John dempsey hospital

BAYER MULTISTIX® CLINITEK 50
URINE DIPSTICK PROCEDURE
DECENTRALIZED LABORATORY TESTING PROGRAM
I. CLINICAL
SIGNIFICANCE
The Bayer Diagnostic Reagent Strip for Urinalysis is a multi-parameter test strip used to measure certain constituents in the urine. These measurements are useful in the screening evaluation of renal, urinary, and metabolic disorders. Because of the simplicity of the technique involved, urine test strips rapidly provide evidence of pathologic change in the composition of urine. This routine testing of urine with test strips is the first step towards establishing a diagnosis that is then corroborated by clinical examination and more extensive laboratory analysis. II. PRINCIPLE
A brief discussion of each test principal follows. Specific Gravity: This test is based on the apparent pKa change of certain pretreated polyelectrolytes in
relation to ionic concentration. In the presence of an indicator, colors range from deep blue-green in urine of low ionic concentration through green and yellow-green in urines of increasing ionic Leukocytes: Granulocytic leukocytes contain esterases that catalyze the hydrolysis of the derivatized
pyrrole amino acid ester to liberate 3-hydroxy-5-phenyl pyrrole. This pyrrole then reacts with a diazonium Nitrite: This test depends upon the conversion of nitrate (derived from the diet) to nitrite by the action of
Gram negative bacteria in the urine. At the acid pH of the reagent area, nitrate in the urine reacts with p- arsanilic acid to form a diazonium compound. This diazonium compound in turn couples with 1,2,3,4- tetrahydrobenzo(h)quinolin-3-ol to produce a pink color. pH: The test is based on the double indicator principle that gives a broad range of colors covering the
entire urinary pH range. Colors range from orange through yellow and green to blue. Protein: This test based on the protein-error-of-indicators principle. At constant pH, the development of
any green color is due to the presence of protein. Colors range from yellow for “Negative” through yellow-green and green to green-blue for “Positive” reactions. Glucose: This test is based on a double sequential enzyme reaction. One enzyme, glucose oxidase,
catalyzes the formation of gluconic acid and hydrogen peroxide from the oxidation of glucose. A second enzyme, peroxidase, catalyzes the reaction of hydrogen peroxide with a potassium iodide chromogen to oxidize the chromogen to colors ranging from green to brown. Ketones: This test is based on the development of colors ranging from buff-pink, for a negative reading,
to purple when acetoacetic acid reacts with nitroprusside. Urobilinogen: This test is based on a modified Ehrlich reaction, in which p-diethlylaminobenzadehyde in
conjunction with a color enhancer reacts with urobilinogen in a strongly acid medium to produce a pink- Bilirubin: This test is based on the coupling of bilirubin with diazotized dichloroaniline in a strongly acid
medium. The color ranges through various shades of tan. Blood: This test is based on the peroxidase-like activity of hemoglobin, which catalyzes the reaction of
diisoproplybenzene dihydroperoxide and 3,3”,5,5”-tetramethylbenzidine. The resulting color ranges from orange through green; very high levels of blood may cause the color development to continue to blue. III. SPECIMEN
REQUIREMENTS
A. Patient Preparation: Specific patient preparation is not required. Bayer Multistix® urine test strips may be used on any freshly voided urine specimen. B. Specimen Collection and Handling: Collect urine in a clean container and test it as soon as possible. Do not centrifuge. The use of urine preservatives is not recommended. If testing cannot be performed within one hour after collection, the specimen should be refrigerated at 2 to 8°C immediately and returned to room temperature before testing. Mix the urine thoroughly before testing. Refrigerated specimens should be analyzed within four hours of collection. C. Specimen Stability: Nitrite test results are optimized by using a first morning specimen or one that has incubated in the bladder for four hours or more. It is especially important to use fresh urine to obtain optimal results with the test for bilirubin and urobilinogen, as these compounds are very unstable when exposed to room temperature and light. Prolonged exposure of urine to room temperature may result in microbial proliferation with resultant changes in pH. A shift to alkaline pH may cause false positive results with the protein test area. Urine containing glucose may decrease in pH as organisms metabolize the glucose. Bacterial growth from contaminating organisms may cause false positive blood reactions from the peroxidases produced. In random urine specimens from females, a positive result for leukocytes may be due to a source external Contamination of urine with skin cleansers containing chlorhexidine may affect protein (and to a lesser extent specific gravity and bilrubin) test results. D. Interfering Substances: Substances that cause abnormal urine color, such as drugs containing azo dyes (e.g., Pyridium®, Azo Ganstrisin®, Azo Gantanol®), nitrofurantoin (Macrodantin®, Furadantin®), and riboflavin, may affect the readability of the reagent areas on urinalysis reagent strips. The color development on the reagent pad may be masked, or a color reaction may be produced on the pad that could be interpreted visually and/or instrumentally as a false positive. REAGENTS AND MATERIALS REQUIRED
