Procedure. Applies To: UNM Hospitals Responsible Department: Rapid Response Laboratory Revised: 3/2015

Transcription

1 Applies To: UNM Hospitals Responsible Department: Rapid Response Laboratory Revised: 3/2015 Procedure Patient Age Group: ( ) N/A (X ) All Ages ( ) Newborns ( ) Pediatric ( ) Adult DESCRIPTION/OVERVIEW 1. PURPOSE 1.1. The Siemens Clinitek Status Analyzer is a portable instrument for reading Siemens urinalysis strips. Test results may provide information regarding the status of carbohydrate metabolism, kidney and liver function, acid/base balance, urinary tract infection, urine concentration, and other metabolic states. Urinalysis dipstick testing is a waived qualitative assay used for screening purposes only. 2. PRINCIPLE 2.1. 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 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 Ketone 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 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 concentration Blood This test is based on the peroxidase-like activity of hemoglobin, which catalyzes the reaction of diisopropylbenzene 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 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 is based on the protein-error-of-indicators principle. At a 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 Urobilinogen This test is based on a modified Ehrlich reaction, in which a ρ-diethylaminobenzaldehyde in conjunction with a color enhancer reacts with urobilinogen in a strongly acid medium to produce a pink-red color 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, nitrite in Page 1 of 7

2 the urine reacts with ρ-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 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 salt to produce a purple color. REFERENCES Siemens Clinitek Status Analyzer Operator s Manual Rev. A, Siemens Clinitek Status Connect System Operator s Guide Rev. A, The most recent Siemens HealthCare Urine Dipstick Package Insert, Tarrytown, NY, 10594; 6/2010 AREAS OF REPONSIBILITY 1. POCT Urine Dipstick and Urine pregnancy testing can be done on any inpatient or outpatient at University Hospital on receipt of an order from a licensed independent practitioner. 2. Staff who have satisfied the required competency requirements may perform the test; refer to the POCT Quality Assurance procedure. PROCEDURE 1. SUPPLIES 1.1. Siemens Clinitek Status Analyzer 1.2. Siemens brand urinalysis Reagent Strips 1.3. Commercially Available Normal and Abnormal Quality Control Solutions 2. ORDERING INFORMATION 2.1. Siemens brand urinalysis Reagent Strips are ordered through CDU Quality Controls are coordinated through the UH POCT office. Please contact the UH POCT office at for assistance. 3. STORAGE 3.1. Urinalysis reagent strips are stored at room temperature in the original bottle. Transfer to any other container may cause reagent strips to deteriorate and become non-reactive Strips are stable until the expiration date printed on the bottle. Do not use expired strips. Do not use discolored or faded strips Do not store the bottle in direct sunlight. Do not remove the desiccant from the bottle Quality control material will expire per manufacturer s guidelines. 4. CALIBRATION 4.1. The instrument performs a system test each time it is turned on. Then, each time a test is run, the instrument automatically calibrates. The white calibration bar (on the test table) provides National Institute of Standards and Technology (NIST) traceable calibration. 5. MAINTENANCE 5.1. The test table insert and the test table should be kept clean Test Table Insert Remove insert Rinse both sides of the table insert under running water. Dry and replace insert Test Table Remove the test table by pulling it slowly out of the analyzer. Lift the test table insert from the test table, drain the drip tray if necessary Wet a cotton-tipped stick or gauze and carefully clean test table, except for white calibration bar Dry the test table thoroughly with gauze. Page 2 of 7

3 Reinsert the test table into the analyzer by holding the table at the end opposite the white calibration bar, with the white calibration bar facing upwards. Push the test table firmly but slowly, just over halfway into the analyzer Replace the test table insert White Calibration Bar Check the calibration bar on the test table regularly and always after a strip jam If the white calibration bar is dirty or discolored, gently wipe it clean with a new cottontipped stick or gauze wetted with distilled water. Allow the calibration bar to air dry and then inspect the surface for dust, foreign material, scratches or scuffs. If the Calibration bar cannot be cleaned or is still marked, obtain a new test table. Reinsert the test table Instrument Exterior Always keep the outside of the instrument clean and free of dust Turn the instrument off before cleaning Wipe the outside (including the display) with a damp (not wet) gauze and a mild detergent. Do not spray cleaner directly onto the instrument Care should be taken to avoid liquid from entering the printer compartment. 6. QUALITY CONTROL 6.1. Urine Dipstick QC Positive and Negative Control solutions should be tested each day of patient testing and when a new vial of strips is opened, prior to use Once QC has been performed on each new vial of strips, label each new vial with QC d and initial and date Press the QC test button on the Clinitek touch screen Select QC test strip. The Control Lot screen displays with the negative control displayed Enter the Control lot number and select Enter The Control expiration screen displays Use the arrow keys to indicate the control lot expiration date, select Enter The Strip Lot screen displays Enter the Strip lot and select Enter The Strip Expiration screen will then display. Use the arrow keys to indicate the strip lot expiration date and select Enter The Prepare Test screen displays Press the start button. (The test will begin in 8 Seconds) Apply the quality control specimen to each pad on the strip, using care not to touch the vial tip to the pads Tap the strip on its side on an absorbent cloth to remove excess urine Place the reagent strip onto the Clinitek test strip holder with test pads facing up, sliding the strip to the end of the strip holder The test table will retract into the instrument The screen will display the results. Pass or Fail will be displayed at the top of the screen Repeat with the positive quality control solution If QC is out of range, document corrective action and rerun. If it is still out of range discontinue patient testing and contact the Point of Care office. 7. PATIENT MANAGEMENT 7.1. Patient Identification Refer to the hospital procedure Patient Preparation Page 3 of 7

