Blood Urea / Urease
Definition:
Blood urea is the level of urea in the blood. Normal kidney function keeps the blood ureal levels low by excreting it in the urine. A high blood urea suggests kidney failure is called blood urea.
Principle of B.urea:
urea is a hydrolyzed enzyme urease to produces ammonia and carbon dioxide. The ammonium ions react with hypochlorite and salicylate to give green dye. The intensity of the color is measured by the colorimeter of the semi-auto analyzer.
Chemical Reaction: Urea + h20 = 2HN3 + CO2
NH3 + hypochlorite + salicylate = Green dye
Blood Urea or BUN
Indication of B.urea test:
1. Urinary tract infection (UTI)
2. Nephrotic Syndrome
3. Acute Glomerulonephritis
4. Metabolic and Systemic diseases:
* Diabetes Mellitus (DM)
* Diabetes Insipidus
* Jaundice
5. To detect calculi in the urinary tract
6. Kidney failure
7. Enlargement of kidney
8. Damage of Kidney
9. Acute renal failure
10. Chronic renal disease
11. Shock
12. Dehydration.
Doctor investigation of B.urea Test: B.urea, urea, urease, or BUN is results 2.14 divided into Urea.
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| Blood Urea |
Sample Collection: Venous blood
Specimen type: Heparinized Plasma, Serum,
Preferred collection container: Red tube vial or yellow jell vial.
Specimen Required: 2 ml of serum or plasma or a minimum of 0.5 ml
Special notes: Outreach clients: Specimen may also be collected in red vials. Place specimen on centrifuge and separate plasma from cells
Patient preparation: Random sample collection.
Specimen processing instructions: Plasma: Centrifuge at 1500-2000 rpm for a minimum of 10 minutes.
Serum: Allow to clot. Centrifuge at 1100-2000 rpm for a minimum of 10 minutes. For specimens collected in anything other than a red or yellow vial, the specimen is not acceptable for B.urea testing if not centrifuged within two hours of collection.
Transport temperature: Spun SST: Room temperature 8 hours; refrigerated 3 days.
Spun PST Room temperature for 4 hours; refrigerate for 8 hours.
Red or yellow top: 3 days (spun and unspun).
Methods of B.urea Estimation: Endpoint
Reagent Preparation: All reagents are ready for use.
Stability of working reagent: From 2-8 degrees Celsius temperature express date.
Reagents required:
* Reagent-1
* Reagent-2
* Reagent-3
* Standard solution
Concentration Of standard: 80 mg/dl
Analyzer Parameter:
Wavelength / Filter: 580 nm
Method: End Point
Cuvette : 1cm light path
Reaction Direction: 30 minutes
Bank: Distilled Water
Reagent Volume: 1000 microliters
Sample Volume (ul): 10 microliters
Normal Low (mg/dl) : 10
Normal High (mg/dl) : 50
Linearity Low (mg/dl): 2.0
Linearity High (mg/dl): 400
Units: mg/dl
Test Procedure:
Blank Standard Sample
Reagent 1 1 ml 1ml 1ml
Reagent 3 10 microliter 10 microliter 10 microliter
Standard - 10 microliter -
Sample - - 10 microliter
Mixed incubated for 10 minutes at room temperature or 5 minutes at 37 * c
Reagent 2 1ml 1ml 1ml
Mix well and incubate for 10 minutes at room temperature or 5 minutes at 37 * c then read the absorbance (OD) of the sample and standard against the reagent blank
Calculation and curve:
Concentration of sample = OD of Test/OD of standard * concentration of standard (80 mg/dl)
Normal Value: 10-50 mg / dl or 15-45 mg/dl
BUN: Dividing blood urea by 2.14 gives the results of BUN.
Materials:
- Cotton
- Hexaso
- Tourniquet
- Gloves
- Marker Pen
- Test tube rack
- Disposable Syringe
- Gel tube / Yellow vial
- Stop Watch
- Calculator
- Colorimeter
- Semi-Auto analyzer
- Incubator
- Micropipette
Linearity:
Linearity in the context of a blood urea test refers to the ability of the test to provide accurate and consistent results across a range of concentrations of blood urea nitrogen (BUN). Linearity testing is important to ensure that the test remains reliable when measuring both high and low levels of BUN. In medical diagnostics, linearity is a critical aspect of assay validation, ensuring that the test results are proportional to the actual concentrations of the analyte being measured.
Here's how linearity is typically assessed in a blood urea test:
1. Calibration: To evaluate linearity, a laboratory will calibrate its equipment and assays using a set of standard reference materials with known concentrations of BUN. These reference materials cover a range of concentrations, from low to high, that are relevant to the clinical use of the test.
2.Testing Range: The linearity of the blood urea test is assessed within its specified testing range. This range is typically determined by the assay's calibration and may vary depending on the specific testing method and equipment used.
3. Dilutions: Linearity is evaluated by preparing a series of dilutions of patient samples with known BUN concentrations. These dilutions cover the lower and upper ends of the testing range. The laboratory then measures the BUN levels in these diluted samples using the same test method that is used for patient samples.
4. Comparison: The measured results of the diluted samples are compared to the expected results based on the dilution factor. The degree to which the measured results align with the expected results helps assess the linearity of the test. Ideally, the measured results should be proportional to the dilution factor and fall within an acceptable margin of error.
5. Adjustments: If linearity is not within acceptable limits, adjustments may need to be made to the test method or equipment to improve the accuracy and linearity of results across the entire testing range.
Maintaining linearity is crucial for the clinical utility of a blood urea test because it ensures that healthcare providers can rely on the test results to accurately reflect the patient's BUN levels, whether they are within the normal range or significantly elevated. Accurate results are essential for diagnosing and monitoring kidney function, as well as for making informed clinical decisions regarding patient care.
Laboratories performing blood urea tests must follow established protocols and quality control measures to ensure the test's linearity, accuracy, and overall reliability. Regular calibration and validation of equipment and methods are essential components of this process.
Caution:
Blood Urea is an important test be care must be taken when testing blood sugar to avoid hemorrhagic blood you have to do QC every day as well as run standard
Reagent company name:
1 .TRADSWORTH LTD (Human GmbH, Germany)
2. GENETIC TRADING
3. MEDI-VISION LTD
4. BIO-TRADE INTERNATIONAL
5. BIO-MEDICAL LIMITED
6. MEDITECH
7. HEALTH CARE TECHNOLOGIES
8. RAJANIGANDHA INTERNATIONAL
9. RANDOX
10.PLASMATEX
11. LEIZ SUPPLY AGENCY
12. ABC INTERNATIONAL
13. ROSE INTERNATIONAL
14. BIOZEN.