Materials required: MULTISTIX® 10 SG urine test strips, Quantimetrix Dipstick Control - The dropper plus™, CLINITEK® 50 urine chemistry analyzer and a clean specimen container. Listed are the Specific Gravity:
68.8% w/w poly (methly ether/maleic anhydride) Leukocytes:
0.4% w/w derivatized pyrrole amino acid ester Nitrite:
1.3% w/w 1,2,3,4-tetrahydrobenzol(h)-quinolin-3-ol Protein:
Glucose:
2.2% w/w glucose oxidase (microbial, 1.3 IU) 1.0% w/w peroxidase (horseradish, 3300 IU) Ketones:
Urobilinogen:
Bilirubin:
0.4% w/w 2,4-dichloroaniline diazonium salt 6.8% w/w diisopropylbenzene dihydroperoxide 4.0% w/w 3,3’,5,5’-tetramethylbenzidine STORAGE AND STABILITY
A. Store at room temperature between 15°-30°C (59°-86°C). Do not use the product after the expiration date. Do not store the bottle in direct sunlight. All unused test strips must remain in the original bottle. Transfer to any another container may cause reagent strips to deteriorate and become unreactive. Do not remove desiccant(s) from the bottle. Do not remove the strip from the bottle until immediately before it is to be used for testing. Replace the cap immediately and tightly after removing the B. Precautions: Universal precautions MUST always be followed whenever blood or body fluids are handled. These precautions include wearing gloves. Do not touch test areas of the reagent strip. Work areas should be free of detergents and other contaminating substances. VI. CALIBRATION
CLINITEK® 50 urine chemistry analyzer performs a “self-test” and calibration each time it is turned on. Each time a test is run, the instrument calibrates again, using the white plastic bar located on VII. QUALITY
Quality control procedure consists of following good laboratory techniques, ensuring that reagents are stored properly and specimens are handled according to instructions. To ensure accurate results, known controls are analyzed. To ensure proper technique and reactivity of the urine test strips, use two levels of quality control materials, Quantimetrix Dipstick Control - The dropper plus™. Quality control is performed for the following reasons: A. A new container of testing/product solution is opened. B. A new lot number of testing product/control solution is opened. C. The integrity of the testing product/control solution is questionable (ex. unusual color of a D. A questionable patient result is obtained. E. At minimum, a random vial is chosen and QC performed daily, or each day of use. The procedure for performing quality control is the same as performing a patient test. (See procedure below.) Be sure that quality control materials are at room temperature before analysis. All quality control VIII. PROCEDURE
Before proceeding, check expiration date of the reagent strips and quality control solutions. Do 1. Turn the analyzer ON. Testing can be started only from READY FOR TEST screen. Be sure Reagent Strip name on screen agrees with the strip being used. 2. Clean test strip table using a 70% isopropyl alcohol pad. Allow to air dry. 3. Remove a Reagent Strip from the bottle and replace cap. 4. Allow the Quanitmatrix urine dipstick control vials to come to room temperature, approximately 15 minutes. Gently invert the dropper vial 4-5x to mix contents. 5. Squeeze the dropper vial at the top of the reagent strip and allow the solution to drain down the reagent strip, making sure each test pad is completely saturated. To avoid contamination, do not touch the tip of the vial to the test strip. 6. Press the green start key and at the same time, blot the strip to remove excess liquid by touching the edge to a paper towel. Do not drag the strip across the paper towel. Hold the strip in a horizontal position to prevent possible mixing of chemicals from adjacent 7. Place the reagent strip, with the test pads facing up, into the middle trough of the test strip table. Slide the strip along the table until it touches the end of the trough. Note: You
must place the test strip while the message PLACE TEST ON TABLE is on the
screen. It will appear for 10 seconds.
8. The table is automatically pulled into the Analyzer. The instrument will read each reagent area at a specified time. Results are available in one minute. Be sure not to 9. Remove the used Reagent Strip and discard it in the proper container. 10. Wipe the test strip table with a damp, lint-free tissue. This should be done after 11. Label the printout with the quality control material that was tested and affix it to the Decentralized Laboratory Testing Quality Control Log. Verify each analyte is within the acceptable "Assayed Value” range, troubleshoot if necessary. Repeat for the other level Properly identify the patient or patient specimen before any testing procedure.
