LABORATORY 6: The Complete Urinalysis with Automation

Transcription

1 LABORATORY 6: The Complete Urinalysis with Automation PreLab Preparation: 1. Review YouTube videos on Clinitek Status Principle & Operation Performing a UA Cleaning the reference strip Note: do not attempt this procedure without instructor s permission and supervision! 2. Review the corresponding information in the course textbook(s) as well as the classroom notes in preparation for this lab and to aid in answering the study questions. Points Points are awarded for prelab assessments, skills, as well as successful and timely completion of study questions. Objectives According to the standards set by the instructor and following appropriate demonstrations, the student will: 1. observe the instructor s demonstrations of care, handling, operation and quality control procedures of the urine analyzer. 2. mentor and evaluate one or more classmates on the operation of the Siemens Clinitek Status+. 3. perform routine maintenance and quality control on an automated urine analyzer as directed. 4. analyze assigned urine samples to obtain dipstick results within ± 1 pad reading of the instructor s results and matching microscopic results ± 20% as outlined in the Microscopic Lab. 5. record results accurately. 6. analyze quality control results to determine quality control acceptability. (One set of controls per instrument will be performed and all students who use that instrument will record and utilize the information.) 7. recognize abnormal dipstick and microscopic results as have been outlined in previous lab exercises. Equipment and Supplies 1. Siemens Clinitek Status+ urine chemistry analyzer 2. Urine specimens (5 or more), appropriate urine controls with expected results sheet. 3. Multistix 10 SG reagent strips 4. Centrifuge, microscope, centrifuge tubes, Sharpie marker, Kim-wipes, microscope slides and cover glasses. 5. Clinitest, Acetest, and Ictotest supplies, reagent tablets and product inserts. 6. Color reference pictures of urinary sediment. Urinalysis Instrumentation & Related Information The biggest preventable variable in urinalysis results comes from the mis-reading/mis-interpreting of the dipstick results. The solution to this problem is utilization of an automated urine dipsick reading instrument. Advantages to use of such instrumentation includes: increased efficiency, improved precision, accuracy and reproducibility. 1

2 Inside the urinalysis dipstick reader, a filtered focused light is directed to the dipstick pad where, depending on the depth of pad s reacted color, some of it is absorbed and the remainder is bounced/reflected to a photocell - detector. The signal created in the photocell detector is sent to the instrument s on-board computer which compares the amount of reflected light detected to that of known concentrations of the analyte/substance being measured and displays the appropriate concentration for the amount of light detected from this analysis. Urinalysis dipstick reading instruments vary greatly in size, cost and the tasks they perform, but all strip readers evaluate the reactions on the dipstick at specified times. Their accuracy depends on the operator s skill and accuracy in appropriately identifying the sample, mixing, dipping, blotting, getting the strip onto the tray and activating the timer appropriately. Higher end instruments add the urine to the strip and automatically activate the timing mechanism. There are also instruments capable of performing the complete UA from evaluating the physical and chemical properties through the microscopic. See reference listings for sources of additional/general information on automated urinalysis. Laboratory informatics Where the Clinitek Status Analyzer is a suitable instrument for low volume clinics, educational settings and doctor s offices; the larger and more automated urinalysis analyzers with on-board computers capable of interfacing with the laboratory mainframe computer is standard equipment in the modern hospital laboratory. In today s modern laboratory a system of computers and software programs exchange data about patients, test requests and test results. This is known as a Laboratory Information System or LIS. The LIS is interfaced with the Hospital Information System. This system enables the hospital and lab to order the correct test requests for each patient, keep track of individual patient or specimen histories, and help guarantee a better quality of results as well as printing hard copies of the results for patient charts and apply appropriate billing. Siemans Clinitek Status+ Analyzer The Siemans Clinitek Status+ Analyzer is a semi-automated, benchtop instrument designed to read the Siemans Multistix 10 SG Reagent Strip. Like most urine dipstick readers, this analyzer works on the principle of reflectance photometry. The instrument s optical system consists of six light emitting diodes, a light guide, a mirror, a lens and a detector. Light from the LEDs travels along the light guide and is reflected off the calibration bar, strip or cassette onto the mirror. It is then directed through an aperture on the lens, from where it is focused onto the detector. The light intensity detected is converted into electrical impulses, which are processed by the instrument s microprocessor and converted into clinically meaningful results. The programming module for the Multistix 10 SG Reagent Strips contains programming information necessary to read the reagent strip areas for testing of glucose, bilirubin, ketone (acetoacetic acid), blood, ph, protein, urobilinogen, nitrite, and leukocytes. The instrument is programmed with such information as wavelengths, error messages, operating sequence, and algorithms needed to convert reflectance into clinically meaningful results. A white plastic strip located at the end of the feed table insert, provides a reflectance surface for the internal calibration of the instrument s optical system. Calibration is accomplished automatically by the measurement of reflected light from the calibration strip surface. The calibration strip (aka - the white bar) must be kept clean for proper instrument calibration. Equipment Maintenance: The Siemens Clinitek Status+ Students working with these instruments must, under the direction of their instructor(s), follow the manufacturer s written directions for maintenance and operation. Any information presented in this lab is subject modification based on manufacturer s directions. Though students will work in pairs, each student must independently perform the instrument s basic maintenance (tray cleaning) as follows. 1. Tray cleaning - The tray should be cleaned daily or more often if buildup is seen/suspected. a. Remove table by simply pulling it out; be careful that the white bar at the top of the tray does not become in the process. b. Clean strip area using a cotton-tipped applicator wetted with distilled water. Rinse both sides of table. c. Dry carefully and thoroughly. 2

