Uric Acid Examination Procedure

1.Purpose of examination: Uric acid estimation from serum or plasma by Uricase Method.

2.Responsibility and Authority:

• Calibration: Technician
• Quality Control: Technician
• Routine operation: Technician
• Overall Monitoring: Quality Manager

3.Sample Details:

1. Type of Sample: Serum, Plasma
2. Type of container and additives: Plain without any additives
3. Patient Preparation: As per Primary Sample Collection Manual sample_collection_manual
4. Stability: At Room temperature 18°–28°C (64°–82°F) stability ≤ 24 hours
5. Handling and transport: As per Primary Sample collection manual
6. Storage: 24 hours at 2-8° C

4.Required Equipment: Centrifuge, Auto-Pipette, Disposable Tips, Disposable sample cups, FullyAuto Chemistry Analyzer

5.Required reagents: R1 TODB (0.847 g/L). R2 4-aminoantipyrine (0.285 g/L), TODB (0.847 g/L). peroxidase (POD) (4.000 KU/L), uricase (2.000 KU/L).

6.Reagent Handling

• Remove any air bubbles present in the reagents with a new applicator stick, or allow the reagents to settle at the appropriate storage temperature to allow the bubbles to dissipate. To minimize volume depletion, do not use a transfer pipette to remove bubbles

7.Reagent Storage and stability

• Unopened reagent stable at 2-8°C until expiration date.
• On board System temperature reagent is stable for 30 days
• Instability or deterioration should be suspected if there are precipitates, visible signs of leakage or
• contamination, turbidity, or if calibration or controls do not meet the appropriate criteria.

8.Calibration Procedure: Consolidated Chemistry Calibrator Frequency:

1. Reagent lot change
2. QC out of range
3. After service or maintenance
4. Replacement in any parts of Instrument

Procedure:

1. Start the equipment.WDI abbotte fully.docx
2. Calibrators are ready to use.
3. Put calibrator 15-20 minutes at room temperature
4. Prior to use, mix the contents by inverting the vial. Do not shake the vial to prevent foam formation.
5. Take a 150 µl calibrator solution inseparate aliquot.
6. Go to the calibration and give the calibration order.
7. Verify calibration with at least two levels of controls
8. If control results fall outside acceptable ranges,root cause analysis or recalibration may be necessary.

9.Quality control Procedure:

• Name: Bio Rad Level 1 & 2
• Frequency: As per Quality Control Procedure

10.Procedure for Reconstitution of IQC

1. Reconstitution of QC material with 5 ml Distilled water by using calibrated fixed volume pipette.
2. Leave to stand for 30 min in the dark place.
3. Swirl gently several times during the reconstitution period to ensure that the contents are completely dissolved.
4. Prior to use, mix the contents by inverting the vial. Do not shake the vial as the information of foam should be avoided. Ensure that no lyophilized material remains un-reconstituted.
5. Prepare aliquots of 150 µl from the reconstituted QC material.
6. Store these aliquots at -15° C to -20° C.
7. Prior to use, make sure that aliquots should be at room temperature for at least 15 min.

Procedure to run IQC

1. Press Control order
2. Select Assay /Panel, to be run.
3. Select the control/s and its level/s
4. Give Carrier Number and Position number
5. Press F3 / Add order
6. Put respected carrier in RSH rack
7. Check IQC results, in case outliers call residents.

11.Principle of the procedure used for examinations:

• Uric acid is oxidized to allantoin by uricase with the production of hydrogen peroxide (H2O2).The H2O2 reacts with 4-aminoantipyrine (4-AAP) and N, N-bis-(4-sulfobutyl)-3-methylaniline, disodium salt (TODB) in the presence of peroxidase (POD) to yield a quinoneimine dye. The resulting change in absorbance at 604 nm is proportional to the uric acid concentration in the sample.

12.Sample Preparation:

• Required SampleVolume: 150 µl of the sample
• Temperature: 37°

Take 150-200µl of the sample from Primary tube to the secondary aliquot. Write the sample ID on the aliquot.

Procedure to run Patient sample

• Press Patient order
• Select Assay /Panel, to be run.
• Give Carrier Number and Position number
• Press F3 / Add order
• Put respected carrier in RSH rack

13.Performance Characteristics: Linearity: of 0.3 to 37.7 mg/dL

Automated Dilution Protocol: When using the Automated Dilution Protocol, the system performs a dilution of the specimen and automatically corrects the concentration by multiplying the result by the appropriate dilution factor. Manual Dilution Procedure: Dilute the specimen with saline (0.85% to 0.90% NaCl). Enter the dilution factor in the Patient or Control order screen

• The limit of detection (LOD): 0.2 mg/dL
• The limit of quantification(LOQ): 0.3 mg/dL
• Unit: mg/dL

Normal and critical ranges:

Uric acid

14.Laboratory Clinical interpretation: The Uric Acid 2 assay is to be used as an aid in the diagnosis and treatment of numerous renal and metabolic disorders, including renal failure, gout, leukemia, psoriasis, starvation or other wasting conditions, and of patients receiving cytotoxic drugs. Decreased levels are present in patients with Wilson’s disease.

15.Interference and cross reaction: The Following analytes were tested up to the two levels indicated at Uric Acid concentrations of (approximately 4 mg/dL and 7 mg/dL). and found not to interfere: Interfering Substance

• No interference from Bilirubin up to 40 mg/dl
• No interference from Hemoglobin up to 2000 mg/dL
• No interference from Intralipid up to 750 mg/dL
• No interference from Ascorbic acid up to 30 mg/dl
• No interference from Glucose up to 1000 mg/dl
• Potential source of variation:

Turn around time (TAT):

• Routine: 6.0 hours
• Urgent:r2.0 hours

16.Recording of observation:

• Software backup
• Machine raw data

17.Storage & Disposal of waste: Follow storage & discard procedure

18.Environmental & Safety control: Reagent R1 contains methylchloroisothiazolone and boric acid that causes allergic skin reaction,and damafe fertility or unborn child.

19.Precautions:

• Wear protective gloves / protective clothing / eye protection
• Do not breathe mist / vapors / spray
• Wash hands thoroughly after handling
• Keep only in original container

Response

IF SWALLOWED: Rinse mouth. Do NOT induce vomiting IF IN EYES: * Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do.

• Continue rinsing

IF ON SKIN (or hair):

• Take off immediately all contaminated clothing. Rinse skin with water / shower.
• Immediately call a POISON CENTER or doctor / physician.
• Absorb spillage to prevent material damage

For Reagent R2:

• Explosive when dry
• Picric acid is a flammable solid when wet as a paste (i.e., not less than 10% water), and explosive when dry.
• Prevent from forming crystals.
• Keep containers tightly sealed.
• Do not allow it to dry out.

20.References:

1. World health organization. Biosafety manual,3rd edition.
2. Burtis CA,Ashwood ER,editors,Tietz Textbook of clinical chemistry
3. Kaplan LA,Pesce AJ editors. Clinical Chemistry Theory, Analysis, and Correlation, 3rd ed.