URIC ACID 10.001.00 INTENDED USE TECHNICAL PROCEDURE
Kit intended to determination of uric acid in serum, urine and synovial fluid.
A) REAGENT PREPARATION PRINCIPLE OF THE METHOD
The uric acid from sample in presence of uricase and dioxygen produces allantoin
OBS 1: The absorbance of the reagent above 0,150 at 500 nm, with the
and hydrogen peroxide. The hydrogen peroxide, in presence of 3,5-Dichloro-2-
instrument adjusted to zero with distilled or deionized water, indicate deterioration.
hydroxy-benzenesulphonate (DHBS) and 4-aminoantipyrine,
Peroxidase producing a pink compound (Quinonimine) that absorbs the light at
OBS 2: Due to the volatility of isopropilic alcohol contained in standard the bottle
Uric Acid + O2 + 2 H2O uricase Allantoin + CO2 + H2O2
B) PROCEDURE
2 H2O2 + 4-aminoantipyrine + DHBS peroxidase Quinonimine + 3 H2O
Standard REAGENT COMPOSITION
Phosphate buffer 50 mmol/L pH 7.5; Uricase > 450 U/L.; Peroxidase
> 2500 U/L; 4-aminoantipyrine 0.3 mmol/L; DHBS 0.34 mmol/L.
2. Homogenize and incubate 10 minutes at 37 ºC.
Isopropilic alcohol 10% v/v, sodium azide 0,09% w/v; uric
3. Measure the absorbance of Standard (Ast) and Sample (Asa) against the blank at 505 nm (490-510 nm). The final reaction is stable for 15 minutes.
acid (the concentration is stated on the label).
CALIBRATION/CALCULATION PROCEDURES
The concentration of this standard was determined using the NIST 913a
Calculations of serum and synovial fluid STORAGE AND STABILITY •
Uric Acid (mg/dL) = Sample Absorbance x STD Concentration (mg/dL)
The reagents are stable up to the date stated on the label.
• Do not use reagents over the expiration date.
• Do not freeze and protect from light.
ADDITIONAL EQUIPMENT
Spectrophotometer or photometer able to read at 505 nm (490 - 510).
Uric Acid (mg/dL) = 0.175 x 10 = 12.7 mg/dL
With Calibration Factor (CF): WARNINGS AND PRECAUTIONS
The kit is intended for in vitro diagnostic use only.
Uric Acid (mg/dL) = Sample Absorbance x CF
All specimens and controls should be handled as potentially infective.
Wear the individual protection equipment accordingly to Good Laboratory
Discard the reactions surplus according to Good Laboratory Practice in a
proper place for potentially infective material.
Uric Acid (mg/dL) = 0.175 x 72.5 = 12.7 mg/dL
The information for Disposing, Security and First Aid are described in the
Manual Safety Data Sheet (MSDS) of this product available at
Calculations of Urine:
www.biotecnica.ind.br or calling for 55-35-3214-4646.
Urine (mg/24 hours) = *mg/dL x urinary volume (in mL)
Do not combine reagents from different batches.
Do not exchange the caps from different reagents in order to avoid cross
SENSITIVITY AND LINEARITY
Do not use the reagent if it displays any sign of contamination.
The reagents must be kept out of specified temperatures only the time
necessary for the realization of the tests.
Use glass pipettes and disposable tips for each sample, control,
The level of water in the thermostatic bath must be over the level of mix
For values higher than 20 mg/dL, dilute the sample with NaCl (0.9%) solution,
repeat the assay and multiply the obtained result by the dilution factor.
SAMPLE – PREPARATION AND STABILITY TECHNICAL LIMITATIONS
The anticoagulants may interfere in the reaction. The fluoride ion inhibits the
Serum: Separate the cells up to two hours after collection.
For Lipemic or elevated Bilirubin (>10 mg/dL) sera mix 1 mL of 0.9% NaCl
• Hemolyzed, Jaundice and Lipemic Sera
solution with 0.02 mL of sample. Adjust the instrument to zero with
distilled or deionized water and read the absorbance at 505 nm.
Diminishes this absorbance from test absorbance before the
The uric acid in serum is stable for 3 days at 2 to 8 °C.
• Urine: Work with samples collected in the period of 24 hours. Do not add
Acetozolamide, clorotiazide, furosemide, metildopa, fenotiazide,
- Homogenize the urine, measure the volume and separate a 20 mL
Vitamin C, acetohexamide, alopurinol, azatiopin, probemicide,
- Adjust the pH between 7 and 9 with 5% NaOH solution and heat the
mercaptopurine, coumarin, estrogens, sulfinpirazone, etc.
sample for 10 minutes at 56 ºC. This procedure dissolves the uric acid
QUALITY CONTROL
Any clinical laboratory must keep an internal quality control program, which
- Centrifuge the sample for 10 minutes at 3,000 rpm.
defines the aids, procedures and criteria for the tolerance limits, corrective actions
- Dilute a small part of the centrifuged urine in a 1:20 proportion with
and registration of the activities. Also, it must be kept a defined system for
verification of the analytical variability that occurs in any measuring system.