3 2. Disinfect the table. If the table is in need of disinfection, one of several solutions is safe to use: Cidex, Theracide, Amphyl, 5% household bleach and Isopropyl alcohol (70-80%). Most area laboratories use 5% household bleach or 70% Isopropyl alcohol. Rinse the table with distilled water; dry thoroughly. Again, do not touch the white bar as it is used by the instrument for calibration. Periodically, check the white bar to insure that it is free of dust, scratches or other marks. If it is scratched or has other marks on it, bring it to the attention of the course instructor. Damaged white bars must be replaced. 3. Changing the paper roll (discussed, not performed unless needed) a. Pull out the remainder of the paper from the existing roll b. Open cover and remove the paper core. c. Insert new paper roll so that paper unrolls from underneath d. Trim insert end to resemble a large V shape. e. Insert paper under printer roller until the paper comes through other side of roller. Pull paper towards the back. Do not pull paper up or to the front as it may damage the printer. f. Feed paper through printer cover and snap cover into position. Basic Reactions and Expected Results Note: A complete explanation of reaction principles is found in the Multistix 10 SG product insert. Constituents analyzed are as follows: Analyte Expected reaction Glucose: Glucose Oxidase-peroxidase method. Negative for normal samples Bilirubin: Diazotized dichloroaniline method. Negative for normal samples Ketone: Nitroprusside test. Negative for normal samples Specific gravity: By indicator dye. Range: Test indicates how dilute or concentrated the urine. Blood: Peroxidase like activity of hemoglobin. Negative for normal samples ph: By double indicator. Dipstick range: 5 to 9; normal patient Protein: Protein-error-of-indicators principle. Negative for normal samples Urobilinogen: A modified Ehrlich reaction mg/dl reported as * Normal. Higher levels are reported as a number representing an amount in mg/dl. Nitrite: Reaction of nitrite with p-arsanilic acid. Negative for normal samples Leucocytes: Detection of leucocyte esterase enzyme. Negative for normal samples *Note: In the normal urine sample, the constituents/tests are reported as being Negative with the following exceptions: specific gravity, ph and urobilinogen. Quality Control Review specific manufacturer s recommendations. 1. Instrument calibration is performed internally by the instrument before each strip. Error codes are displayed on the screen. 2. Store controls at 2-8C. Do not freeze. If properly handled, the controls are stable until the expiration date stated on the label. 3. On initial use, the controls must be labeled date, time, and initials of medical laboratory technician. Expiration date must be noted on the control bottle when it is opened. 4. After removing the controls from the refrigerator, they must be allowed to come to room temperature (25-25 C); about 15 to 30 minutes. All specimens; control and patient samples, must be tested at room temperature to obtain accurate results. 5. Control (and patient samples) should be protected from direct sunlight and never subjected to a heat source. 6. Positive and negative controls will be analyzed during each laboratory. 7. Control results must be placed on the student report sheet. Any discrepancies must be brought to the instructor s attention. 3

