Creatinine test: normal range, high creatinine and what it means

A creatinine test measures creatinine in your blood, a waste product of muscle that the kidneys clear at a steady rate. Because the kidneys are what remove it, the level is a practical window on how well they are filtering, and it is the number eGFR is calculated from. A result means most when it is read with eGFR, with your build and with your own earlier results.

What creatinine is

Muscles use a compound called creatine to supply energy, and creatinine is the waste product it breaks down to. Creatinine passes into the blood, the kidneys filter it out, and it leaves in the urine. When filtering slows, less creatinine leaves and the level in the blood rises.

How much creatinine a person makes depends mainly on muscle mass, and also on diet, age and activity. A figure that is ordinary for one person can be high for another, and women, who on average carry less muscle, usually run lower than men.

Creatinine also has a blind spot: in early kidney disease it can stay inside the normal range, so a normal result does not by itself show that the kidneys are healthy.

Normal range

Results come in micromoles per litre (µmol/L), the SI unit, or in milligrams per decilitre (mg/dL). To convert, multiply mg/dL by 88.4. Common adult reference ranges are:

	µmol/L	mg/dL
Men	62 to 115	0.7 to 1.3
Women	44 to 84	0.5 to 0.95

Ranges vary by laboratory and method, and with age, sex and body size, so the range printed on your report is the one to read against.

What a high result usually points to

A creatinine above the range, or clearly above your usual level, usually points to the kidneys filtering less, or to something outside the kidneys pushing the number up.

• Kidney causes: reduced blood flow to the kidneys, infection, injury, a blockage in the urinary tract, or long-term kidney disease.
• Conditions that affect the kidneys, such as diabetes and heart failure.
• Causes outside the kidneys: dehydration, intense exercise, a diet high in meat, and muscle injury or breakdown.
• Pregnancy complications such as pre-eclampsia.

One high result does not diagnose anything. A doctor typically repeats the test, looks at eGFR and at a urine test for albumin, which KDIGO recommends alongside GFR, and asks about recent exercise, meals, fluids and medicines. A short-lived dip looks the same as a lasting one on a single test, and chronic kidney disease means changes lasting at least three months; NICE recommends confirming a new eGFR below 60 with a repeat test within two weeks. Where muscle mass makes creatinine misleading, a doctor may add cystatin C, a second filtration marker. Talk to a doctor about a high result, with the result in front of you.

What a low result usually points to

Low creatinine is uncommon and usually reflects less muscle rather than anything about the kidneys: a long illness, a nerve or muscle condition, muscle loss with age, or poor nutrition. Serious liver disease can also lower it.

What moves it

• Muscle mass. Very muscular people make more creatinine and people who have lost muscle make less; NICE advises caution in reading eGFR at either extreme.
• Meat and fish. A cooked meat or fish meal raises creatinine for some hours. KDIGO cites a rise of about 20 µmol/L (0.23 mg/dL), peaking two to four hours after eating.
• Exercise and fluids. Intense exercise and dehydration both raise it.
• Diet and supplements. KDIGO lists high-protein, ketogenic, vegetarian and low-protein diets, creatine supplements and anabolic steroids among things that change creatinine without any change in filtering.
• Medicines. Cimetidine, famotidine, trimethoprim and cefoxitin are among those that affect the result, and KDIGO notes that medicines which reduce the kidneys' secretion of creatinine change the level without changing filtration.
• Pregnancy. NICE notes that eGFR is less reliable in pregnancy.
• Handling. NICE asks that samples reach the laboratory and are processed within 12 hours.

Preparing for the test

Creatinine itself needs no fasting, but it is usually drawn alongside tests that do, such as fasting glucose, so follow the instructions for the whole panel.

• Avoid meat in the 12 hours before the draw, as NICE advises for an eGFR test.
• Keep the day before light, since intense exercise can raise creatinine.
• Drink water as you normally would.
• Tell the person taking the sample about creatine or protein supplements and any medicines. Keep taking prescribed medicines unless your doctor has told you otherwise.

How Clare's panel handles it

In Clare's panel, creatinine is measured by the lab. Clare then uses it in two calculated results: eGFR, worked out from creatinine with age and sex, and the BUN/creatinine ratio, which sets urea against creatinine. When Clare opens, members will see the three together, with their past results alongside.

Why it matters in the UAE

A study of 491 UAE nationals in Al Ain with, or at high risk of, cardiovascular disease, all with normal filtering at the start, found that 11.4% developed an eGFR below 60 lasting three months or more over nine years, a little over 1% a year. Older age, coronary heart disease, diabetes and smoking were the independent risk factors. It was a high-risk group, not the general population.

On Ramadan, a 2020 study of people with chronic kidney disease in Al Ain found that fasting was not linked to their eGFR after the month once age and starting eGFR were accounted for, though 74 of them had a follow-up test. A 2024 review of 32 studies found inconsistent effects of fasting on creatinine and eGFR, from studies with significant limitations. If a sample is drawn during a fast, mention it, since dehydration raises creatinine.

Price

Creatinine is usually sold within a kidney function test rather than on its own. When we read public prices on 11 October 2026, a kidney function test cost from 89 to 900 at six UAE providers. Five of the six were 250 or less, and the top of the range was a specialised package. VAT was rarely stated, some figures were offer or "from" prices, and home collection can add a fee.

Related tests

Creatinine is read with eGFR, which is calculated from it; with urea (BUN) and the BUN/creatinine ratio, which help separate a kidney cause from dehydration; and with urine protein, since albumin in the urine can be a sign of kidney damage while creatinine is still in range. For what to expect from a full panel, including preparation, see Comprehensive blood test in Dubai: what to expect.

Why the number means more over time

Creatinine is fairly stable in a healthy person, so the most useful comparison is with your own earlier results. NICE allows about 5% either way for normal variation, and when eGFR is above 90 it treats a rise of more than 20% as a sign of a real fall in kidney function. KDIGO recommends checking GFR at least once a year in chronic kidney disease, and NICE recommends testing adults with diabetes, high blood pressure or heart disease for kidney disease. A creatinine that edges up across several tests says more than one reading just over the line.

Clare is opening with a waitlist at clare.health.