Insight into your urea level.
Urea is a waste product of protein metabolism that is excreted by the kidneys. A test gives insight into the urea level in your blood, as part of the picture of your kidney function and fluid balance.
Also known as: urea
Interpreted by BIG-registered doctors
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Background
What is urea?
When the body breaks down proteins, nitrogen is released. The liver converts that nitrogen into urea, a soluble waste product. The urea enters the blood and is filtered out of the blood by the kidneys and excreted in the urine. The urea level in your blood therefore reflects the interplay between production in the liver and excretion by the kidneys.
Urea is strongly influenced by factors beyond kidney function. A protein-rich diet increases production, and dehydration raises the value because the kidneys then retain more water and urea. Urea on its own is therefore not a precise measure of kidney function. The value is almost always viewed together with creatinine and eGFR, which are more specific for the filtering capacity of the kidneys. It is precisely that combination that makes urea useful: the difference between urea and creatinine gives your doctor extra context, for example about your fluid balance.
In brief
Protein metabolism
Waste product from the breakdown of proteins
Through the kidneys
Filtered out and excreted in the urine
Fluid balance
Dehydration raises the value
Together with creatinine
Creatinine and eGFR are more specific for kidney function
Common reasons to test
When can insight into your Urea be valuable?
Below are some situations in which measuring Urea can provide insight.
Insight into your kidney function
A test gives a snapshot of the urea in your blood, as a complement to creatinine and eGFR.
Together with creatinine and eGFR
Creatinine and eGFR are more specific for filtering capacity. Together with urea they give a fuller picture of your kidneys.
With a protein-rich diet
Eating a lot of protein or using protein shakes increases urea production. A test then gives insight into your current value.
With questions about your fluid balance
Dehydration raises urea. The value gives your doctor context about your fluid balance at the moment of the draw.
With long-term medication use
Some medicines, such as diuretics and certain painkillers, put a strain on the kidneys. A test gives insight into your current values.
For periodic monitoring
Those tracking their kidney values periodically often use urea as a reference point alongside creatinine and eGFR.
What your result means
How do we read your Urea level?
Urea is measured in millimoles per litre (mmol/L). The laboratory states the reference values that apply there alongside your result. Important: urea is strongly influenced by your protein intake and your fluid balance. It is therefore not a precise measure of kidney function and is best assessed together with creatinine and eGFR.
A low value
A low urea level is usually harmless. It fits, for example, with a low-protein diet or with drinking a lot of fluids. Less often, reduced production in the liver plays a role. Our doctor provides explanation and context with your result.
A normal value
A urea level within the laboratory's reference values gives a reassuring picture for this marker at this moment. It remains a snapshot. Because urea is strongly influenced by diet and fluid balance, a normal value does not rule out reduced kidney function. Creatinine and eGFR give more specific insight into that.
An elevated value
An elevated urea level is often explained by not drinking enough or by a protein-rich diet. Certain medicines can also raise the value. In addition, an elevated value can fit with reduced kidney function, certainly if creatinine and eGFR are abnormal as well. A single measurement is not a diagnosis. Our doctor explains what your value means and whether a repeat test or follow-up via your GP is customary.
How we interpret your result
Our doctors interpret your urea level against the laboratory's reference values and your personal context, such as diet, fluid intake, lifestyle, medication use and any known conditions.
Related tests
Often combined with Urea.
A single marker gives one perspective. For a broader picture you can combine Urea with a theme package or related markers.
Frequently asked questions
Everything you want to know
Do I need to fast for a urea test?
No, you do not need to fast for a urea measurement. It is wise to drink normally before your draw, however, because dehydration raises the urea level.
What is the difference between urea and creatinine?
Both are waste products that the kidneys filter out of the blood. Creatinine comes from muscle metabolism and, together with eGFR, is more specific for the filtering capacity of the kidneys. Urea comes from protein metabolism and is strongly influenced by your diet and fluid balance. That is why they are preferably viewed together.
Does an elevated urea mean my kidneys are working less well?
Not necessarily. Not drinking enough and a protein-rich diet also raise urea in people with well-functioning kidneys. If creatinine and eGFR are abnormal as well, that is a stronger signal. Our doctor assesses the values in context and indicates whether follow-up is customary.
Do protein shakes affect my urea level?
Yes. A high protein intake, for example through protein shakes or a lot of meat, increases urea production and therefore your blood level. Mention during your intake that you use protein supplements, so our doctor can take this into account.
Does drinking affect the result?
Yes. When dehydrated, the kidneys retain more water and urea, which raises the value. So drink normally in the hours before your blood draw, unless you need to fast for another test. Drinking water is fine even when fasting.
Which medicines affect urea?
Diuretics, certain blood pressure medicines and long-term use of some painkillers can affect the kidney values. State your medication during the intake so our doctor can place your result in the right context.
How often should I have urea measured?
A single measurement is enough for initial insight, preferably together with creatinine and eGFR. If an earlier value was abnormal or you use medication that strains the kidneys long term, periodic re-testing is customary. Your doctor will advise on this.
What do I do with my result?
You receive a PDF report with your value and a personal explanation from our doctor. What you do with it, such as discussing it with your GP, remains entirely your choice.
Ready for insight into your urea level?
For €49 you receive your urea level including personal explanation from a doctor, typically within a few working days. No referral required.
Order Urea for €49 →Want to test multiple markers at once?
Combine Urea with other markers via Bloodworks Select. Blood draw costs are waived from €225.
49,-
All-in, blood draw included