4 The operator must describe to the patient the purpose and steps of the procedure before testing can begin. 8. SPECIMEN COLLECTION AND HANDLING 8.1. Standard precautions apply to all point of care tests Testing personnel should handle all patient samples as per the Bloodborne Pathogen Exposure Plan Collect freshly-voided urine in a clean, dry container and test as soon as possible Urine Dipstick-The container and specimen volume should allow for complete dipping of all reagent strip areas. If there is not enough sample for complete dipping use a pipette to saturate all reagent strip areas Urine Pregnancy-The assay requires a few drops of urine If unable to test immediately, refrigerate the specimen and let it return to room temperature before testing. 9. SPECIMEN LABELING 9.1. The specimen should be labeled as per the Hospital s Specimen Procedure. 10. PATIENT TESTING Mix urine specimen well just before testing Remove one urine test strip from the bottle At the main SELECT screen, touch STRIP TEST Scan your Operator ID and select Enter Select ENTER NEW PATIENT ID Scan the Patients Financial Number and select ENTER Urine Dipstick Test Select START Dip all the test pads of the strip into the urine Immediately remove the strip Drag the back edge of the strip against the container rim to remove excess urine Tap the strip on its side onto an absorbent cloth to remove excess urine Place the reagent strip onto the Clinitek test strip holder with test pads facing up, sliding the strip to the end of the strip holder The test table will automatically retract into the instrument The analyzer will perform an automatic calibration and begin analyzing the strip While the strip is being analyzed, a SELECT APPEARANCE screen will be displayed If the urine is yellow and clear, touch the YELLOW AND CLEAR button If the urine sample is not yellow and clear, touch the OTHER button for more choices. 11. INTERPRETATION OF RESULTS Urine Dipstick Test Protein: Clinical judgment is needed to evaluate the significance of Trace results Blood: Small amounts of blood ( mg/dl or a strip result of Small) are sufficiently abnormal to require further investigation. The significance of the Trace reaction may vary among patients and clinical judgment is required for assessment in an individual case Leukocytes: Trace results may be of questionable clinical significance; however, Trace results observed repeatedly may be clinically significant. f A result of Small or greater is a useful indicator of infection Nitrite: Nitrite concentration during infection increases with the length of time the urine specimen is retained in the bladder prior to collection. A minimum of four Page 4 of 7

5 hours of bladder incubation significantly increases the likelihood of obtaining a positive result Glucose: Results at the first positive level may be significantly abnormal if found consistently Ketone: In ketoacidosis, starvation or with other abnormalities of carbohydrate or lipid metabolism, ketones may appear in urine at levels of 10mg/dL or higher before serum ketone levels are elevated. Clinical judgment is needed to determine the significance of Trace results, which may occur during physiological stress conditions such as fasting, pregnancy and frequent strenuous exercise Specific Gravity: The instrument automatically adds to readings from any urine with a ph Bilirubin: The sensitivity is not sufficient to detect early phases of liver disease and a negative value may warrant testing by a more sensitive method Urobilinogen: 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 for hemolytic and hepatic disease. 12. REFERENCE RANGE All POC testing done at UNMHSC has a normal reference range validated with those tests performed in the laboratory. See the table below. 13. RESULT REPORTING 13.1.Patient results should be immediately recorded in the permanent medical record Results that appear to be inconsistent with patient therapy or condition should be viewed as questionable and the test should be repeated by the laboratory reference method. NORMAL RANGE: ph: Specific Gravity: Urobilinogen Normal (0.2) A normal dipstick is negative for leukocytes, nitrite, protein, glucose, ketones, urobilinogen, and blood. Normal appearance is yellow and clear REPORTABLE/SENSITIVITY RANGE: Reportable Range Sensitivity Range Protein: Negative 2000 or more mg/dl mg/dl albumin Blood: Negative Large/ mg/dl Leukocytes: Negative Large/ WBC/hpf in Nitrite: Negative Positive mg/dl nitrite ion Glucose: Negative 2000 or more mg/dl mg/dl glucose Ketone: Negative Large/160 mg/dl 5 10 mg/dl acetoacetic acid ph: Specivfic Gravity: Bilirubin: Negative Large/ mg/dl bilirubin Urobilinogen: Negative 8 mg/dl 14. INTERFERING SUBSTANCES AND LIMITATIONS Protection of test strips against exposure to light, heat and ambient moisture is mandatory to guard against altered reagent reactivity. Page 5 of 7

