Department Of Pathology Point of Care Testing POC Quick Vue In-Line Strep A Version#4

Transcription

1 Department Of Pathology Point of Care Testing POC Quick Vue In-Line Strep A Version#4 Printed copies are for reference only. Please refer to the electronic copy for the latest version. A. Purpose: The QuickVue In-Line One-Step Strep A test allows for the rapid detection of group A streptococcal antigen directly from patient throat swab specimens. The test is intended for use as an aid in the diagnosis of group A streptococcal infection. B. Principle: To perform the test, a throat swab is collected and inserted into the test cartridge. The extraction solutions are mixed, resulting in a green color change, and added to the sample well. The extracted sample migrates by capillary action through a labeled pad consisting of a pink label containing rabbit polyclonal anti-strep A antibody and a blue control label. If the extracted solution contains strep antigen, the antigen will bind to the antibody coupled to the pink test label, which will, in turn, bind a second rabbit polyclonal anti-step A antibody spotted on the membrane, resulting in the formation of a pink-to-purple test line next to the imprinted T on the Test Cassette (positive result). The blue control line will also appear next to the letter C on the Test Cassette indicating that the reagents were mixed and added properly, proper volume of fluid entered the Test Cassette, and capillary flow occurred. A blue Control Line should always appear in a proper functioning Test Cassette. If strep A is not present, or at very low levels, only a blue Control Line will be visible (negative result). C. Policy: 1. A physician/pa s order is required 2. LifeBridge Health Trainers will be identified and trained on each unit performing Gastroccult and Strep A. 3. Certified Trainers will include an in service, satisfactory completion of a written examination and performance of a test. 4. Recertification will be performed yearly. 5. A record of Certified Operators and Trainers will be maintained on each nursing unit, Staff Development, and with the Department of Pathology. 6. Bedside Testing Team Leader/Technical Specialist will supply a report identifying problems to the Director of each unit. Effective Date: 09/04/2012 1

2 7. Documentation of follow-up investigation and corrective actions taken will be returned to Pathology to be maintained by Bedside Testing. 8. Results will be recorded in Powerform or on the Point-of-Care Testing Result Sheet. On Nursing Units at Sinai results will be entered as Other Tests in the Glucose Meter. 9. Any data entry or corrections of data entry made by operators will need to see Nursing Policies and Procedures for electronic entry and corrections when mistakes are made. 10. Specimens for testing at bedside and In-Lab are not to be obtained at the same time. Specimens need to be obtained individually. D. Specimen: 1. Specimen Type: Throat swab specimen 2. Patient Preparation: N/A 3. Handling Conditions: a. Sampling: Hold the tongue down with a sterile tongue depressor. Both tonsillar areas, the posterior pharynx, and any other areas of inflammation, ulceration or exudation should be sampled. Use only rayon tipped swabs on solid plastic shafts for specimen collection. Do not use calcium alginate, cotton tipped, hollow shafts or wooden shaft swabs. b. If a culture is desired, dual swabs or two sequential swabs can be taken to ensure adequate sample for the culture procedure. One swab alone cannot be used to perform the QuickVue test followed by a culture, as the extraction solution will destroy any viable bacteria on the swab. 4. Storage Requirements: Swab specimens should be processed as soon as possible after collection. 5. Rejection Criteria: N/A E. Equipment and Materials: 1. Equipment: N/A 2. Materials/ Supplies: a. Individually packaged test cassettes (25 or 75) containing a rabbit polyclonal antibody to Strep A (Test Line) and a control rabbit polyclonal antibody capable of binding the blue-colored control label (Control Line). b. Extraction Solution Bottles (25 or 75) containing 4M sodium nitrite with 0.01% thimerosal (0.6mL) and 0.2M acetic acid (0.65mL) inside a glass ampule. c. Individually packaged sterile rayon-tipped swabs on solid shafts (25 or 75). 1. Positive control swabs (+) (1 or 3) containing heat inactivated group A Streptococcus. 2. Negative control swabs (-) (1 or 3) containing heat inactivated group C Streptococcus. F. Preparation: N/A G. Performance Parameters: Effective Date: 09/04/2012 2

