Hello and welcome to BJGP Interviews.

I'm Nada Khan and I'm one of the Associate Editors of the bjgp.

Thanks for taking the time today to listen to this podcast.

Today we're speaking to Dr.

Rob Perry, who is a gastroenterology Clinical Research Fellow based at Imperial College London.

We're here to talk about the paper he's recently published here in the BJGP titled Evaluating the Role of Fecal Calprotectin in Older Adults.

So thanks, Rob, for joining me here to talk about your work.

And I guess I just really want to preface this by saying that a lot has changed in the last few years just in terms of testing for inflammatory bowel disease and bowel cancer in general practice.

But I wonder if you could just talk us through this, some of the different guidelines and why you wanted to do this study.

Oh, yes, thank you for having me.

Firstly, and the rationale for the study is that, you know, consultations for gastrointestinal symptoms make up a large number of consultations in primary care.

I think the figures around 10%.

And whilst fecal cow protection is an increasingly well established test for differentiating between inflammatory bowel disease and functional or other gastrointestinal or non inflammatory gastrointestinal diseases, its role in older adults is far less well established.

With varying guidelines for clinicians in primary care, the NICE guidelines make no specific mention, for example, of age, other than that calprotectin should not be used where age is considered a risk factor in the context of certain symptoms.

For suspicion of cancer, the BSG guidelines on IBD use a cutoff of 40, above which they suggest calprotectin is not used.

The something called the NICE York Fecal cow protectant care pathway suggests an age cut above 60, which is a NICE endorsed pathway.

So there's some uncertainty there in the literature about which cutoff should be used for fecal cow protectin.

And the reason any cutoff is suggested is because data has previously shown that calprotectin lacks sensitivity for diagnosing colorectal cancer.

And as age is considered a risk factor for colorectal cancer, guidelines normally mandate earlier endoscopic evaluation of patients with GI symptoms in older age groups.

And can you just talk us through briefly what you did here?

So you looked at patients referred for a colonoscopy at one single centre, so at Imperial College Healthcare Trust.

But just talk us through briefly who was included in the study and what were you looking at specifically?

So looking at patients where calprotectin was being used for diagnostic purposes, so calprotectin is also, as you probably know, well established for monitoring patients with existing ibd, monitoring response to treatment for flares, et cetera.

We were just looking at patients where it was being used for diagnostic purposes.

So any patients with existing IBD were excluded from the study.

And then, yes, as you said, anyone who had a calprotectin within a six month period back in 2021, who then subsequently within a one year period had a colonoscopy performed at Imperial, which is the local referral centre, that were included in the study.

And we only looked at adult patients.

We had a cohort of older adults which we used to cut 50 and above, and a younger cohort below that.

We didn't look at pediatric cases, that was how we selected patients.

And then we reviewed available electronic documentation to ascertain the diagnosis of the patient, looking at clinic betters etc, as well as looking at other tests that patients may have had performed when their symptoms are being evaluated.

Fit testing, for example.

We also looked at CRP and haemoglobin.

By collecting that data, we were able to ascertain the diagnostic performance of chiroprotectin in the two respective cohorts.

And also in comparison with some of the other clinical tests that I mentioned.

Yeah.

And as you point out, because these tests might be used in quite a varied fashion depending on patient age or presentation, I suppose it's important to kind of work out what the diagnostic capabilities of them are.

And I think that's what this study really aimed to achieve.

Really.

Yes, exactly.

So we were trying to look at how calprotectin performed in the older age group compared to the younger age group, and also looking at how its performance relative to fit testing in those two cohorts.

We looked at the performance of calprotectin, the differentiating between inflammatory bowel disease and non organic GI pathology.

And we also looked at its ability to differentiate between organic GI pathology more generally.

So inflammatory bowel disease, colorectal cancer and other significant GI diagnoses and non organic pathology.

Those two questions, which I think are important questions when considering patients presenting with GI symptoms in primary care.

And just talk us through what you found here.

And I think the results were really striking in terms of things were different according to age and maybe not surprisingly.

But talk us through that.

I think the key findings are firstly that calprotectin remains a sensitive test in both groups.

So sensitivity when using a cutoff of 50 micrograms per gram, which is the nice advised cutoff for considering a positive calprotectin Test suggested by nice.

There are other, you know, there is other data in the literature about altering the cutoff which calprotectin is considered positive, but 50 is the cut, you know, is one of the cut offs we looked at and is what is suggested by, in the NICE guidelines using that cutoff, you get sensitivities of over 90% for diagnosing IBD from non organic GI pathology in both age groups.

What you see in the older age group is a significantly lower positive predictive value.

So positive predictive value of only about 12%.

And using that cutoff in the patients who had, again using that cutoff of 50 in the small number of patients who did have colorectal cancer, if you then did try to push up the threshold at which calprotectin is considered positive, as many guidelines do suggest, you would then start to, to miss cases of colorectal cancer, which just highlights one of the important messages of the paper and that is clearly documented in the NICE guidelines that calprotectin shouldn't be used as a biomarker for cancer and if cancer is suspected, patients should be referred on the appropriate urgently suspected cancer pathway.

We also found that calprotectin did perform better than fit tests for diagnosing ibd.

But, but there's also potentially some future work to be done in patients who may have had FIT testing because of concern over potential colorectal cancer.

But in patients where FIT is negative, calprotectin may then have a role as a good rule out test in that group where you've already ruled out suspected cancer.

So that's maybe an area for future work and maybe it just helps to allow us to think about how we may have a more kind of joined up pathway for evaluating patients with lower GI symptoms in primary care.

