Kidney function test: what it checks, how to read it and UAE price

A kidney function test, often shortened to KFT or called a renal profile, is a blood test that shows how well your kidneys are filtering and how well they are keeping the blood's salts, acid balance and minerals steady. It brings several results together, and they are read as a pattern rather than one number at a time.

What the test includes

Kidney panels differ between laboratories. The fuller versions draw on four groups of markers.

• Filtration. Creatinine, a waste product of muscle that healthy kidneys clear at a steady rate, and estimated GFR (eGFR), an estimate of how fast the kidneys filter, worked out from creatinine, age and sex with a validated equation.
• Waste from protein. Urea, reported as urea or as blood urea nitrogen (BUN), and the BUN/creatinine ratio, which compares the two.
• Electrolytes. Sodium, potassium, chloride and bicarbonate (also reported as total CO2): the salts that govern how much water the body holds, how nerves and muscles fire, the heart's rhythm and the blood's acid balance.
• Minerals. Calcium, magnesium and phosphorus, which bone, nerves and muscles depend on and which kidney disease can shift.

In Clare's panel, the lab measures creatinine, urea, sodium, potassium, chloride, bicarbonate, calcium, magnesium and phosphorus. Clare calculates eGFR from creatinine with a validated equation, and the BUN/creatinine ratio from urea and creatinine.

Two things a kidney function test usually leaves out are worth knowing about. The urine albumin-to-creatinine ratio (ACR) measures albumin leaking into the urine, and KDIGO, the international kidney guideline group, recommends testing people at risk with both a urine albumin test and an estimate of GFR, because the two pick up different kinds of kidney change. Cystatin C is a second filtration marker that a doctor may add when creatinine is likely to mislead, for example in very muscular people. Some UAE kidney profiles also add uric acid.

Who usually asks for it

Doctors order kidney function tests to screen, to follow a known condition and to check the effect of medicines. NICE and KDIGO advise testing people with:

• diabetes or high blood pressure
• heart or blood vessel disease
• a previous episode of acute kidney injury
• kidney stones that keep coming back, or another structural problem in the urinary tract
• a condition such as lupus that can involve the kidneys, or gout
• a family history of kidney failure or inherited kidney disease

NICE also advises checking kidney function at least once a year in people taking medicines that can affect the kidneys, such as long-term anti-inflammatory painkillers (NSAIDs) or lithium, and NIDDK, part of the US National Institutes of Health, advises people with diabetes to be checked every year. Early kidney disease usually causes no symptoms, which is why blood and urine tests are how it is found.

How to prepare

• Fasting. A kidney panel on its own usually needs no fasting. When it is drawn with tests that do, such as fasting glucose, follow the fasting instruction for the whole draw.
• No meat for 12 hours. NICE advises adults not to eat any meat in the 12 hours before a blood test for eGFR. KDIGO cites a study in which a cooked meat or fish meal raised creatinine by about 20 µmol/L (0.23 mg/dL), with the peak 2 to 4 hours after the meal, enough to lower the eGFR noticeably.
• Supplements and diet. Creatine supplements and high-protein diets can raise creatinine without any change in how the kidneys work. Tell the person taking the sample what you take; whether anything changes before a test is a question for your doctor.
• Exercise. Very hard exercise is one of the things that can change creatinine without any change in filtration, so avoid an unusually hard session the day before.
• Hydration. Dehydration raises urea and concentrates the blood, so drink normally unless you have been told otherwise.
• At the draw. Potassium is easy to raise by accident. A tight tourniquet, clenching or pumping the fist, a damaged (haemolysed) sample, or a delay before the sample is processed can push it up while the potassium in your body is normal. NICE advises that samples reach the laboratory and are processed within 12 hours.
• Medicines. Some blood pressure medicines (ACE inhibitors, ARBs, spironolactone), anti-inflammatory painkillers and the antibiotic trimethoprim can raise potassium, and diuretics, steroids and antacids can shift electrolytes. Mention everything you take.

