Are Urea and Urine the Same Thing?

urea
Urea and urine are different because urea is a nitrogen-containing waste substance that excretes into the urine.

No, both urea and urine are different.

In humans, urea is a nitrogen-containing waste substance that the kidneys clear from the blood and excrete into the urine. Human urine consists of water, urea, inorganic salts, creatinine, ammonia, and pigmented products.

Amino acids are derived from protein breakdown to form ammonia. The liver enzymes convert ammonia into urea. Urea is then filtered by the kidney in the urine and excreted.

What does an abnormal urea level in the urine indicate?

The ideal urea level should be 12 to 20 grams over 24 hours in the urine. A healthy, adult human’s blood should contain 6 to 20 mg/dL (2.1 to 7.1 mmol/L) of urea (blood urea nitrogen or BUN).

A higher level of urea in the urine may be caused by the following reasons:

  • High-protein diet
  • Excessive protein degradation in the body
  • Kidney damage
  • Heart failure
  • Diabetes
  • Shock
  • Burn injuries
  • Stress
  • Gastrointestinal bleeding
  • Urinary tract obstruction

A lower urea level may be caused by the following reasons:

How can you identify abnormal urea levels in your urine?

If urea is not removed by the kidney, it can increase the urea level in the body, leading to a condition called uremia.

Higher urea levels can cause the following symptoms:

Low urea levels are not common and are not generally a cause for concern. They are usually observed in severe liver disease or malnutrition.

What tests can determine the urea level in the urine?

One test to identify urea levels includes a urine urea nitrogen test. In this test, urine samples are collected to evaluate the urea level.

Blood urea nitrogen (BUN) is the most common test that can determine the amount of urea in the blood. It reveals any issues with the kidney as well. The doctor may order a BUN as a part of the routine check-up or if a person presents with complaints indicating kidney disease.

The symptoms for which a BUN test may be ordered include:

  • Nausea or vomiting
  • High blood pressure
  • Swelling around the eyes or on the face, belly, arms, legs, or feet
  • Bloody, foamy, or coffee-colored urine
  • Frequent urination or low urine output

The purpose of a blood urea nitrogen test could be to:

  • Assess the functioning of the kidney.
  • Monitor a kidney disease.
  • Determine any kidney disorders.
  • Help diagnose several diseases and disorders affecting the kidney.
  • Determine the effectiveness of dialysis treatment.

Techniques involved in a BUN test procedure

A lab technician will take a blood sample from the vein in the arm or the back of the hand and send it for further analysis. The results will be available in a few days.

A person might feel slight pain and discomfort at the injection site for a few hours.

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References
Image Source: iStock Images

WebMD. What Is a Blood Urea Nitrogen Test? https://www.webmd.com/a-to-z-guides/blood-urea-nitrogen-test

University of Rochester Medical Center. Urea Nitrogen Clearance (Urine). https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=167&ContentID=urea_nitrogen_urine

Medline Plus. Urine and Urination. https://medlineplus.gov/urineandurination.html

Cleveland Clinic. Blood Urea Nitrogen (BUN) Test. https://my.clevelandclinic.org/health/diagnostics/17684-blood-urea-nitrogen-bun-test