6 14.2. Substances that cause abnormal urine color may affect the readability of test pads on urinalysis reagent strips. These substances include visible levels of blood or bilirubin and drugs containing dyes, nitrofurantoin or riboflavin Levels of ascorbic acid normally found in urine do not interfere with these tests Test pads should not be read after two minutes; color changes that occur after this time are of no diagnostic value Discoloration or darkening of the test pads may indicate deterioration. If this is evident, or if test results are questionable or inconsistent with expected findings, the following steps are recommended: Confirm that the product is within the expiration date shown on the label Check performance against known negative and positive control materials Retest with fresh product If proper results are not obtained, contact point of care testing at Protein - Contamination of the urine specimen with skin cleansers containing chlorhexidine may affect protein (and to a lesser extent specific gravity and bilirubin) test results. The user should determine whether the use of such skin cleansers is warranted Fresh urine should be used for optimal results with the tests for bilirubin and urobilinogen, as these compounds are very unstable when exposed to room temperature and light Blood - A visibly bloody urine may cause falsely elevated results Capoten (captopril) may reduce the sensitivity Certain oxidizing contaminants, such as hypochlorite, may produce false positive results Leukocytes - Microbial peroxidase associated with urinary tract infection may cause a false positive reaction Elevated glucose concentrations ( 3 g/dl) may cause decreased test results The presence of cephalexin (Keflex), 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 Positive results may occasionally be due to contamination of the specimen by vaginal discharge Nitrite - Pink spots or pink edges should not be interpreted as a positive result A negative result does not rule out significant bacteriuria False negative results may occur with shortened bladder incubation of the urine, absence of dietary nitrate, or the presence of nonreductive pathological microbes Glucose - 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 ( mg/dl) but the combination of such ketone levels and low glucose levels is metabolically improbable in screening Ketone - False trace results may occur with highly pigmented urine specimens 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 ph - Bacterial growth by certain organisms in a specimen may cause a marked alkaline shift (ph >8.0), usually because of urea conversion to ammonia Specific Gravity - The Siemens SG test is dependent on ions in urine and results may differ from those obtained with other specific gravity methods when certain nonionic urine constituents, such as glucose, are present. Page 6 of 7

7 Highly buffered alkaline urines may cause low readings, while the presence of moderate quantities of protein ( mg/dl) may cause elevated readings Bilirubin - Indican (indoxyl sulfate) can produce a yellow-orange to red color response that may interfere with the interpretation of a negative or positive reading. Metabolites of Lodine (etodolac) may cause false positive or atypical results Atypical colors (colors that are unlike the negative or positive color blocks shown on the color chart) may indicate that bilirubin-derived bile pigments are present in the urine sample and may be masking the bilirubin reaction. These colors may indicate bile pigment abnormalities and the urine specimen should be tested further Urobilinogen - The test pad may react with interfering substances known to react with Ehrlich s reagent, such as ρ-aminosalicylic acid and sulfonamides Atypical color reactions may be obtained in the presence of high concentrations of ρ- aminobenzoic acid False negative results may be obtained if formalin is present Strip reactivity increases with temperature; the optimum temperature is C. The test is not a reliable method for the detection of porphobilinogen. CLIA Classification Use If definitive, how will results be used? Waived Urine Dipstick- Screen; Urine Definitive Provide information on the kidney, liver function, acid base balance, urinary tract infection and pregnancy. SUMMARY OF CHANGES Minor formatting changes, added to QC each new vial of strips and label QC d and initial/date. Removed references to tesing urine HCG cassettes on the instrument. Replaces POCT: Siemans Clinitek Status Connect, 12/2010. RESOURCES/TRAINING Resource/Dept Point-of-Care Department Contact Information DOCUMENT APPROVAL & TRACKING Item Contact Date Approval Owner Point of Care Testing Coordinator/Point of Care Consultant(s) Tricore Reference Laboratories Committee(s) Point of Care Testing Advisory Committee, Clinical Operations PP&G Committee, Nurse Practice PP&G Subcommittee Y Nursing Director Sheena Ferguson, Chief Nursing Officer N/A Medical Director Matthew Luke, MD; Rapid Response Laboratory Y Official Approver Erin Doles, Administrator, Professional & Support Services Y Official Signature Date: 4/8/2015 Effective Date 4/8/2015 Origination Date 6/2007 Issue Date Clinical Operations P&P Coordinator 4/9/2015 ar ATTACHMENTS None. Page 7 of 7