7 Signs You Should See a Nephrologist — Not Just Your GP

Your general practitioner is the right first stop for most health concerns, and a good GP manages a great deal of kidney-related care competently. But the kidneys are complex organs, and there are specific situations where the depth of expertise a nephrologist brings genuinely changes outcomes. Knowing when to escalate from your GP to a specialist can protect kidney function that, once lost, rarely comes back. Here are seven clear signs it is time to see a nephrologist.

1. Protein or blood in your urine

A urine test showing protein (proteinuria) or blood (haematuria) is one of the most important early warning signs of kidney disease. Healthy kidneys keep protein and red blood cells in the bloodstream; when they leak into the urine, it often means the kidney’s delicate filtering units are damaged or inflamed. Foamy urine is often the first visible sign of significant proteinuria, while visible blood in urine always warrants prompt evaluation.

A GP can detect these findings, but a nephrologist can determine why they are happening. This may involve specialised urine quantification, blood tests for immune and inflammatory conditions, and in some cases a kidney biopsy, which only a nephrologist can arrange and interpret. Identifying the specific cause early — whether glomerulonephritis, early diabetic damage, or another cause — often allows treatment that halts the damage. According to the KDIGO 2021 Glomerular Diseases Guideline, early diagnosis significantly improves outcomes in most glomerular conditions.

2. An eGFR below 60

Your estimated glomerular filtration rate (eGFR) measures how well your kidneys filter. A value persistently below 60 mL/min/1.73m² for three months or more defines chronic kidney disease (CKD). While a mildly reduced eGFR may be monitored by a GP, anything that is low or falling deserves specialist evaluation.

A nephrologist can stage the disease accurately, identify reversible contributors, and put in place strategies to slow progression, including specific medications proven to protect kidney function. The KDIGO 2024 CKD Guideline identifies an eGFR below 60 as the threshold for specialist-level monitoring in most clinical pathways.

3. Creatinine trending up over multiple tests

A single raised creatinine reading can have many innocent explanations, but a creatinine that climbs steadily across several tests tells a different story. This upward trend — also visible as high creatinine on repeat testing — is a signal that filtration is progressively declining.

GPs may see these results spread across different appointments and not always connect the dots. A nephrologist looks specifically at the trajectory, investigates the rate of decline, and acts before significant function is lost. Timing matters enormously: intervening early in a trend is far more effective than reacting once function is already severely reduced.

4. High blood pressure that stays high despite medication

Blood pressure and kidney health are deeply linked, each capable of damaging the other. If your blood pressure remains high despite taking two or three different medications, this is called resistant hypertension, and it is a recognised reason for nephrology referral. Left unmanaged, it leads to hypertensive nephropathy — a progressive form of kidney damage.

A nephrologist can investigate whether an underlying kidney or hormonal problem is driving the resistance. They can also fine-tune a treatment combination that controls pressure while simultaneously protecting the kidneys, a balance that requires specialist judgement. The ESC/ESH 2023 Hypertension Guidelines recommend nephrology referral for resistant hypertension when secondary causes have not been excluded.

5. Diabetes with signs of kidney involvement

Diabetes is the leading cause of kidney failure worldwide. Many people with diabetes are managed well by their GP and diabetes team, but once the kidneys show signs of involvement — such as protein appearing in the urine or a falling eGFR — specialist input becomes valuable. Diabetic nephropathy can be slowed substantially when identified and treated early.

A nephrologist works alongside your existing care to slow diabetic kidney disease using treatments that go beyond blood sugar control, including SGLT-2 inhibitors and finerenone, which have demonstrated significant kidney-protective effects in large clinical trials. The DAPA-CKD trial (Heerspink et al., 2020) showed dapagliflozin reduced the risk of a sustained decline in eGFR by 39% in patients with CKD and type 2 diabetes.

6. A family history of kidney disease

Some kidney conditions are inherited, the best known being polycystic kidney disease (PKD). If close relatives have had kidney disease, kidney failure, or have needed dialysis or a transplant, your own risk is higher than average.

A nephrologist can assess your inherited risk, arrange appropriate screening such as imaging or genetic evaluation, and establish a monitoring plan tailored to your family history. Autosomal dominant PKD affects approximately 1 in 1,000 people globally and is the most common monogenic kidney disease, according to a comprehensive review in the Lancet (Torres et al., 2019).

7. Recurrent kidney stones

A one-off kidney stone is common and usually managed without a specialist. But recurrent stones are different. Repeated episodes suggest an underlying metabolic cause that, left unaddressed, will keep producing more stones and may gradually harm the kidneys. The EAU Guidelines on Urolithiasis (2023) recommend a full metabolic work-up after a second stone episode.

A nephrologist can investigate your blood and urine chemistry and the stone composition to identify exactly why kidney stones keep forming. This allows a targeted prevention plan — whether through dietary changes, fluid strategy, or medication — that a general approach cannot match.

Reassurance and next steps

Seeing this list, it is natural to feel a flicker of worry, but the message is genuinely reassuring: kidney disease, when caught early, is one of the most manageable chronic conditions in medicine. The kidneys give us time, and specialist care uses that time well. The patients who do best are almost always those who acted on an early sign rather than waiting.

If you recognise any of these seven signs in your own health, a consultation with a nephrologist is a sensible and proactive step. Dr. Juan Luis Villaro Gumpert provides specialist kidney care in Valencia, offering clear assessments and personalised plans in English. An early conversation could be the most valuable thing you do for your long-term kidney health.

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References

1. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024. kdigo.org
2. KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney Int. 2021;100(4S):S1–S276. kdigo.org
3. Heerspink HJL, et al. Dapagliflozin in Patients with Chronic Kidney Disease (DAPA-CKD). N Engl J Med. 2020;383:1436–1446. PubMed 32970396
4. Mancia G, et al. 2023 ESH Guidelines for the Management of Arterial Hypertension. J Hypertens. 2023;41(12):1874–2071. escardio.org
5. Torres VE, et al. Autosomal dominant polycystic kidney disease. Lancet. 2019;393(10174):919–935. PubMed 30093348
6. EAU Guidelines on Urolithiasis 2023. European Association of Urology. uroweb.org