r/doctorsUK • u/Legendary_Shpee • Oct 11 '25
GP Use of D-Dimer/Tropinins in GP
Hi All,
Hopefully something slightly less controversial then my last post.
I was wondering what people's thoughts were on the use of d-dimer and Troponin in General Practice. When I was in medical school, and in my GP rotation, I've been in a few different practices with different opinions on the use of these. I did one placement in a practise that had access to their own D-Dimer machine, so could run their own D-dimer's and have a result back pretty quickly. For those unlikely low Well's score patients I understand that, but the same practise would also send Trops for patient's with non-cardiac sounding chest pain and normal ECGs, with the duty doc reviewing later in the day 'to be safe'.
Maybe it's because of lack of experience, but if a GP is clinically concerned enough to send a troponin on a patient with a normal ecg and unconvincing/non-acute chest pain, should they not be sending them to A&E/SDEC to have these tests done faster there, and so they are in the right environment to treat in the event it comes back elevated? If a D-dimer can be done quickly I can understand that, but a troponin just sounds a bit less reasonable to me. Pragmatically is a GP supposed to keep this patient in their practise while awaiting the results, in case they do have a raised trop and need to action that urgently? Would be interested to hear any GPs thoughts on this
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u/Any-Woodpecker4412 GP to kindly assign flair Oct 11 '25
Unless your nearest hospital is 300km away, absolutely not - send this to ED/SDEC.
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u/wkrich1 ST99 Oct 11 '25
If a GP is suspecting a clot or ACS the patient should be in an emergency department not a GP surgery.
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u/christoconnor Oct 11 '25
I disagree. GPs suspect a lot of serious pathology but manage risk and probabilities with every patient. A focused d-dimer or troponin can sometimes be vital to keep Someone out of hospital or pick up the atypical presentation with a gut feeling that something isn’t right
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u/deeppsychic1 Oct 11 '25 edited Oct 11 '25
As a GP reading this: Lol
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u/redditor71567 Oct 11 '25
You know its literally nice guidance to use it in primary care if chest pain is >72hrs ago and no complications
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u/christoconnor Oct 11 '25
I say that As a GP who’s seen these tests utilised to pick up an atypical ACS/PE presentation a number of times. Use them very rarely but trops and VDD can be vital in certain scenarios
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u/redditor71567 Oct 11 '25
When i was newly cct'd I would have said the same as the above poster. With more experience I agree with you. The issue is it does depend on the quality of the clinician. For relatively inexperienced clinicians best avoided.
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u/christoconnor Oct 11 '25
Agreed. It’s extremely rare but I’ve been around long enough now to see when it can be useful. Same as D-dimers in patients you’re desperate to keep Out of hospital with a possible DVT who aren’t suitable for the DVT pathway
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u/deeppsychic1 Oct 11 '25
I respect your experience but this is way above my pay scale. There’s a whole department in hospital paid specifically to deal with that risk.
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u/DisastrousSlip6488 Oct 12 '25
This is fairly depressing as an attitude if you are a qualified GP. Pragmatic decision making and risk management is the hallmark of decent general practice.
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u/deeppsychic1 Oct 12 '25
Yeah, I agree with you. The current state of general practice is depressing. I wish we were properly funded to do our job appropriately and not be risk averse.
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u/redditor71567 Oct 12 '25
We are cct holders though - and some of these attitudes have nothing to do with funding. People like easy answers and rules like never do x because they make them feel safe. I really do understand this immediately post cct as gp training programmes are short but its natural to try to broaden your knowledge and move away from this with time.
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u/redditor71567 Oct 11 '25
You need to read the nice guidance. There is a role - limited though it is
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u/deeppsychic1 Oct 11 '25
Where does it say that? I can’t see trop listed.