1. Turn the analyzer ON. Testing can be started only from READY FOR TEST screen. Be sure Reagent Strip name on screen agrees with the strip being used. 2. Mix the urine by gently swirling the container. If the urine depth is less than 3 inches, 3. Remove one Reagent Strip from the bottle and replace cap. 4. Dip the reagent strip into the urine. Be sure all of the test pads are saturated. 5. Immediately remove the reagent strip from the urine, dragging the edge of the strip against the side of the container as you remove the strip. At the same time, press the
green start key. Hold the strip in a horizontal position to prevent possible mixing of 6. Blot the strip to remove excess liquid by touching the edge to a paper towel. Do not 7. Place the reagent strip, with the test pads facing up, into the middle trough of the test strip table. Slide the strip along the table until it touches the end of the trough. Note: You
must place the test strip while the message PLACE TEST ON TABLE is on the
screen. It will appear for 10 seconds.
8. The table is automatically pulled into the Analyzer. The instrument will read each reagent area at a specified time. Results are available in one minute. Be sure not to 9. Remove the used Reagent Strip and discard it in the proper container. 10. Test results are automatically printed. Press the PRINT key to reprint the last set of test results. Press PAPER, if desired, to add blank lines after the results. Label the printout appropriately and place the results on the Decentralized Laboratory Testing Clinitek 50® Urine Dipstick Patient Log. Document the result on Unit (or other specific) 11. Wipe the test strip table with a damp, lint-free tissue. This should be done after IX. RESULT
REPORTING
A. Calculations: Results are obtained by a direct printout from the analyzer. No calculations are B. Performance of routine screening using Clinitek 50® Urine Chemistry Analyzer and Multistix® 10 SG urine dipsticks should be performed only by those that have, after satisfactory completion of the required orientation and training and having read and understood this procedure, have been authorized by the Decentralized Laboratory Testing Program. C. Staff competence is evaluated at regularly defined intervals, determined by Educational Services. Competency requirements are based upon an annual assessment of testing frequency, complexity of testing methodology, and consequences of an inaccurate result. Urine Dipstick competency is evaluated annually by psychomotor and cognitive measures. E. Staff will record observed results on Unit (or other specific) Flow Sheet. F. Staff must document appropriate billing for the test. X. EXPECTED
Glucose: Small amounts of glucose are normally excreted by the kidney. These amounts are usually
below the sensitivity of this test but on occasion may produce a color between the Negative and the 100 mg/dL color blocks and that is interpreted by the instrument as a positive. Results of the first positive level may be significantly abnormal if found consistently. Bilirubin: Normally no bilirubin is detectable in urine by even the most sensitive methods. Even trace
amounts of bilirubin are sufficiently abnormal to require further investigation. Atypical colors may indicate that bilirubin-derived bile pigments are present and may be masking the bilirubin reaction. Ketone: Normal urine specimens ordinarily yield negative results with this reagent. Detectable levels of
ketone may occur in urine during physiological stress conditions such as fasting, pregnancy and frequent strenuous exercise. In ketoacidosis, starvation or with other abnormalities of carbohydrate or lipid metabolism, ketones may appear in urine in large amounts before serum ketone is elevated. Specific Gravity: Random urines vary from 1.001 - 1.035.
Blood: The significance of the Trace reaction may vary among patients, and clinical judgement is
required for assessment in an individual case. Development of green spots (intact erythrocytes) or green color (free hemoglobin/myoglobin) on the reagent area indicates the need for further investigation. Blood is often, but not always, found in the urine of menstruating females. pH: Both the normal and abnormal urinary pH range is from 5 to 9.