4 Reference Siemens Clinitek Status+ users guide ( chure_update_rev02.pdf). Procedures and Sample Analysis 1. Review instrument routine maintenance, quality control and operation procedures outlined in this document. Observe demonstration(s) / PowerPoint presentation. 2. Students will work in pairs, coaching and monitoring these procedures. Each student pair must equally participate in the performance of these activities. 3. Obtain and organize supplies and specimens. All control and patient urine samples must be at room temperature and well mixed prior to testing. 4. If needed, turn analyzer on by depressing button located on right side of top surface. Instrument requires a short warm-up period; when complete, the tray table will be opened. Take care not to bump or jar the tray table. 5. Basic maintenance: Clean tray table on initial startup and upon completion of the shift. (See procedure for cleaning tray table under Equipment Maintenance.) When students are working in pairs, one member will clean tray table before sample analysis and other student will clean it after the lab activities are completed. 6. Sample testing procedure. (applies to quality control and patient samples) a. Remove a Siemans Multistix 10 SG Reagent Strip from its bottle and place it on a clean dry paper towel. Reclose bottle to prevent moisture from contaminating unused strips. b. Select STRIP TEST on the Clinitek Status+ instrument s main screen. c. Mix well, by inversion, the room temperature control or patient sample to be tested. d. Using appropriate dipstick technique, completely immerse all reagent areas of the dipstick into the specimen (either control or patient sample). Immediately remove the strip while running the edge along the specimen container s side. e. With your free hand, immediately touch START on the instrument screen thereby * activating the instrument s timing mechanism. f. Keeping the strip horizontal, touch its side (2X) to a clean paper towel to remove excess specimen. g. Immediately place the strip into the notched area of the instrument table, pad s side up and as far forward as possible. Be sure the strip is lying flat in the strip holder. NOTE: The strip must be in correct position on the holder within 8 seconds of activation of the instrument s timing mechanism. 7. Instrument will move the strip into the reading area automatically. Do not interfere with the instrument including the dipstick holder during this time. 8. After the strip is in the instrument, you can change the description of the color and clarity, if needed. The process is outlined in the YouTube video; consult operator s manual for specifics. 9. At the end of the incubation period, the instrument will display the results and provide a printed copy. Abnormal results will be marked with an asterisk (*) symbol. 10. Record the results using the format presented. 11. If the patient info has not been printed on the results paper, you must write it on the paper. Staple the instrument results to your report sheet. 12. Record results according to facility policy. See Below. 4

5 URINALYSIS REPORT SHEET XYZ Medical Clinic 2243 Round Rock Road Austin, Texas Name Date /10 points Control 1 Lot # Control 1 Exp Date Control 2 Lot # Control 1 Control 1 expected results Control 2 Control 2 expected results Control 2 Exp Date Multistix: Glucose Negative mg/dl Trace 3+ Within Range? Yes or No (If No, must bring to instructor s attention and add a comment - as to course of action.) Whether yes or no, you must include your initials! Lot#: Exp Date: Bilirubin Negative Small Large Ketones Negative mg/dl Trace Large Sp. Gravity Blood Negative cells/ul Trace Large ph Protein Negative Trace ->= 300 mg/dl Trace 3+ Urobilinogen 0.2 mg/dl 2 8 mg/dl Nitrite Negative Positive Leukocyte Esterase Negative Trace - Large Microscopic only if indicated by manufacturer AND directed by instructor ADDITIONAL TESTING Perform the following tests as directed by the instructor. *Reminders: 1. In the Comments box, you must state Yes or No whether or not the controls have given expected results and include your initials. 2. If at any time, a control sample does not give the expected result, you must note it under Comments and bring it to the instructor s attention. Back-up / Confirmatory Tests 3% SSA (for protein) Control 1 Control 1 Expected results Control 2 Control 2 expected results *Comments: Within Range? Yes or No? Acetest (ketones) Ictotest (bilirubin) Clinitest (reducing substances) Controls performed by: Date: 5

6 XYZ Medical Clinic, Austin, Texas Student Name Date / 25 points Specimen Patient Name Patient ID # Physical Properties Multistix: Lot#: Exp Date: Color Transparency Glucose (mg/dl) Bilirubin (negative) Ketone (mg/dl) Specific Gravity Blood (negative) ph ( ) Protein (mg/dl) Urobilinogen (mg/dl) Nitrate (negative) Leukocyte (negative) Microscopic (With the exceptions of Casts and Mucous, all microscopic elements are quantified under hpf. Elements listed in Other must be identified as well as quantified.) WBC (hpf) RBC (hpf) Squamous epi (hpf) Other epi (hpf) Bacteria (hpf) Crystals (hpf) Mucus (lpf) Casts (lpf) Other Back-up / Confirmatory Tests (Identify which, if any, confirmatory tests to be performed on this sample.) Testing performed by: Date: 6

