Red urine, yellow urine, red urine, yellow urine: Managing Haematuria

The For Kidneys Sake podcast series is brought to you by Imperial College Healthcare NHS Trust and North West London Integrated Care Board (NWL NHS).

In this episode, consultants Prof Jeremy Levy and Dr Andrew Frankel, both nephrologists at Imperial College Healthcare NHS Trust, discuss the significance and management of microscopic (non-visible) haematuria in primary care. They provide practical guidance for general practitioners on how to interpret urine dipstick findings, the appropriate steps for investigation, and when specialist referral is warranted. The conversation emphasises the importance of not overlooking persistent haematuria, while also acknowledging the challenges in balancing appropriate concern with unnecessary anxiety or over-referral.

The clinicians explore differential diagnoses, such as glomerulonephritis, IgA nephropathy, and hereditary conditions like thin basement membrane disorder or Alport syndrome. They stress the role of imaging, the presence of proteinuria, and age-based referral pathways in forming a management plan. A key theme is the long-term follow-up of patients with isolated haematuria, even when kidney function is normal, to monitor for progression via regular kidney health checks in primary care. The discussion is informative and grounded in real-world experience, aiming to clarify an area that is often perceived as ambiguous in general practice.

Three Main Takeaways:

1. Persistent microscopic haematuria warrants investigation and should not be dismissed, particularly when confirmed on repeat testing and associated with other findings such as proteinuria.
2. All patients with confirmed haematuria should undergo a renal ultrasound, and referral decisions should be guided by age and associated symptoms or findings. Generally, referrals are made to urology if the patient is over 50, and to nephrology if the patient is under 50 or if proteinuria is present.
3. Even when no serious underlying condition is identified, patients with isolated haematuria require annual monitoring, including blood pressure, kidney function (GFR), and urine albumin-to-creatinine ratio, ideally recorded in primary care records to ensure lifelong follow-up.

Resource Links:
NICE GUIDELINES [NG203] chronic kidney disease: assessment and management Overview | Chronic kidney disease: assessment and management | Guidance | NICE

Northwest London CKD guidelines for primary care Chronic kidney disease (nwlondonicb.nhs.uk)

The purpose of this podcast is to inform and educate health care professionals working in the primary care and community setting. The content is evidence based and consistent with NICE guidelines and North West Guidelines available at the time of publication.

The content of this podcast does not constitute medical advice and it is not intended to function as a substitute for a healthcare practitioner’s judgement.

Produced by award-winning media and marketing specialist Heather Pownall of Heather's Media Hub

Chapters

• 0:00 Understanding Haematuria: Definition and Importance
• 2:47 Testing and Diagnosis of Haematuria
• 6:50 Referral Guidelines for Haematuria
• 7:21 Identifying Underlying Causes of Haematuria
• 11:20 Management and Follow-Up of Haematuria Patients

Transcript

Jeremy Levy
So hello again, I'm Jeremy Levy, consultant nephrologist at Imperial College Healthcare NHS Trust.

Andrew Frankel
And I'm Andrew Frankel, also a consultant nephrologist working at Imperial College Healthcare NHS Trust.

Jeremy Levy
It's fantastic to be with you again Andrew. All kidneys today For Kidney Sake. We're going to be talking about haematuria in this podcast. Of course, haematuria, as I hope our audience all knows, means blood in the urine. Here we're to be thinking about what should be done about this in primary care. Of course, in the majority of cases this is not visible or what we used to call macroscopic haematuria and is normally non-visible, people can't see it, or microscopic haematuria, and it's usually only identified, isn't it, because people have had a dipstick, a urine dipstick, for some reason.

Andrew Frankel
Yes, Jeremy, and I think it's good to start our discussion to highlight that microscopic or non-visible haematuria can be identified or assessed by urine dipstick or urine analysis, and anything equal or above one plus of blood should be considered to be significant and investigated. Now, you can also identify blood in the urine, non-visible haematuria, from microscoping a urine MSU sample and that is occasionally reported by the lab as showing red blood cells. However, this has a high false negative rate due to the time it takes to get the sample to the lab which is associated with degradation of the red blood cells and therefore it's not the best method of identifying or screening people for microscopic haematuria.

In the old days we used to microscope fresh samples of urine as nephrologists, but that is not undertaken in the laboratories. So for the rest of this podcast, let's just stick to urinalysis or dipstick results.

Jeremy Levy
Yeah, that's right, Andrew. We haven't microscope urine ourselves for many years, sadly, haven't we? So we've both been engaged with GPs and primary care physicians and primary care teams for a long time. And this is a really common issue, isn't it? The presence of non-visible haematuria. So actually, initially, when should somebody have the test being done and why might you do it?