- Use the diluted urine to proceed with the assay.
The use of controls to evaluate the imprecision of the analysis must be a routine
practice in the lab. It’s suggested to use a control within the reference range and
other control within the clinical significance range. The application of the Multiple
The uric acid in urine (with NaHCO3) is stable for 4 days at 2 to 8 ºC.
Rules of Westgard for evaluation of the control state is recommended.
The lab must participate of external quality control programs.
For the internal quality control of the lab it’s indicated the use of the calibrator
- Centrifuge form 10 minutes at 3,000 rpm.
- Use the supernatant to execute the assay.
The uric acid in synovial fluid is stable for 5 days at 2 to 8 °C.
Pathological Control Serum – QuantiAlt
BIOTÉCNICA IND.COM. LTDA. Rua Ignácio Alvarenga nº 96, Vila Verônica,
Varginha MG BRASIL CEP: 37026-470 Tel/fax: +55 35 3214 4646
REFERENCE RANGES TABLE OF INTERNATIONAL SYMBOLS LANGUAGE EXPLANATION
These values are intended for orientation only. It’s recommended that each lab
Conversion for International System of Units (SI): mmol/L
For in vitro diagnostic medical device
PERFORMANCE CHARACTERISTICS Intra-Assay
The realization of 20 determinations of the same sample at the same day showed
Conteúdo suficiente para <n> testes
Inter-Assay
Contenido suficiente para <n> ensayos
The realization of 10 determinations of the same sample at different days showed
Analytical Specificity
A comparison with a reference method showed a correlation coefficient (r) of
0.980 obtained from ambulatory samples. The result equation of the linear
CLINICAL SIGNIFICANCE
Blood: the uric acid is the final product of the purine metabolism and is elevated in
several clinical situations besides the gout. Only 10% of the patients with
hiperuricemia have gout. High levels of uric acid are found in alcoholism, diabetic
ketoacidosis, psoriasis, pre-eclampsia, rich purine diet, neoplasics, post-
chemotherapy and radiotherapy and in the use of the medicines: paracetamol,
ampicilin, aspirin, diuretics, beta-blockers, etc.
Low levels of uric acid are found in poor purine diet, kidney tubular defects,
Data limite de utilização (último dia do mês)
porphyry and in the use of the medicines: tetracycline, alopurinol, aspirin,
corticoids, indometacin, metotrexate, methyldopa, verapamyl, heavy metal
intoxication and with increasing kidney “clearance”.
Urine: the kidneys eliminate approximately 70% of the uric acid. This
determination is then useful in patients with kidney stones. The alcohol causes
the lowering of urinary uric acid. Anti-inflammatory medicines, Vitamin C, diuretics
and warfarim may interfere with the results.
Synovial Fluid: may be useful in the differential diagnostics of arthropathies.
OBSERVATIONS
1. The cleaning and drying of the lab material are fundamental factors for the
stability of the reagents to reach correct results.
The water used in cleaning must be recent and free of contaminating agents. The
cleaning of the glassware must be done with neutral detergent. The rinsing must
be exhaustive being the last ones with distilled or deionised water.
2. The water used in the lab must have the specified quality for each application.
Thus, to prepare reagents the water must be of Type II, with resistivity > 1
megaohms/cm or conductivity < 1 microsiemens and silicate concentration < 0.1
mg/L. For the initial rinsing of the glassware, the water may be of Type III, with
resistivity > 0.1 megaohms/cm or conductivity < 10 microsiemens. In the final
rinse, the water must be of Type II. Saturated deionising columns releases
alkaline water, several ions and oxidizing or reducing agents that deteriorate the
reagents in a few days or even hours, changing the results in an unpredictable
way. Finally, it’s imperative to establish a program for the quality control of the water.
PRESENTATIONS QUALITY ASSURANCE Before being approved for use BioTécnica reagents are tested in the Quality Control Department. The quality of the reagents is assured up to the expiring date stated in the label of the external packaging, since it is stored and transported in the specified conditions. The quality control data concerning this product are available at www.biotecnicaltda.ind.br AUTOMATION This product is compatible to the most types of biochemical automatic analysers. The applications are available at www.biotecnicaltda.ind.br CUSTOMER TECHNICAL SERVICE Any technical doubt on handling this product or this procedure, contact us calling +55 35 3214 4646, your local distributor or sending an e-mail: [email protected] REFERENCES •
Barham D, Trinder P. Analyst 1972; 27:142-145.
Fossati P., Prencipe L., Bert G. Clim Chem 1980; 26: 227-231.
Pagana K.D.: Mosby’s diagnostic and laboratory test reference 1992, 754-758.
Guyton, Fisiologia humana e Mecanismos das doenças 1993, 5ª edição.
Westgard J. O., Barry P. L., Hunt M.R., Groth T. A multi-rule Shewhart chart quality control in clinical chemistry. Clin. Chem., 27:493-501,1981.
TECHNICAL RESPONSIBILITY Dr. Gilson Sério Pizzo - CRF MG – 5310 ANVISA REGISTRATION NUMBER 80027310038
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