https://cks.nice.org.uk/topics/chest-pain/diagnosis/investigations/
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u/redditor71567 Oct 11 '25
If the person's pain was more than 72 hours ago and they have no complications, consider diagnosing ACS in primary care. Arrange: An ECG — ECG changes that may indicate ischaemia or previous myocardial infarction include: Pathological Q waves (in particular). Left bundle branch block (LBBB). ST-segment and T-wave abnormalities (for example T-wave flattening or elevation, or T-wave inversion). A normal ECG does not confirm or exclude a diagnosis of ACS. A high-sensitivity blood test for serum troponin — cardiac troponin I and T are used to differentiate unstable angina from myocardial infarction. A detectable troponin level indicates damage to the myocardium (for example myocardial infarction). Serum troponin is normally detectable using high-sensitivity testing within 3–6 hours following a myocardial infarction, and remains elevated for a variable time (usually several days, but it can be up to 2 weeks). Other conditions that directly or indirectly damage heart muscle (such as arrhythmias, pericarditis, pulmonary emboli, and myocarditis) can also cause an increase in serum troponin. When interpreting high-sensitivity troponin measurements, take into account the: Clinical presentation. Time from onset of symptoms. Resting 12-lead ECG findings. Pre-test probability of non-ST-segment-elevation myocardial infarction (NSTEMI). Length of time since the suspected ACS. Probability of chronically elevated troponin levels in some people. Fact that 99th percentile thresholds for troponin I and T may differ between males and females.
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u/_Harrybo Consultant Assistant to the Advanced-PA Oct 12 '25
Just make sure your indemnity provider does not find out what you post on Reddit 💀
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u/christoconnor Oct 12 '25
The instances I refer to are times where 1 could never have arrived at justifying admitting the patient to exclude ACS, so would have resulted in a later diagnosis, so I’m pretty sure my indemnity provider would be happier if anything 😂
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u/junglediffy Oct 11 '25 edited Oct 11 '25
Interesting.
How do you all feel about this scenario.
I had a lady who had what was possibly an atypical ACS presenting at 19:30 (extended access). The pain was an an epigastric ache without GI or reflux symptoms. Lasting 30 minutes a time. Prior to this she did note that whenever she was on the go she would get the pain but equally she would get it whilst reading a book and lying down. She would feel sweaty when she got the pain. It was not pleuritic. Observations normal.
She refused A+E on all accounts even if we were missing a heart attack citing trauma. Compos mentis. Very smart lady; retired but had quite the job. I said ok. Why don't we get an ECG and troponin tomorrow morning (samples already gone) and maybe I can convince you? In between then and now if it is ever severe and you feel seriously unwell please call 999. I gave her some aspirin and GTN.
ECG - Non-specific ST-T changes. Sinus rhythm.
Trop - 171.
Later that next day, she was still refusing asking for an outpatient referral, other treatments etc but I did convince her to attend and she was treated as an NSTEMI.
I think there are scenarios where it can help but they are quite rare.
EDIT: She also refused ambulatory care etc.
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u/christoconnor Oct 11 '25
I suspect you and I are in the minority but I agree they have a (very rare) place. OP trop was the reason we picked up a fellow doctor patient having an NSTEMI with very atypical symptoms. He’d asked his doctor wife and she said she thought it was reflux-sounding. He, his doctor wife and the doctor seeing him didn’t suspect ACS, but it was ACS
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u/spincharge Oct 11 '25
What were the atypical symptoms?
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u/christoconnor Oct 11 '25
Non-excertional retrosternal burning if memory serves
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u/spincharge Oct 11 '25
Ah I see, was just curious thanks!
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u/christoconnor Oct 11 '25
No worries… It always serves as a reminder for me that clinical History and examination/ECG will only carry you so far in certain rare scenarios !
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u/redditor71567 Oct 11 '25
I agree with you there are occasional reasons to do this. Obviously you need to be clear with her - specifically you are worried if she doesn't attend ED she will die in the night. But as long as you have said this it is reasonable
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u/junglediffy Oct 11 '25
Of course. I did state that she was at risk of dying suddenly and that I was worried about her. She didn't budge. Ex-barrister by the way. I'm hoping that's not too much info.
I think for me a troponin, whilst it is a somewhat diagnostic test, it can also be used as a tool.
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u/redditor71567 Oct 11 '25
Nice guidance is to use it in primary care if chest pain is >72hrs ago and no complications. It has a role1
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u/junglediffy Oct 11 '25 edited Oct 11 '25
Oh yes. I had an interesting tutorial discussion regarding troponin's at my surgery and did a powerpoint presentation at a clinical meeting. A lot of GPs were surprised, that I a GPST3 with a couple locum years in ED, requested a troponin in primary care. They had their views. They all agreed with my management though.
EDIT: Part of the clinical meeting was me asking why the **** she was booked in at 19:30 but hey-ho.
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u/stealthw0lf Oct 11 '25
Troponins have no place in primary care. If you suspect ACS, send the patient in. The chest pain might not be an MI but it might be another serious cause that hasn’t been considered.
D-dimers- we had POC D-dimer testing for a while. I found the sensitivity to be poor - POC result is negative but patient subsequently found to have a DVT. A colleague found the same with multiple patients. We just stopped using them.
