Urea is the waste your liver makes when it breaks down protein, and your kidneys flush it out in urine. A low result is common and often harmless, usually from eating less protein or drinking a lot of water, and it's also typical in pregnancy. A high result can come from dehydration, a high-protein diet or the kidneys filtering more slowly, so we read it with creatinine and eGFR. The lab range is 2.3 to 10.0 mmol/L. Urea is part of the Vively Baseline Health Check, which comes with the $99 a month membership, and the lab tests are Medicare-rebated for eligible members.
Urea is one of 70+ markers in Vively's Baseline Health Check, read alongside your creatinine, eGFR and electrolytes so you can see what is driving it.
Every marker in range? Get your $99 back. T&Cs apply.Want to save 25%? Try our 4-Month Reset insteadUrea is a waste product your liver makes from protein. When your body breaks down amino acids, the building blocks of protein, it strips off their nitrogen as ammonia. Ammonia is toxic, so the liver converts it into urea, which travels in your blood to the kidneys and leaves your body in urine.
Your kidneys filter urea out of the blood, then reabsorb some of it. How much they reabsorb depends on how hard they are working to hold onto water. That is why urea is so sensitive to hydration.
In Australia, urea is reported in millimoles per litre (mmol/L). US labs report the same waste product as blood urea nitrogen (BUN), in milligrams per decilitre (mg/dL).
A urea test shows the balance between how much urea your liver makes and how much your kidneys clear. Three things drive that balance:
Because everyday habits shift it so easily, urea is a weak kidney test by itself. Creatinine and eGFR measure kidney filtering far more directly.
Kidney disease rarely causes early symptoms. The Australian Institute of Health and Welfare estimates about 1 in 10 Australian adults have signs of chronic kidney disease, most without knowing. Tracking urea with creatinine and eGFR is an easy way to watch your kidney health.
For most adults, urea sits between about 2.5 and 7.8 mmol/L, with a higher upper limit in older adults.
| Range | |
|---|---|
| Typical lab reference range (adults) | About 2.5 to 7.8 mmol/L |
| Older adults | Often a higher upper limit, up to about 10 mmol/L at some labs |
| Vively optimal range | None set. We read urea against your creatinine, eGFR and previous results |
Urea tends to creep up with age as kidney filtering slows a little. Use the range on your own report, and compare the number with your previous results.
A high urea most often means you were a little dehydrated or have been eating a lot of protein. If your creatinine and eGFR are normal, a mildly high urea is usually not a kidney problem. If creatinine is also high or eGFR is low, see your GP.
Common, everyday reasons:
Medical causes a doctor will look for:
A low urea usually reflects a low protein intake or a lot of fluid. In a healthy person, it is rarely a concern.
A low urea is worth a closer look when albumin or total protein are low too, or your liver function tests are abnormal.
Urea shifts easily, so preparation matters.
The urea:creatinine ratio compares these two waste products directly. A BUN:creatinine ratio on an overseas report is the US version, in different units.
| Pattern | What it can mean |
|---|---|
| High urea, normal creatinine and eGFR | Most often dehydration, high protein intake or hard training. Rehydrate and retest if it persists. |
| High urea with a high urea:creatinine ratio | Urea is outpacing creatinine, usually from fluid or protein, less often from bleeding in the upper gut. |
| High urea, high creatinine and low eGFR | Both waste products are building up together, which suggests reduced kidney filtering. Needs GP review. |
| Low urea with low albumin or total protein | May point to low protein intake or, less often, a liver problem. Worth reviewing. |
| High urea with abnormal sodium or potassium | Fluid or electrolyte balance may be off. Needs GP review if it doesn't settle. |
Most changes in urea come down to fluid and protein, and you can adjust both. If your kidneys are the reason, the focus shifts to protecting kidney function with your GP.
See your GP if your urea is above your lab's range together with a high creatinine or low eGFR, if it stays high on a repeat test after you've been well hydrated, or if it keeps rising over time. A very high urea, around 20 mmol/L or more, needs prompt medical attention.
Also see your GP for swollen ankles or legs, passing much less urine than usual, ongoing nausea, unusual tiredness, itchy skin or breathlessness. Black, tarry stools or vomiting blood need same-day care.
Urea sits in the kidney section of Vively's Baseline Health Check, next to creatinine, eGFR and your electrolytes. Your final marker list is confirmed when the referring doctor reviews your request.
Sign up online and our GP network arranges your referral. One blood draw at any of 3,700+ accredited partner collection centres, and results reach the app usually within a few days, set against optimal ranges in plain English. A Vively practitioner talks you through them and builds your personalised plan, and a retest shows whether changes to fluid or protein have moved the number. If your urea is a bit high because you were short on water, we'll tell you that.
