BUN vs Urea: Difference and Comparison

Diagnosing and screening the organs is a common practice in medical science to detect severe diseases and medical conditions.

BUN and Urea are two interrelated terms measure urea nitrogen and urea volume in the blood. Both of these screenings use different parameters and have various symptoms, respectively.

Key Takeaways

1. Bun is a blood test that measures blood urea nitrogen level, while urea is a waste product of protein metabolism in the body.
2. High bun levels may indicate kidney dysfunction, while high urea levels may indicate liver dysfunction.
3. Bun is measured in milligrams per deciliter, while urea is measured in millimoles per liter.

BUN vs Urea

BUN stands for Blood Urea Nitrogen, a test measuring the amount of urea nitrogen in the blood. Urea is a waste product produced by the liver due to protein breakdown. It’s filtered out of the blood by the kidneys and excreted in the urine. It’s one of the substances measured in the BUN test.

BUN is a blood urea nitrogen test that detects whether the kidneys work well. Various processes and mechanisms occur in the human body, and protein breakdown is one of them.

The liver breakdown the food protein into various sub-components, and urea nitrogen is one of them. The body uses only a tiny amount of urea nitrogen, and the residue flushes out in urine.

Urea is a chemical compound produced in the blood and created by the liver.

Maintaining a constant level of Urea in the blood is essential because if the blood urea level increases, it may lead to severe medical consequences like heart failure, dehydration, uremic syndrome, or Uremia.

To lower the blood urea level, one should avoid smoking and alcohol or eat more fibre.

Comparison Table

Parameters of Comparison	BUN	Urea
What is it	Urea represents the total amount of the urea component present in the blood.	Change in urination, swelling in the legs or hands, feeling tired, Itching, fatigue, dehydration, vomiting, cramps, sleep disorder, and pale skin colour
Symptoms	High-level of BUN is not necessarily cause Uremia	Nausea, vomiting, fatigue, breath shortness, cramping, weight loss, altered taste, and sleepiness.
Measurement quantity	Blood urea nitrogen	Blood urea
Uremia	BUN represents nitrogen content in the Urea, and it should be between 7-21 mg/dL.	It does not include the kidney
Kidney involvement	BUN involve the kidney as it determines kidney dysfunction	It does not involve the kidney

What is BUN?

Routine health screening is essential to detect the effective functioning of the body’s organs. Body breakdown the food we eat into various sub-components.

Likewise, the liver breakdown the protein and produces urea nitrogen which further ends up in the kidneys.

Kidneys utilize a small amount of urea nitrogen in the blood while the residue flushes through urine.

If kidneys are not working well, then it is a bit difficult to remove the urea nitrogen from the blood, this increases the urea nitrogen level in the blood,

and hence the doctor suggests a BUN test to determine and measure the amount of urea nitrogen in the blood. The BUN test report decides whether the liver or kidney is working well.

Few symptoms help to identify if something is wrong with the kidneys. It can be a change in urination, swelling in the legs or hands, tiredness, Itching, fatigue, dehydration, vomiting, cramps, sleep disorder, and pale skin colour.

BUN level must be between 8 to 21 mg per dL. If anyone has more than 21 mg/dL of urea nitrogen in their blood, they must consult the doctor.

What is Urea?

Urea is a chemical compound in the blood and is formed by the liver during the breakdown of the food protein. Only a small amount of blood urea is used by the body while the remaining is flushing out through urine.

If urine level is high, it may lead to severe medical consequences like dehydration, Uremia, and heart failure.

The high urea level is the result of either the protein consumption being relatively high, or the kidneys are not capable of filtering the Urea from the blood.

Multiple symptoms help to determine high-level blood urea. It includes nausea, vomiting, fatigue, breath shortness, cramping, weight loss, altered taste, and sleepiness.

The doctor prescribes BUN and urea breath tests to measure the blood urea level.

Main Differences Between BUN and Urea

1. BUN and Urea are two different terms, but they are interrelated in one way or another. BUN is the blood urea nitrogen test that represents nitrogen content in the area, and the normal level of BUN should be between 7-21 mg/dL. On the contrary, Urea represents the total amount of the urea component in the blood.
2. Every medical condition has symptoms that make the person realize something is wrong with the body. BUN symptoms include a change in urination, swelling in the legs or hands, feeling tired, Itching, fatigue, dehydration, vomiting, cramps, sleep disorder, and pale skin colour. At the same time, the symptoms of Urea are Nausea, vomiting, fatigue, breath shortness, cramping, weight loss, altered taste, and sleepiness.
3. BUN and Urea represent two different components or quantities that are measured or determined, respectively. BUN determines the blood urea nitrogen while the area on the other side measures the total blood urea content.
4. Uremia is a medical condition that can occur because of kidney infection or injury and chronic disorder, and its symptoms are quite similar to that of BUN and Urea. An increase in blood urea will majorly lead to Uremia, but an increase in BUN level does not lead to Uremia.
5. The food we eat breakdown into sub-components. Similarly, the protein breakdown into components, and Urea is one of them. BUN involves the kidney as it determines kidney dysfunction, but Urea does not involve the kidneys.

References

1. https://www.ncbi.nlm.nih.gov/pmc/articles/pmc4149136/

Last Updated : 06 July, 2023