patient may still actually be iron deficient. This makes the diagnosis somewhat tricky in certain cases.
yes I've done full iron panels, that's how this came about because I had to go to Medichecks to get the full iron panel, and then i wasnt sure whether to trust it because the ferritin level was so different haha!
Also with ferritin (like vitamin D) it’s the actual result that’s important not the % through range
Though that still doesn’t explain why NHS result is 27 and the other 2 are much higher at 44 and 57
I would suspect that you’re right and time delay between blood draw and test may affect results.....in which case postal kit ferritin testing is extremely unreliable and not worth doing
Would be interesting to here what labs say to explain the difference between the three test results
He said the difference is partially the postal time for the county result and partly they accept a variance / fluctuation - and 14% is normal i think he quoted. He wondered if NHS was slightly low in that acceptable fluctuation, County is slightly high and maybe TDL is about right.
Next steps because I wasnt entirely satisfied by this result - because I really do think County's is the one that looks wonky as it jumps around ( whereas at least TDL increases in a similar amount to the NHS increases) - is to get a second opinion from someone at Notts Uni Hospital, a clinical biochemist. He's also going to get the latest external quality assurance data for me which he said might help to allay my concerns.
That is interesting about the range point - I just thought it was odd they were using a range so vastly different but potentially it's just that the NHS doesn't serve you up a sex specific range?? no idea tbh.
Also with ferritin (like vitamin D) it’s the actual result that’s important not the % through range
I'm not convinced about that, to be honest.
As an example from my own records...
Several years ago I had three tests for ferritin a few months apart. I was supplementing with ferrous fumarate 210mg, with a dose of one tablet, three times a day all the way through the time that these three tests were done. I always stopped taking iron for a week before testing, and I always followed the same instructions for iron testing as I do for thyroid testing in relation to fasting and time of day. All results are in mcg/L.
Result 1 : 21 ... followed six months later by ...
Result 2 : 67.7... followed six months later by ...
Result 3 : 51
If the actual numbers are what is really important then it suggests a big improvement between results 1 and 2, and then things got worse again between results 2 and 3. But I was taking three iron supplements a day of the exact same type and at the exact same dose all the way through. There was no reason for my third results to have got worse.
If I actually post the percentage through the range the results give a different picture :
Result 1 : 6% of the way through the range
Result 2 : 14% of the way through the range
Result 3 : 28% of the way through the range
When looked at as a percentage through the range my results were clearly improving all the time and in the circumstances the results make sense.
Don’t blue horizon go to county sometimes? Can you see which lab it went to? I wonder if more likely you got an over inflated county result, in line with my results and the ones @seasidesusie has received.
The BH results are from about 7 years ago. BH has a contract/business relationship with Spire Hospitals. This is the relevant website - they are still in business together :
I pay BH but go to a local Spire Hospital to get the phlebotomy done. The phlebotomy is all included in the price. Spire sends the blood to one of their own labs.
The particular BH test result I quoted was provided by "Blood Sciences Gatwick Park" according to the printout I received, which comes up with this link when I google it :
I really do not have any explanations. Seems unlikely that your iron levels could change at the rate implied by the ferritin results.
Which allows a possibility of the ferritin changing for other reasons such as inflammation. Or the lab results not reflecting ferritin levels in the same way.
I suggest that you write to each lab, listing your results, and asking them whether they have any explanation of the results.
However, is there any possibility you didn't fast for 12 hours before some of the blood draws? Or that you were dehydrated (to some extent) when some blood draws were done?
Well all of this is being done through communication with a doctor at medichecks so he is offering an explanation of sorts and I am questioning it which is why he is also going to ask this biochemist from notts uni for his opinion. I can ask him for the labs own views on it but he assured me they all pass their assessments etc.
His main reason for the difference is that the nhs and these other labs use different platform analysers.
Next reason is they accept some variation as normal.
Range is set by lab depending on population they serve.
I always fast and always do draw at same time c. 7am and always drink a lot of water so I really don’t think so. I also give up supplementing iron and biotin containing supplements for a week before. It’s quite peculiar and it doesn’t seem as though it’s just me that has experienced this phenomenon
Range is set by lab due to the population they serve
The lab in Guilford has changed their female haemoglobin range since 2017. Considering their population overlaps with the one served by TDL who always had the range they now use I find that suspect.
They were all exact same time by same nurse she kindly agreed to fill the medichecks tubes for me at same time as NHS. Would you expect ferritin to fluctuate over the day normally?
That was the idea behind that last three tests. To see what variations would come out when they were all on same day at same time as medichecks were using that to explain the previous variations.
Well he’s already explained it in his mind. Mainly the platform analysers are different. And they do expect a variation and this is within normal variation. Will be interesting to see if the guy from notts uni hospital agrees.
Whilst ferritin measurement appears to have its uses, if variations due to the known effects of inflammation and other issues are overlaid on what you are seeing, we might as well roll dice.
That is exactly how I feel about it. I explained to the medichecks doctor that how am I supposed to rely on this as a customer when their results would indicate I probably don’t need to supplement but the NHS result would suggest that I do.
I’ll see what he comes back with and then explain that I feel I need to raise it with UKAS. He mentioned they have UKAS inspections and nothing is currently being raised as an issue and he also said he’d share the latest external quality assurance results with me. I don’t like to cause them problems but I’m not entirely convinced by their explanation that it’s not a problem.
As someone said, if degradation occurs in transit to the extent that it can turn a result from low level to okay then its not really worth offering it as a test.
Not quite as bad as the theranos scandal, but it’s not exactly reassuring
Thing is, you are not alleging they or anyone else is actually doing anything wrong. Just that results across labs are inconsistent. Which, until explained, could have a variety of causes.
Once the causes are understood, action might be required.
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haha - do you subsist entirely off chicken livers and clams?
Update - different results via Private and NHS
Medichecks Ferritin same sample, two different results
🌈 Latest Medichecks Results 🌈
Significant Difference between Medichecks and NHS Blood Test