Check your urea and kidney markers with the Baseline Health Check.
No. Urea can be tested after eating, though a large protein-heavy meal shortly before can nudge it up. Your Vively Baseline needs an overnight fast for glucose and insulin anyway, which takes care of that. Keep drinking water while you fast, because dehydration is the most common reason for a mildly high urea.
Yes, slightly. It is above many labs' upper limit of about 7.8 mmol/L, though some labs, especially for older adults, accept up to about 10 mmol/L. If your creatinine and eGFR are normal, dehydration or a high protein intake is the likely cause. Rehydrate and retest, and see your GP if it stays high.
Yes. When you're low on fluid, your kidneys hold onto water and reabsorb more urea along with it, so the blood level rises. Urea usually rises proportionally more than creatinine, which pushes the urea:creatinine ratio up. A repeat test after a normal, well-hydrated day usually brings it back down.
Yes. The more protein you eat, the more urea your liver makes, so high-protein diets and regular protein shakes can push urea towards or above the top of the range. With normal creatinine and eGFR this isn't kidney damage, but it's worth matching your intake to what your body needs.
They measure the same waste product in different ways. Australian labs report urea in mmol/L. US labs report blood urea nitrogen (BUN) in mg/dL, which counts only the nitrogen in urea. Multiply BUN by 0.357 to get urea in mmol/L, so a BUN of 14 mg/dL is about 5 mmol/L.
Yes, it can be. Many blood tests, urea included, can be Medicare-funded when a doctor orders them for a clinical reason. With Vively, we arrange the referral through our GP network, and urea is requested with your other kidney markers as part of the Baseline Health Check.
Among 6,029 Vively members tested in 2024 to 2026, women aged 40 to 49 had a median urea of 4.9 mmol/L (middle half 4.2 to 5.8). Men the same age: 6.1 mmol/L. The lab range is 2.3 to 10.0 mmol/L. A member median is not a target.
The line is the median member at each age. The shaded bands show where most members sit. The dashed red lines are the lab range.
| Group (mmol/L) | Members | Median | Middle 50% | 5th to 95th percentile | Lab range |
|---|---|---|---|---|---|
| Women 18 to 29 | 263 | 4.6 | 3.9 to 5.4 | 3.0 to 6.7 | 2.3 to 10.0 |
| Women 30 to 39 | 982 | 4.8 | 4.0 to 5.6 | 3.1 to 7.1 | 2.3 to 10.0 |
| Women 40 to 49 | 1,149 | 4.9 | 4.2 to 5.8 | 3.1 to 7.4 | 2.3 to 10.0 |
| Women 50 to 59 | 858 | 5.4 | 4.5 to 6.3 | 3.4 to 7.9 | 2.3 to 10.0 |
| Women 60 and over | 492 | 5.6 | 4.7 to 6.5 | 3.6 to 8.2 | 2.3 to 10.0 |
| Men 18 to 29 | 265 | 6.1 | 5.1 to 7.2 | 3.8 to 9.0 | 2.3 to 10.0 |
| Men 30 to 39 | 647 | 6.1 | 5.1 to 7.0 | 3.9 to 8.6 | 2.3 to 10.0 |
| Men 40 to 49 | 699 | 6.1 | 5.1 to 7.1 | 4.0 to 8.6 | 2.3 to 10.0 |
| Men 50 to 59 | 410 | 6.1 | 5.3 to 7.2 | 4.2 to 8.9 | 2.3 to 10.0 |
| Men 60 and over | 264 | 6.5 | 5.3 to 7.6 | 4.4 to 10.7 | 2.3 to 10.0 |
Pick your sex and age, then type your result.
What is a normal urea level for my age?
Among 6,029 Vively members (first blood test, January 2024 to October 2026), the median urea for women was 4.6 mmol/L at 18 to 29, 4.8 at 30 to 39, 4.9 at 40 to 49, 5.4 at 50 to 59 and 5.6 at 60 and over. For men it was 6.1 mmol/L at 18 to 29, 6.1 at 30 to 39, 6.1 at 40 to 49, 6.1 at 50 to 59 and 6.5 at 60 and over.
The lab range is 2.3 to 10.0 mmol/L. A member median is not a target or a diagnosis. If your result is outside the range on your report, talk to your GP.
How to get it: Included in the Baseline Health Check. A GP from our network signs your request after a short telehealth consult, so you don't need to visit your own GP first. See how a blood test without a referral works.
Related tests: Anion Gap, Bicarbonate, Urea/Creatinine Ratio, Sodium/Potassium Ratio
The Baseline Health Check reads 70+ markers, then your dietitian turns your results into a plan. $99 a month, first test included.
Every marker in range? Get your $99 back. T&Cs apply.