Andrew Frankel
Yeah, I suppose that the key questions for primary care are when to test the urine and how to respond to an abnormal result. You and I would certainly agree and we highlighted this in one of our previous podcasts with the title, chronic is not wicked or awful, as your teenager might tell you. In this podcast, we were clear that urine testing is really important in all patients with a diagnosis of kidney disease and it isn't just about measuring the albumin-creatinine ratio. It is important not to just label someone with CKD because the finding of blood and protein in the urine could signify a more active inflammatory disease process such as glomerulonephritis but requires more urgent investigation. However, many individuals have urine dip testing as part of a routine health examination for insurance purposes

or when registering with a GP practice. And more and more people buy commercial health screens and these may have detected blood in the urine which may be the first indication of a potential problem.

Jeremy Levy
And of course, that's right, Andrew, but but it can be a false positive result as well, can't it? A urine dipstick for blood. And it can be caused, of course, in women who having their periods. And it can be caused by a urinary infection. But we also don't want it to be ignored as GPs and primary care saying it's always due to a urinary infection. So it is always to be aware of when the test is done and why it might be positive for other reasons. So a repeat urine test is often going to be important to make sure it's genuinely there and as you say more than one plus is important not just a trace of blood on a urine dipstick. But if it is persistent people do have persistent non-visible haematuria in general there's a recommendation isn't there to consider a referral either to urology urology to exclude most importantly bladder cancers or kidney cancers or to refer to nephrology to exclude an intrinsic kidney, a renal cause for the haematuria. So for GPs, this is often the dilemma, it? And the question, and we're asked this very frequently, does everybody need to be referred to urology, even if they're 20 or 30 years old? Or how should the GP decide which route to go down? What's your approach and your advice?

Andrew Frankel
Yes, this is an area that actually does cause some concern or worry in general practice as to where the referral should go once you've identified microscopic haematuria. And there is a tendency in guidelines to have an age cut off which is above 50, urology first, below 50, nephrology first. This, as you've said, is because you only track cancers are rare in those under 50. It is important though to understand that some people can still develop urological cancers even under the age of 50 and also that there are what I call surgical causes of haematuria such as stone disease that can occur in younger people. And therefore a starting point is that all people with confirmed microscopic haematuria should have an ultrasound or imaging of their kidneys irrespective of age. Having ordered the ultrasound, then you can proceed on the basis of age. Over 50 refer first to urology, under 50 to nephrology. However, there's one more caveat. That is, if they have symptoms of loin pain or weight loss that are concerning to you, you may, and they're under 50, you may still want to fire off a urological referral. And similarly,

If they are over 50 and they've got protein neuro with their haematuria, you may wish to fire off the referral to both urology and nephrology at the same time.

Jeremy Levy
That's exactly what I say as well Andrew. Everyone needs an ultrasound scan. People think stones for example always cause symptoms but they don't and they're a common cause for haematuria. So over 50 with their ultrasound scan mostly to urology, under 50 years of age mostly to nephrology and if there's proteinuria with haematuria definitely we want to see those people. But we should also stop to think shouldn't we about why we're actually concerned about this, why we as nephrologists are concerned about microscopic haematuria. Why do we want to see these people at all? Especially if they've got completely normal GFRs of over 90 and no proteinuria. What are we adding to this?

Andrew Frankel
Of course, it's really important to understand why we're doing these things, as well as trying to explain to people what needs to be done.

The key issue in this context for the patient and at the back of our minds is whether microscopic haematuria indicates that that individual is at risk of kidney functional decline in the future. And it also is important to make a diagnosis so we can give the patient advice for their future, their self-care, and as you'll see, issues potentially for their family and children.

Jeremy Levy
Yeah, that's really important. Making a diagnosis really is beneficial and important, isn't it? Advice for the patient, advice for the GP, advice for families. So it's important not to ignore these things. So let's focus on the the renal, the nephrological causes of haematuria, why we want to see this young person with normal GFR, no proteinuria. What do we actually do? And then what do we say to them?

Andrew Frankel
So we're looking to pick up people who've got microscopic haematuria in the context of inflammatory kidney disease or glomerulonephritis. It wouldn't be our expectation that primary care would make this diagnosis, but there are some simple features that would go along with this. Most particularly, as we've said on a number of occasions, the presence of albuminuria. Well, they may have clinical features that could suggest a systemic inflammatory disease such as SLE or vasculitis. Where such diagnoses are possible, an immunological screen is helpful, including immunoglobulins, ANA, anchor testing. However, I need to be clear that if there is a suggestion of an inflammatory disorder, it will be secondary care's responsibility to order the appropriate investigations, such as the tests I've described, and indeed considering whether to proceed to a kidney biopsy.

Jeremy Levy
That's really important, isn't it, Andrew? Because actually if a GP or primary care team have actually thought that there might be an inflammatory issue, actually that needs an urgent referral. If somebody was suddenly worried about lupus or vasculitis, that's not something that should be sitting nine months waiting to be seen. So if that has been a consideration, needs an urgent referral. What other factors do you think are important when the GP should consider what information they're going to tell the person or tell the GP when they've identified microscopic haematuria.

Andrew Frankel
So I think family history is important here and it's always worthwhile asking the patient whether they've got a history of a close relative that required kidney replacement therapy because that increases the concern that the patient may have microscopic haematuria that could progress over time to end stage kidney failure and that there may be a hereditary structural kidney condition such as polycystic kidney disease and of course there are many others.

