Know Your Blood Parameter: Urea
- Summarised by TGHC Editorial Team
- Jun 23, 2025
- 3 min read
Updated: Dec 22, 2025
Parameter Name
Urea
Urea is a nitrogenous compound that is formed in the liver as a result of protein metabolism. It is the primary component of urine and serves as a key indicator of renal function.
Test Type
Blood
The urea test is performed on a blood sample, which is typically drawn from a vein in the arm. This type of testing is crucial for evaluating how well the kidneys are filtering waste products from the blood.
Normal Range
10 – 40 mg/dL
This range may vary slightly depending on the laboratory and the methods used for testing. It is important to interpret the results in the context of the individual's overall health and other diagnostic tests.
High Levels Indicate
Kidney dysfunction, dehydration, heart failure, excessive protein breakdown.
Elevated urea levels can suggest that the kidneys are not functioning effectively, possibly due to conditions such as chronic kidney disease (CKD) or acute kidney injury. Dehydration can also concentrate urea in the blood, while heart failure may impair blood flow to the kidneys, leading to increased urea levels. Additionally, a high-protein diet or increased protein catabolism, as seen in certain illnesses, can elevate urea production.
Low Levels Indicate
Liver failure, malnutrition, overhydration.
Low urea levels may arise from liver dysfunction, where the liver is unable to produce adequate urea due to severe liver disease. Malnutrition, particularly protein deficiency, can also result in decreased urea production, as there are insufficient proteins to metabolize. Furthermore, excessive fluid intake can dilute blood urea concentrations, leading to lower measurements.
Why It's Tested
To assess nitrogen waste excretion by the kidneys.
This test is a vital component in evaluating kidney function and can help monitor the effectiveness of treatments for kidney-related conditions. By measuring urea levels, healthcare providers can gain insights into how well the kidneys are filtering waste and maintaining homeostasis in the body.
Associated Symptoms (if abnormal)
Nausea, confusion, fatigue, swelling (with high levels)
Abnormal urea levels can manifest in various ways. High levels may lead to symptoms such as nausea and confusion, which can be indicative of uremia, a condition resulting from the accumulation of waste products in the blood. Fatigue and swelling, particularly in the legs and abdomen, may also occur due to fluid retention and imbalances caused by kidney dysfunction.
What To Do If Abnormal
Evaluate with creatinine and BUN, review hydration and protein status.
In the case of abnormal urea levels, it is essential to conduct further evaluations, including tests for creatinine and blood urea nitrogen (BUN), to provide a more comprehensive assessment of kidney function. Additionally, reviewing the patient's hydration status and dietary protein intake can help determine potential causes of the abnormal results and guide appropriate management strategies.
Common Conditions Related
CKD, liver disease, high catabolic states
Several medical conditions can influence urea levels in the blood. Chronic kidney disease (CKD) is a primary concern, as it directly affects the kidneys' ability to filter waste efficiently. Liver diseases can also impact urea production, while states of high catabolism, such as those occurring in severe infections or trauma, can lead to increased protein breakdown and elevated urea levels.
Nutrition or Lifestyle Connection
Monitor protein intake, hydration; treat underlying liver/kidney issues.
Nutrition plays a significant role in managing urea levels. It is crucial to monitor dietary protein intake, as excessive protein can lead to increased urea production and potentially elevate blood levels. Additionally, maintaining proper hydration is essential to ensure optimal kidney function and waste excretion. Addressing any underlying liver or kidney issues through lifestyle modifications, dietary changes, and medical interventions can also help regulate urea levels effectively.
References (APA Format)
MedlinePlus. (2023). Urea test.
Mayo Clinic. (2022). Renal profile.
LabCorp. (2023). Kidney function testing.
