Home › Biomarkers › Urea/creatinine ratio
According to MedlinePlus, being over 60 is one of the reasons you are more likely to have a problem with your kidneys. At first, such a problem often causes no symptoms.[1]
On this page you can read what the urea/creatinine ratio is, what the guidelines say about a value that is too low or too high, what affects your value and which values are best to look at alongside it.
Also known as: BUN/creatinine ratio, urea-creatinine ratio. At the lab: n/a.
Urea, or more precisely urea nitrogen, is a waste product. It forms when your body breaks down protein. Your blood carries it to your kidneys, which remove it in your urine.[1]
Creatinine is also a waste product. It is made when you use your muscles and some of the muscle tissue breaks down. Your kidneys filter it out of your blood and remove it in your urine.[2]
The urea/creatinine ratio puts those two side by side. MedlinePlus lists the BUN to Creatinine Ratio as another name for the urea test. The source also says that creatinine and urea from the same blood test can be compared with each other.[1, 2]
A problem with your kidneys often causes no symptoms at first. A urea test can reveal such a problem early.[1]
Creatinine alone does not tell the whole story. How much you make depends on your muscles, your diet, your age and how active you are. That is why it is often compared with other substances, such as urea, to learn more.[2]
MedlinePlus lists a number of things that raise your chance of a kidney problem: high blood pressure, kidney problems in the family, smoking, obesity and being older than 50.[2]
| Result | Can point to | Who it is for |
|---|---|---|
| Urea higher than normal[1] | Kidneys that are not working as well | Everyone |
| Urea higher than normal[1] | Dehydration, burns, certain medicines or food high in protein | Everyone |
| Urea lower than normal[1] | Too little protein in your diet, malnutrition or a liver condition | Everyone |
| Normal value[1] | Differs from person to person | Differs by sex and usually rises with age |
Source: MedlinePlus (U.S. National Library of Medicine) on urea in blood, one of the two parts of the ratio. The source gives no limits in numbers.[1]
A high ratio means there is a lot of urea compared with creatinine. MedlinePlus gives no limit for the ratio itself. The source does say that urea and creatinine from the same blood test can be compared to find the cause of a kidney problem. A higher urea can point to kidneys that are not working as well, but also to dehydration, certain medicines or a lot of protein in your diet. Talk to your doctor about what your result means.[1, 2]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
Food high in protein can raise your urea. Too little protein can lower it. Meat can raise your creatinine for a while. That is why your doctor may sometimes ask you not to eat meat for 24 hours before the test.[1, 2]
Dehydration, meaning too little fluid in your body, can raise your urea.[1]
Some medicines can raise your urea. Medicines and supplements can also affect your creatinine result. Tell your doctor everything you take. Do not stop a medicine on your own unless your doctor tells you to.[1, 2]
How much creatinine you make depends on your muscles, your age and how active you are. Urea differs between the sexes and usually rises with age.[1, 2]
Urea/creatinine ratio is included in BioProfile 77, 87, 121 and 150.[3]
The BioProfile editorial team wrote this page on 17 October 2026 from the sources below, which we read on 17 October 2026. Every number on this page comes from one of those sources, with that source's number next to it. An expert has yet to check this page; once checked, the expert's name and the date of the check will appear at the top. This page explains and does not diagnose. Talk to your GP about a value that is out of range.