Protein: Normally no protein is detectable in urine, although a minute amount is excreted by the normal
kidney. A reading anything greater than Trace indicates significant proteinuria. Clinical judgement is needed to evaluate the significance of Trace results. Urobilinogen: The normal urobilinogen range obtained with this test is 0.2 to 1.0 mg/dL (1 mg/dL is
approximately equal to 1 Ehrlich Unit/dL). A result of 2.0 mg/dL represents the transition from normal to abnormal, and the patient and/or urine specimen should be evaluated further. Nitrite: Normally no nitrite is detectable in urine. The proportion of positive nitrite test in cases of
significant infection depends on how long the urine specimens were retained in the bladder prior to collection. Indentification of known positive cases with the nitrite test ranges from as low as 40%, when little bladder incubation occurred, to as high as approximately 80%, when a minimum of four hours of Leukocytes: Normal urine specimens generally yield negative results: positive results (Small or greater)
are clinically significant. Individually observed Trace results may be of questionable clinical significance: however, Trace results observed repeatedly may be clinically significant. Positive and repeated trace findings indicate the need for further testing of the patient and/or urine sample in accordance with the medically accepted procedures for pyuria. Positive results may occasionally be found with random specimens from females due to contamination of the specimen by vaginal discharge. XI. LIMITATIONS
As with all laboratory tests, definitive diagnosis or therapeutic decisions should not be based on any Glucose: Ascorbic acid concentrations of 50 mg/dL or greater may cause false negatives for specimens
containing small amounts of glucose (75-125 mg/dL). Ketone bodies reduce the sensitivity of the test: moderately high ketone levels (40 mg/dL) may cause false negatives for specimens containing small amounts of glucose (75-125 mg/dL) but the combination of such ketone levels and low glucose levels is metabolically improbable in screening. The reactivity of the glucose test decreases as the specific gravity of the urine increases. Reactivity may also vary with temperature. Bilirubin: Indican (indoxyl sulfate) can produce a yellow-orange to red color response that may interfere
with the interpretation of a negative or a positive bilirubin reading. Metabolites of Lodine® (etodolac) may cause false positive or atypical results; ascorbic acid concentrations of 25 mg/dL or greater may cause Ketones: False positive results (Trace or less) may occur with highly pigmented urine or those
containing large amounts of levodopa metabolites. Compounds such as mesna (2-mercaptoethane sulfonic acid) that contain sulfhydryl groups may cause false positive results or an atypical color reaction. Specific Gravity: The chemical nature of the Bayer Diagnostics SG test may cause slightly different
results from those obtained with other specific gravity methods when elevated amounts of certain urine constituents are present. Highly buffered alkaline urines may cause low readings relative to other methods. Elevated specific gravity readings may be obtained in the presence of moderate quantities Blood: Elevated specific gravity may reduce the reactivity of the blood test. Capoten (Captopril) may
also cause decreased reactivity. Certain oxidizing contaminants, such as hypochlorite, may produce false positive results. Microbial peroxidase associated with urinary tract infection may cause a false positive reaction. Levels of ascorbic acid normally found in urine do not interfere with this test. pH: If proper procedure is not followed and excess urine remains on the strip, a phenomenon known as
“runover” may occur, in which the acid buffer from the protein reagent will run onto the pH area, causing a Protein: False positive results may be obtained with highly buffered or alkaline urines. Contamination of
the urine specimen with quaternary ammonium compounds (e.g., from some antiseptics and detergents) or with skin cleansers containing chlorhexidine may also produce false postive results. Urobilinogen: The reagent area may react with substances known to interfere with Ehrlich’s reagent,
such as p-aminosalicylic acid and sulfonamides. Atypical color reactions may be obtained in the presence of high concentrations of p-aminobenzoic acid. False negative results may be obtained if formalin is present. Strip reactivity increases with temperature; the optimum temperature is 22-26°C. The test is not a reliable method for the detection of porphobilinogen. The absence of urobilinogen Nitrite: Pink spots or pink edges should not be interpreted as a positive result. Any degree of uniform
pink color development should be interpreted as a positive nitrite test suggesting the presence of 10 or more organisms per mL, but color development is not proportional to the number of bacteria present. A negative result does not itself prove that there is no significant bacteriuria. Negative results may occur when urinary tract infections are caused by organisms that do not contain reductase to convert nitrate to nitrite; when urine has not been retained in the bladder long enough (four hours or more) for reduction of nitrate to nitrite to occur; or when dietary nitrate is absent, even if organisms containing reductase are present and bladder incubation is ample. Sensitivity of the nitrite test is reduced for urines with high specific gravity. Ascorbic acid concentrations of 25 mg/dL or greater may cause false negative results with specimens containing small amounts of nitrite ion (0.06 mg/dL or less). Leukocytes: Elevated glucose concentrations (≥ 3 g/dL) or high specific gravity may cause decreased
test results. The presence of cephalexin (Kelfex®), cephalothin (Keflin®), or high concentrations of oxalic acid may also cause decreased test results. Tetracycline may cause decreased reactivity, and high levels of the drug may cause a false negative reaction. XII. NOTES
A. Bayer Diagnostics Reagent Strips are for in vitro diagnostic use. B. Store reagent strips at room temperature between 15-30°C (59-86°C). Do not store bottle in direct sunlight. Protection against ambient moisture, light and heat is essential to guard against altered C. In clinical specimens, the sensitivity depends upon several factors: the presence or absence of inhibitory factors typically found in urine, the specific gravity, and the pH. D. Exact agreement between visual results and instrumental results might not be found because of the inherent differences between the perception of the human eye and the optical system of the E. The specific gravity test permits determination of urine specific gravity between 1.000 and 1.030. In general, it correlates within 0.005 with values obtained with the refractive index method. For increased accuracy, 0.005 may be added to readings from urines with pH equal to or greater than 6.5 Strips read instrumentally are automatically adjusted for pH by the instrument. XIII. REFERENCE
Bayer Diagnostics, Product Instructions for MULTISTIX® 10 SG Reagent Strip, 1992.

Source: http://pathology.uchc.edu/pdf/uid887.pdf