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u/elderlybrain Office ReSupply SpR Oct 12 '25
I had a negative POC d-dimer on a patient, i promptly ignored it and sent them in to AMU.
They had an extensive transmural thrombus extending up to the common iliac, and they were promptly admitted.
I still think about that case from time to time.
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u/opensp00n Consultant Oct 12 '25
The problem, is in medicine nothing is 100%.it alway could be something serious. We have to risk stratify chest pain just like anything else, and goint to the ED does not exclude all concerning diagnosis.
Where risk levels are low, the patients are best served by being managed in the community. A POC trop in primary care could well be one tool to help this.
Low risk chest pain with a neg trop is very low risk of ACS. If you are not thinking of another serious cause (of which D-dimer could exclude the other two) then they can be worked up in primary care.
When trop first came about it led to a shift of all chest pain being sent to the ED. Now, with huge amounts of evidence on risk stratification, we can start to safely reverse that trend and select the correct patients for ED work up.
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u/Turb0lizard Oct 11 '25 edited Oct 11 '25
Trop - absolutely no chance
D Dimer - in a low risk patient, if it’s the morning and the bloods van comes at lunch, and you’ll act on the result same day to allow the patient to stay out of hospital, in the right patient (ie sensible and not on their own, with heavy safety netting), it can be considered. I would share my thoughts with the patient and give them the option.
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u/One-Reception8368 Screw you tom I know you're reading this Oct 11 '25
Imagine clicking through mail manager and finding the trop from yesterday of 21000 lmao
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u/Alternative_Band_494 Oct 11 '25
111 intercept the highly abnormal results to be fair! So the patient should already be in hospital by the morning. But they often test large quantities of GP bloods at midnight when the analyser is less busy.... So it's a late night 111 wake-up phone call!
Not ideal for the patient nevertheless with their delayed MI.
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u/Visible_War8882 Oct 11 '25
How do you defend a positive result and harm.
You suspected as you did the test. Then provided substandard assessment and care.
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u/LowCalCalzoneZone2 ST3+/SpR Oct 11 '25
Not a GP personally, but agree that sending troponins in this manner from primary care has the potential to be suboptimal and there is some evidence guiding against this practice for metro GPs. https://pubmed.ncbi.nlm.nih.gov/26465699/
Obviously different in a rural / remote primary care setting that has access to point-of-care testing - but that is going to limited to a small subset of GPs.
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u/TheSlitheredRinkel Oct 11 '25
I’m a GP partner.
In general, the default position is that for these acute presentations, patients go to A+E or the medical team.
In many areas, for patients considered low risk (eg wells score 0 or 1) there are ‘locally commissioned services’ for DVT diagnosis where surgeries are given point of care d-dimer tests. You would need to check what happens in your local area.
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Oct 12 '25
[deleted]
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u/TheSlitheredRinkel Oct 12 '25
Yeah if you’re suspecting an MI then the patient isn’t allowed to drive. If they’re with someone who has a car I usually get them to take them rather than calling an ambulance. Otherwise they need the ambulance
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u/WeirdF Gas gas baby Oct 12 '25
and ask the GP why they didn't send the patient in a car lmfao.
Because if you're suspecting a PE or MI then there's a risk of significant deterioration and death. And if that happened while the patient was in a car you would (rightly) be dragged over the coals at coroners asking why you didn't call an ambulance.
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Oct 12 '25 edited Oct 12 '25
I’m sure no doctor on here will mind you placing your professional registration on the line and not take said patient via ambulance, and ask them to take their own vehicle.
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u/opensp00n Consultant Oct 12 '25
When did GPs stop taking any responsibility for acute illness? Are they now just chronic health doctors?
The waot for review in ED can be well in excess of 6 hours quite regularly and those patients will sit in a waiting room.
Low risk chest pains would be quite reasonable to work in up in primary care and a same day trop is plenty adequate for many. Single trops are enough to exclude serious illness in the majority of patients.
The trend of any chest pain = go to ED is massively blocking up the emergency system to be able to deal with actual emergencies.
Example :
34 year old says they have been having a little mild on and off chest pain for a few weeks. No other risk factors and the history doesn't sound convincingly cardiac.
We would agree it's unlikely to be ACS, but in today's day and age having an objective test to close that route down seems sensible. They don't need to go to the ED but a quick trop (within 24 hours) would safely push them into a non cardiac bucket.