How the markers are read together

No single number on a kidney function test means much on its own. Doctors read the results as patterns, and against earlier results where they exist.

Creatinine and eGFR

These move in opposite directions: when creatinine rises, eGFR falls. Because creatinine comes from muscle, the estimate is less reliable at the extremes. A very muscular person can have a higher creatinine and a lower eGFR with healthy kidneys, and someone with little muscle can have a flattering eGFR. NICE also lists pregnancy, malnutrition, protein supplements and a sudden kidney injury as situations where eGFR is less reliable, and this is where a doctor may add cystatin C.

Urea and the BUN/creatinine ratio

Urea rises when filtration falls, but also with dehydration, a high-protein diet and some medicines, and it falls with low protein intake and liver disease. The BUN/creatinine ratio is the classic way to separate dehydration from a problem in the kidney itself. It is a clue rather than an answer: a 2026 review of nine studies found its accuracy for telling these causes apart was limited.

Sodium, potassium, chloride and bicarbonate

Sodium and chloride mostly reflect the balance of water and salt, and they shift with dehydration and with medicines such as diuretics. Potassium depends heavily on the kidneys to remove it, and on medicines, so it is watched closely when kidney function is reduced. Bicarbonate is the blood's main buffer. As filtration falls, the kidneys generate less of it, so a low bicarbonate alongside a low eGFR is a recognised pattern.

Calcium, magnesium and phosphorus

Phosphorus tends to rise when the kidneys are not clearing it well. Calcium is read with albumin, because about half the calcium in blood is carried on proteins, mainly albumin, so a low albumin can make calcium look low. Magnesium completes the mineral group.

One result, or a pattern that lasts

KDIGO defines chronic kidney disease as a change in kidney structure or function that lasts at least three months, and classifies it by both filtration and urine albumin. Its guidance is to repeat an unexpected result to confirm it, and not to assume a long-term problem from a single abnormal value, which could reflect a short-lived kidney injury. NICE advises repeating a low eGFR within two weeks in an adult not tested before, and notes that kidney disease does not progress in many people.

Why it matters in the UAE

Diabetes is one of the main reasons guidelines advise regular kidney testing, and it is common in the UAE. The IDF Diabetes Atlas estimates that about 1.3 million adults aged 20 to 79 in the UAE were living with diabetes in 2024, and NIDDK advises a kidney check every year for people with diabetes.

Ramadan is the other UAE-specific point. A 2026 UAE study notes that Ramadan fasting has been found safe for most people with chronic kidney disease, and that the risk depends on the stage of the disease and other conditions. A UAE working group has built a risk score, the RaK score, to help doctors judge who can fast safely, and a low eGFR is one of its parts. For anyone with a kidney condition who plans to fast, a recent kidney function test is part of that conversation with a doctor.

Price

When we read public prices on 11 October 2026, a kidney function test cost from 89 to 900 at six UAE providers. What is included varies widely: some panels list little more than urea and eGFR, others add electrolytes, minerals and uric acid, and urine albumin may be a separate test. VAT is rarely stated, some are offer or "from" prices, and home collection can add a fee.

Related tests

A urine test, which includes protein in urine, shows what the kidneys are letting through. The HbA1c and diabetes test matters because diabetes is one of the main risk factors for kidney disease; HbA1c, glucose and insulin: reading them together explains how those markers are read. And Comprehensive blood test in Dubai: what to expect notes how dehydration in a Dubai summer can nudge creatinine upwards.

Why the numbers mean more over time

Kidney results are most useful as a series. Creatinine varies by around 5% from test to test through normal biological and laboratory variation, so small moves are expected. NICE treats a rise in creatinine of more than 20% as a meaningful drop in function when eGFR is above 90, and KDIGO treats an eGFR change of more than 20% between tests in someone with kidney disease as more than normal variation. How often the test is repeated depends on the person: KDIGO suggests at least once a year for people with chronic kidney disease, NIDDK suggests yearly for people with diabetes, and others agree an interval with their doctor. A steady eGFR across several years says something no single result can.

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