26. Urea Flashcards
What does Urea Consist of?
Approximately 50% is Nitrogen
What is Urea?
By-product of Protein Metabolism
By Liver
Removed from Blood, by Kidneys
What are the Characteristics of Urea?
NOT Toxic
Neutral
HIGHLY Water-Soluble
HENCE - Safe way to transport + excrete excess nitrogen
How Much Urea is Reabsorbed in the Renal Tubules?
40%
What is the Blood, Urea, Nitrogen Test (BUN)?
Measure of Amount of N2 in Blood
IN FORM of Urea
Measurement of Renal Function
What are the Analytical Methods of the BUN Test?
Colorimetric
Enzymatic Methods = HIGH Analytical Reliability
What are the Errors of the BUN Test?
Urease is SUPPRESSED by Heavy Metals
Interfered by
- Hemolysis
- Lipemia
- Endogenous NH3 + Drugs
What are the Indications of BUN Test?
Non-Clarified Comas
Post-Surgery Control
Patients on Haemodialysis
Chronic / Acute Renal Failure
Control of Food Protein Intake = Chronic Renal Failure
Is Urea an Adequate Indicator for Early Diagnosis of Renal Diseases?
NO
What Specimen are Required for the BUN Test?
Blood
Urine
Other Samples
When Must the Specimen should be Collected?
7 - 9 am in MORNING
What is Required of the Patient for the BUN Test?
NO Drugs
Physical + Psychological Rest BEFORE + DURING the Procedure
When is Blood Withdrawn in the BUN Test?
15 - 20 Minutes
AFTER SEATING
Hands MUST NOT Hang Down
What are the Reference Ranges of Urea Serum In MALE?
3.2 - 8.2 mmol / L
What are the Reference Ranges of Urea Serum In FEMALE?
2.6 - 7.2 mmol / L