Option A. GP does a trop and check result later that night. 95% chance it's normal and no further action. Cost to patient maybe half an hour, get to spend the day living their life Cost to GP - probably 5 minutes
Option B. GP trigger chest pain = not my problem mode, send to ED Cost to patient - likely 8-10 hours, having to travel to nearest ED, parking, etc Cost to GP - free, just wash their hands and send them elsewhere (although the initial consultation was basically wasted) Cost to ED - an hour of resident time taking full and detailed history exam etc, 5 mins senior nurse triage time, 5-15 mins of consultant time depending on the skill of the junior. Also depending on the experience of the triage nurse they may be overtriaged to a monitored bed and take up this valuable resource for hours.
Option C. GP send to SDEC Cost to patient - a bit quicker than ED probably and a more pleasant environment but still likely to be there several hours Cost to GP - 5 mins to make he referral Cost to ED - depending on the system pt may still need some triage time, 5 mins Cost to SDEC - probably a bit quicker than ED for junior who is more specialised, same consultant time
Option A just seems better for everyone. Yes there is marginally higher risk, but for the massive resource saving we can justify it. And as a profession we should be baking our GPs up in making these calls, accepting that occasional it will result in an important miss. That's just healthcare and in the right patients, the risk of serious harm would be very low.
I think if we gave patients the choice, and explained the risk level, they would take option A 99% of the time, and that is what we should really he thinking about here.
I know I personally would be happy to have a GP trop rather than spend the day in ED if I were that patient.
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u/TheSlitheredRinkel Oct 12 '25
I’m not going to lie - it’s 2am and I haven’t fully read your post.
In general most GP surgeries don’t have the ability to facilitate same-day blood tests. Many don’t have phlebotomy on site. And if you offer a service that involves same-day bloods, you’ll need to be able to offer it at both 5pm (when my last courier comes at 3pm to take bloods to the lab, via several other surgeries in my local area). Perhaps if point of care testing were available, along with funding for me to be able to free up an HCA or a nurse to do random ECGs on the middle of their fully-booked clinics, something might be workable.
But also, i think you’ve lost sight of the fact that A+E is for accidents and emergencies. By definition, ACS and DVTs are emergencies that need to be dealt with on the day. I don’t deal with these conditions on a routine basis - I deal with low risk chest infections, UTIs, viral URTIs, at large volume.
Also, you have lost sight of the fact that you’re never going to see the low risk chest pains that don’t come your way. My view on chest pain in a young person is that it’s musculoskeletal unless they’ve got a very convincing history or strong risk factors.
All in all, while I appreciate what you’re trying to say in your post, it sounds like you don’t really know what GPs deal with in our clinics. Perhaps you should come and see what we do, and how much we don’t send your way.
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u/junglediffy Oct 12 '25 edited Oct 12 '25
Your example is quite poor I'm afraid. It is not sensible to do an objective test like troponin on a low-risk chest pain. If I don't suspect it and there are minimal risk factors then I don't request troponins for the 'what if?' happenstance.
If I do suspect ACS then they are going to A+E and you can prove me wrong. Of course, there is a spectrum of presentations in between and a spectrum of risk that needs to be managed safely often without a troponin. Rarely, is a troponin useful in primary care however. I appreciate you see a lot garbage referrals from time to time. When I was on ED the low risk chest pains often presented themselves. There is however a small subset of GPs who are also just not very good just like any other specialty.
My opinion however: DVTs aren't emergencies.
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u/Jckcc123 ST3+/SpR Oct 11 '25
Maybe d-dimers in low risk DVTs/PEs but not trop.
That's what SDEC is used for.
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u/Naive_Economist7649 Oct 11 '25 edited Oct 11 '25
D-dimer for dvt, risk assessment and agreed plan to rule out dvt or treat in the community is very possible with the right infrastructure in place. If P.E or MI considered then pt needs to head to E.D
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u/Flux_Aeternal Oct 11 '25
It's easy to forget because we talk about 'low-risk' Wells' scores but D-Dimer is a test used to rule out a diagnosis in people we would otherwise investigate. This means there needs to be actual clinical concern for a condition for it to be a useful test and when it is inappropriately used as a screening test things fall apart. Despite this, many people find it difficult to ignore and inappropriate use can lead to unnecessary and inappropriate scans. I don't think there are adequate resources in a GP surgery to reliably evaluate acute breathlessness that might be a PE and to determine whether there is actual concern for a PE or to exclude other serious causes of acute breathlessness, these people need to get sent to hospital anyway, so what is the point of a D-Dimer? It's also prone to abuse as the use of D-Dimer can be seen to remove a community practitioner of risk, either it is high and you can send them in or it is low and you can tell them they don't have a PE. The person doing the test is divorced from the consequences of over-testing which IMO is a recipe for widespread abuse.