7 Mentoring Check Off Sheet Student Name Date / 10 points Lab Partner / Mentor s Name This sheet is to be provided to the student lab partner / mentor named above who is responsible for its completion. The student named above is responsible for turning this sheet in along with their lab report. For acceptable completion of this exercise, the student can have no more than two (2) Needs Improvement checkmarks. Three to five point deductions are taken for Needs Improvement checkmarks. Items marked with (*) are critical items, worth more points and must be performed acceptably. Skill / Activity Acceptable Needs Improvement 1. Describes purpose of the test. 2. * Demonstrates compliance with Standard Precautions; ie. wears gloves (Others? ) 3. Cleans / disinfects the test strip table 4. *Removes one strip from the container and immediately replaces the cap. 5. Removes the strip immediately after dipping in sample and presses START key. 6. *Blots side and back of strip on paper towel, to remove excess urine. 7. Places the strip, with test pads facing up, into the middle trough of the test strip table. The strip must touch the end of the trough. 8. *Does not move or bump the table. 9. Notes the results as displayed on the screen OR obtains printed results. 10. *Discards used strip in proper container. 11. *Following manufacturer s recommendations, wipes table clean of residue 12. * Reports the result in the appropriate log or record. 13. *Allows refrigerated controls & samples to reach room temp prior to testing. 14. *Mixes controls & samples before dipping. 15. *Successfully runs and evaluates two levels of controls prior to turning out patient sample results. 16. Checks to see that lot numbers on the QC bottles match the expected results sheet. 17. Takes appropriate action if QC results are out of range. Such as: * repeating test *informing mentor AND instructor referring to instrument troubleshooting chart in manual **IF this situation does occur, student MUST explain the appropriate action to the mentor! Total number of checkmarks *** Student mentor s signature 7

8 Laboratory Exercise #6: Study Questions Student Name Date / 40 points Instructions: Answer the questions as appropriate; unless otherwise stated, each question is worth one point. The following Lab Study Questions are to review you on previously covered information as well as current lab material and are due by the end of the next lab period. Using lecture notes, reading assignments and information presented in this and previous UA labs, answer the following questions. (3 points) 1. What would be the immediate and long term effects on the Siemens Clinitek Status+ instrument of not blotting the urine strips before placing them in the tray/table? (Note this is a 3 point question, your answer must reflect some thought and substance.) 2. Name at least two (2) instruments that automatically read dipstix. (2 points) 3. A well-mixed fresh urine specimen is divided into 2 samples. Sample A is tightly capped and refrigerated for 4 hours, while Sample B is left on the bench-top near a sunny window. A complete urinalysis is performed independently on each sample. Explain how & why the test results could be different. (Assume: Sample A is brought to room temp before testing. (2 points) 4. List at least two causes for false positive results in the protein area of the dipstix? 5. Which serum protein is most likely to be found in the urine? 6. Testing for ketones has been proven useful in the monitoring of what metabolic disease condition? 7. Which of the following would NOT cause a false positive protein on the urine dipstick? A. A highly buffered urine sample B. Detection of proteins other than albumin C Over-dipping or leaving the strip in the urine sample for too long D. Contamination by quaternary ammonium compounds 8. What is the primary reagent in the dipstick region that tests for the ketones? (3 points) 9. List the three (3) ketone bodies and indicate which one is NOT detected by either the dipstick or the backup test. 8

9 10. Testing for ketones has been proven useful in the monitoring of what disease condition? (2 points) 11. What two (2) dipstick tests provide the most information regarding an urinary tract infection (UTI)? 12. Complete the following: The dipstick reaction for bilirubin is based on the reaction. 13. What is indicated in a urine sample that demonstrates a positive glucose dipstick and a negative Clinitest result? 14. What is indicated in a urine sample that demonstrates a negative glucose dipstick and a positive Clinitest result? 15. Explain the expression protein error of indicators. 16. Distinguish between hematuria and hemoglobinuria. 17. What is orthostatic proteinuria? (2 points) 18. Give at least two (2) clinical conditions/reasons why a person may have ketones in their urine. (3 points) 19. List three different substances/structures that are detectable on the blood portion of the dipstick. 9

10 (3 points) 20. Match the following abnormal crystals with their description. Crystal s name description Bilirubin Cystine Leucine Tyrosine Ampicillin Cholesterol 1. Colorless hexagonal plates 2. Rectangular plates with notched corners usually of 90 angles, associated with very high specific gravity. 3. Short, brilliant yellow - orange needles often attached to cellular products. 4. Dark, oily, refractile, yellow-brown spheres with concentric circles and radial striations. 5. Dark, very fine retractile needles with sharp points occurring in sheaves. 6. Long thin, colorless needles, form after refrigeration - rarely seen. (4 points) 21. Describe the classical macroscopic and microscopic characteristics of urine obtained from an out of control diabetic. Put your results in the table below. Urine characteristics of the out of control diabetic patient. Physical properties Expected Chemical properties Commonly found Microscopic properties specific gravity level color & clarity (Low, Normal, High?) Circle one 22. Explain how the nitrite portion of the dipstick can be negative for a patient with a UTI. 23. Explain how you can have a positive nitrite test and a negative leukocyte esterase result. (2 points) 24. Compare and contrast diabetes mellitus and diabetes insipidus by completing the following table. diabetes mellitus diabetes insipidus deficient hormone specific gravity level 10