And I know some local guidelines might suggest faecal calprotectin alongside FIT in younger age groups.

What are your thoughts about this based on the results of this work?

I think it depends what symptoms the patient's presenting with.

I think if patients present with symptoms that according to the NICE guideline that's potentially suggestive of colorectal cancer, then obviously they should be evaluated, you know, appropriately with FIT testing or, you know, onward referral.

And I think, you know, I think calprotectin clearly has a role in younger patients for differentiating between non organic GI diseases and ibd.

I think in older patients it's, you know, clearly for a much, if a tool is for a much narrower group and you know, shouldn't be used where cancer is suspected, which for A large number of patients presenting with GI symptoms.

In this group it will be.

Although there may be this subgroup of older patients where because calprotectin maintains a high sensitivity, it does still have a role potentially that fit negative group that we were talking about.

Though I think further research is needed to find exactly what that group is.

And I think just generally from my discussions with other GPs there is sometimes a bit of uncertainty about which tests should be used in patients presenting with lower GI symptoms.

And I wonder what you want to tell GPs based on the results of this study and your background about the use of faecal calprotectin in fit.

Yes, I think that the study highlights and what is already in the guidelines that calprotectin shouldn't be used if colorectal cancer is suspected.

So that's the first thing to say.

I think there is a role for calprotectin clearly in patients under the age of 50, younger adults representing the GI symptoms without, you know, without, without obviously alarm symptoms.

But I think you should calculating should be used cautiously in the over 50s.

Whilst it remains a, you know, a sensitive test, it clearly lacks in specificity the poor positive predictor value.

And as we said, it is not a test for cancer which is most or a large, a large proportion of patients in that age group who have lower GI symptoms will meet criteria for referral on a cancer pathway.

I think that's the key message for the study really.

So stay aligned to the current two week wait guidelines clearly.

But just think carefully about calprotectin testing in those older patients.

I think the study confirms it's a sensitive test, but that again should not be used as a test for colorectal cancer.

And so maybe in a proportion of patients where who don't make referral for referral on a cancer pathway, it may have a role due to its high sensitivity.

But with those caveats, fair enough.

Okay.

Any other main findings you want to highlight from this paper?

So I think, yeah, I think those, the points we've discussed are the main points.

I think it is interesting to note that for the diagnosis of ibd, calprotectin did outperform FIT testing, which I think suggests there is still a role for calprotectin in the diagnosis of ibd.

Some studies suggested that FIT tests may well be positive in the context of ibd, particularly where there's obviously bleeding present, which often may be with more severe inflammation.

I think it highlights that somewhere in the pathway for evaluating patients in primary care with GI symptoms, particularly in younger patients, there is likely still to be a role for calprotectin.

So I think that's an interesting additional finding.

Confirms, you know, confirms what most GPs are already doing.

I think beyond that, I think that the key points, as we said, are whilst calprotectin maintains its sensitivity in older adults, caution should be used on exactly which patients it's used in, in that group.

And as you said, it's important to look at the wider clinical picture and there will be a cohort of patients with potentially a strong family history or symptoms strongly suggestive of inflammatory bowel disease, where you might want to think carefully about what you're testing.

I think you also, I mean, you do also have to ask with those patients whether actually ultimately those patients need referral for endoscopy, irrespective of what their calprotectin shows.

You know, even if cancer is not suspected, if there's a very high suspicion of IBD and, you know, you still might consider onward referral even in the context of a negative calprotectin, if you have a very high index of suspicion, they may be patients where is still appropriate, maybe through advice and guidance or discussions with colleagues.

You may not want just to draw the line at a negative calprotectin.

But yes, those are the kind of patients where you aren't being referred on a cancer pathway, where a calprotectin is of potential benefit.

But like any test, it's important to interpret it in the clinical context.

And if it's not, if there are other things you're concerned about, you know, it's only one test and needs to be interpreted in the context of the patient's symptoms and their individual risk factors.

I think this is really interesting work.

Again, looking at that sort of primary secondary care interface and how tests are being conducted, how referral pathways are being designed or co designed.

From your perspective as a secondary care colleague, where do you think the next steps are from this work and where do you want to see this research going next?

We always say that we want more data and want to be able to look at things in more depth.

I think that's true, particularly for trying to work out where calprotectin and fit testing fit in more widely.

With patients presenting with GI symptoms across all age ranges, I think it can be difficult for gps to know exactly which set of guidelines they're going to.

I think trying to join all these things up to work out exactly which pathway which patient should be on is important.

That's why I mentioned that in older adults there may be potentially a role for calprotect in the context of a negative fit.

So in that lower risk subgroup of older adults and I think some more work looking at that would be interesting and I think also for adults more generally, including younger adults with need to work out how to use calprotectin in the most effective way possible, are there certain symptom groups that should be targeted with calprotectin?

Some of the data out there suggests that, as we talked about earlier, that calprotectin can often result in a low diagnostic yield of subsequent investigations, that is lots of false positives.

And I think trying to make sure we're using calprotectin as effectively as possible and not exposing patients to unnecessary investigation is also important.

And I think more looking into that would be interesting.

Great.

Some great pointers for future research, but I think that's probably a great place to wrap things up.

So I just wanted to say thanks very much for joining me.

Thank you very much.

And thank you all very much for your time here and for listening to this BJGP podcast.

Rob's original research article can be found on bjgp.org and the show notes and podcast audio can be found@bjgplife.com and that's the last podcast for this season of BJGP Podcast.

We'll be back again towards the end of January 2026 for more interviews showcasing current research and clinical practice articles from the Journal.

Thanks again for your time and by.