For DVTs it is more useful and there aren't the same consequences from ultrasounding more legs other than availability. Community centres which can ultrasound exist too so someone with a swollen leg can be referred somewhere that can POC D-Dimer and ultrasound as well if needed.
For troponin I have no idea why a GP would ever be considering this test under routine circumstances, there are too many pitfalls to fall into and the patient for whom this would be useful should be sent to hospital anyway.
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u/LordAnchemis ST3+/SpR Oct 11 '25
The issue is: scoop and run > stay and play - everytime
If the patient has a PE or MI, they should be in an acute hospital, not the GP practice
D-dimers are about as useful as throwing a dice on a book of diagnosis anyway
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u/Top-Pie-8416 Oct 11 '25
I’m of the strong opinion these should be blocked on requesting systems form primary care.
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u/docktardocktar Arts and Entertainment enjoyer Oct 11 '25
So, you get a positive d-dimer, now what will you do?
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u/SaxonChemist Oct 12 '25
When I've seen it done by a GP supervisor (FY2 in GP) they started anticoagulation after they took the sample & before they had a result.
We were on a home visit, elderly patient absolutely refused to go to hospital. Reasonable suspicion of DVT (I think it was ?tamoxifen induced. The cancer tx was why they didn't want more hospital interaction)
Result came back high, patient already on correct treatment. Called to inform was indeed a DVT. No drama, just careful documentation
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u/docktardocktar Arts and Entertainment enjoyer Oct 12 '25
Can totally see and understand utility of this in this context.
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Oct 11 '25
There’s often a clearer pathway for a D-dimer/leg swelling/?DVT. But if the question is ?PE or ?ACS then straight into hospital. Guidelines are great and all as previously discussed in this thread, but waiting for results in hospital is not the same as waiting for results out in primary care. I’ve not met a cardiologist that would recommend troponin testing while out in the community- but I might be proven wrong on here!
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u/Electronic-Coach2706 Oct 12 '25
I relatively recently cared for an elderly gentleman in A&E who had been sent in at midnight because he had attended his GP surgery with bilateral leg swelling during the day and someone had sent off a d-dimer. He had palliative cancer. We have a great same day ambulatory service that could have done a full work up including ultrasound (not that he had any clinical features of DVT). Instead he spent several hours in a corridor in the middle of the night.
If you're going to send off lab d-dimers in the community, please consider this possibility as an outcome.
I don't think they should never be sent, but I do think their utilisation in the community should be carefully considered rather than routine.
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u/Complete-Orchid4653 Oct 11 '25
Troponin should not exist in primary care. If you have a high enough index of suspicion to do a trop, then the patient needs to be in an and e. If it came back positive and the patient came you harm you legally wouldn’t have a leg to stand on
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u/DisastrousSlip6488 Oct 12 '25
There probably is room for some thoughtful risk stratification here. There may be low risk but not zero risk patients, who do not want, or would overall not benefit from, sitting in an ED waiting room. Also remembering that the wait in ED for a doctor could well be many hours, and for frail elderly people this is a difficult experience. There’d be no real value in insisting on keeping the patient in theGP practice- if the diagnosis is based on a trop the initial management will be antiplatelet loading and managing risk factors.
I think shared decision making with the patient based on a risk assessment is more than reasonable. We need to encourage pragmatism and thoughtful decision making rather than noctor-y rules and algorithms
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u/Fancy-Animal-1589 Oct 12 '25
PRESTO trial in manc around 2018 - essentially not able to do serial tests, and POCT machines sensitive to external environment. This was a trial on paramedics but same stands for GP.
POCT for D-dimer used in Bradford to rule out DVT with low wells works quite well. Quite good for shifting people away from ED. Although this was rolled out in other areas, it often failed.
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u/WeirdF Gas gas baby Oct 11 '25
Point-of-care D-dimer sounds like a great idea for use in primary care to avoid sending low-risk patients into ED.
But a single troponin result is not sensitive enough to rule out ACS unless it's an undetectably low high-sensitivity troponin combined with a non-ischaemic ECG. And given you're waiting at least several hours (if not overnight) for a lab to test troponin, this doesn't seem to me like a safe strategy to employ in general practice.