Jeremy Levy
That's right Andrew and asking people obviously not just is there a history of haematuria but that that question that you said is there a history of anybody in the family having ended up needing a dialysis or a kidney transplant. Our audience isn't stupid we should talk about that the disease is not just polycystic kidney disease in fact the commonest inherited familial condition that can cause haematuria alone is this disorder of the glomerular basement membrane, sometimes called thin membrane disease or thin basement membrane disorder. And that's where the collagen in the glomeruli, the filtering units of the kidney becomes abnormal because of an inherited defect in these genes. We sometimes use the phrase Alport syndrome, but there are a spectrum of disorders now where the filtering unit in the glomeruli is abnormal. And these are important because even if they don't cause kidney failure, they can run in families. And then the other major kidney condition that we think about with haematuria is this condition that our audience will have heard of IgA immunoglobulin A nephropathy which actually is very common. This one does not usually run in families at all but we used to think of it as a rather benign disease that rarely caused sort of end-stage and progressive kidney failure but we now know that that's in fact not the case and a very significant number of people but very slowly can go on to get severe kidney impairment, but it may take 10, 20 years, but that's really important to know about. it is really important to make a diagnosis so that we can actually manage these long-term issues, discuss with people, potential effects on their children. But also we have treatments for these conditions. Again, 20 years ago, we didn't have any treatments, but we really do now. So I suppose the other issue to talk about is what advice do we then actually give? The patient and primary care when we've seen somebody with isolated haematuria. Do they need follow up? Should we see them in our clinics? Do they need to see their GPs? mean, some of these people were in kidney clinics coming once a year for many years. What's your view now about how we should actually manage these patients?

Andrew Frankel
So this is the individual who's just got isolated microscopic haematuria. They may have had a diagnosis made. And as you've highlighted, although we used to consider it to be benign, if you follow these people up over many years, a proportion progressed to CKD. However, this almost always occurs in conjunction with the appearance of albuminuria that will or pre-date declining kidney function. That's the critical issue. Therefore we simply need to use our blood tests to exclude aggressive conditions, take a careful history, look hard for proteinuria, but then my advice is that if a person has pure isolated haematuria it's perfectly reasonable to discharge them back to primary care. But the important point is that they have a kidney health check that's blood for GFR, urine assessment for albuminuria and a blood pressure assessment on an annual or perhaps biannual basis. And this needs to continue for life. And the monitoring needs to be recorded in GP records, which is why if they've got microscopic haematuria, it's worth recording and coding them as CKD because that will ensure that you are reminded to call them back for their annual kidney health check. Otherwise they can get lost in the system and there's a small risk of them presenting in later life with advanced kidney disease.

Jeremy Levy
I completely agree Andrew, but I really emphasise with the patient that so that they know that as well. This is critically important that they need a once a year kidney health check, that they need that blood test, the blood pressure and the urine albumin creatinine ratio, the measure of albuminuria. Because then also I say to the patient and to primary care, when do we when do we want to see the patient again? And exactly as you said, that's that's if they develop proteinuria, that's a warning sign, a bad prognostic sign. So if they only had microscopic haematuria to start with and then their ACR goes up to 20 and to 50, we want to see the patients again who are developing proteinuria and certainly with that ACR is above 50 because we now recognise that might be a threshold when we do want to intervene with a variety of treatments that we now have. So refer back to a kidney specialist if there is the development of proteinuria that would be true regardless of the underlying causes. But we are often left aren't we saying to patients yes you've got haematuria we've excluded serious illnesses that are going to progress rapidly but we're still not sure if you've either got this condition thin membrane nephropathy or IgA and we might need just to leave this uncertainty. The diagnosis isn't completely clear but we know that they're in a good prognostic group but they do need their annual kidney health check. And that's an important message to get across, isn't it?

Andrew Frankel
Absolutely.

Jeremy Levy
Andrew, I think this has been a great conversation. Thanks again, as always. I think there are three messages that I'm remembering and hope that our colleagues are remembering. Always look for proteinuria in somebody where we found haematuria and measure the urine-albumin-cracknein ratio. They should have done a urine dip at the beginning, not just measure the urine ACR because the presence of blood and proteins is important.

All patients with haematuria need an ultrasound scan of their kidneys and bladder. That would be very important. Referral to urology for people over the age of 50 or with any symptoms that might be relevant that suggest a structural kidney problem. Otherwise, we do want to see them to provide investigations and provide advice. And I'm allowed a fourth memory point, I think a fourth point. We do want to try and make a diagnosis, but it's not always possible or certain, then all these people do need an annual kidney health check which can often be done in primary care but really important to continue that essentially for life to make sure they don't develop proteinuria.

Andrew Frankel
Thank you very much, Jeremy. Of course, I completely agree with you. That summary is absolutely clear and consistent with what I would advise primary care.

Jeremy Levy
Great chat Andrew, bye for now.

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