3 1. For in vitro diagnostic use only. 2. Do not use beyond the expiration date printed on the outside of the box. 3. Use appropriate precaution in the collection, handling, storage, and disposal of specimens, control swabs, and used kit contents. Discard used materials in a proper biohazard container. 4. The test cassette must remain sealed in the protective foil pouch until just prior to use. 5. If the Extraction Solution bottle is missing the glass ampule, or the solution is green prior to breaking the ampule, discard and use another Extraction Solution bottle. H. Storage Requirements: Store kit at room temperature (15 o C) out of direct sunlight. Kit contents are stable until the expiration date printed on the outer box. Do not freeze. I. Quality Control: The QuickVue In-Line One-Step Strep A test contains built-in control features. The manufacturer s recommendation for daily quality control is to document these controls for the first sample run each shift. 1. A control of the extraction procedure is provided by a color change from clear to green as the Extraction Reagents are mixed. The color change is an indication of extraction integrity and is also an indication that the extraction procedure was correctly performed. 2. The two color result format provides a clear-cut readout for positive and negative results. The appearance of a blue Control Line next to the letter C provides several forms of control. 3. First, detection components for the specimen and internal control are processed concurrently using identical procedures; therefore, the appearance of the Control Line assures that functional activity of the detection component is maintained. 4. Secondly, the appearance of the Control Line also ensures that the foil pouch integrity has been maintained and the Test Cassette has been stored in a manner so as to not compromise it s functionality. 5. Third, the appearance of the Control Line indicates that proper volume of fluid entered the Test Cassette and capillar flow occurred. This would indicate that the Test Cassette was assembled properly, by acting as a check for membrane interfaces and proper positioning of components. 6. Lastly, if the Control Line fails to develop, the test result is invalid. 7. A negative background control is provided by the clearing of background color in the Result Window and indicates that there were no immunological interfering substances in the specimen. The background color in the result window should be white to light pink within 5 minutes, and not interfere with the reading of the test result. If background color remains in the Result Window which interferes with your ability to read the test result, the test result may be invalid. Contact the Bedside Testing Coordinator or call Quindel Technical Effective Date: 09/04/2012 3

4 Assistance. 8. Materials Used: External controls may also be used to assure that reagent and assay procedure is performing properly. a. Positive and Negative Control Swabs are supplied in the kit. The positive (+) control swab is stored in the pink-capped tube; the negative (-) control swab is stored in the blue-capped tube. The positive control used must be traceable to an ATCC strain from 19615, and the negative control must be traceable to an ATCC non-group A Strep organism. To test: remove control swab from it s container and insert it into the Test Cassette Swab chamber, and continue with the assay as instructed in PROCEDURE step 6.3 below. b. Liquid Controls (Catalog #0354) may also be utilized. Hold the bottle vertically and place one free falling drop of the liquid control onto a sterile swab provided in the kit. Insert the swab into a Test Cassette Swab Chamber, and continue testing as outlined in PROCEDURE step 6.3 below. J. Proficiency Testing Surveys. a. Place a clean tube from the extraction kit into a test tube rack. b. Prepare the Extraction Solution Bottle as described in steps 6.3 and 6.4 below. c. Dispense 8 drops from the extraction solution bottle into the tube. Place the proficiency swab into the tube. Hold the bottom of the tube so the swab head is slightly compressed. Rotate the swab three times. d. Wait one minute. e. Express all the liquid from the swab head in the tube by rolling the swab against the inside of the tube and pressing slightly as it is withdrawn from the tube. Discard the swab. g. Fill the disposable dropper to the fill line with the solution from the tube and add the contents into the test Cassette Swab Chamber. h. Read the result at 5 minutes. K. Preparation and Handling: N/A L. Frequency Run: Positive and Negative controls will be tested for each 25 test kits. Bedside Testing Team Leader/Technical Specialist prior to distribution to units will perform Quality Control on each box of 25 tests. Each box will be labeled that QC was performed and that patient testing can now be performed. M. Tolerance Limits: N/A N. Corrective Action: N/A O. Recording and Storage of Data: N/A Effective Date: 09/04/2012 4

5 P. Procedure: 1. Apply gloves 2. Remove the Test Cassette from the foil pouch and place on a clean, dry, level surface. 3. Using the notch at the back of the chamber as a guide, gently insert the specimen into the Test Cassette Swab Chamber. 4. Hold the Extraction Solution bottle vertically, so that the tip is pointed upward. Carefully crush the glass ampule inside the bottle. 5. Invert the bottle, and shake vigorously four or five times to mix the solutions. Solution will turn green after the ampule is broken. Do not use the bottle if solution is green prior to breaking the ampule. Note: Solution must be used immediately. 6. Remove the cap. Hold the bottle pointing downward, approx. 1 to 1½ inches above the swab chamber. Using constant pressure, express 8 drops onto the swab tip located in the swab chamber. 7. Begin timing. If liquid has not moved across the Result Window in 1 minute, remove swab and gently re-insert it. The test cassette should not be moved or jarred again until the assay is complete and ready for interpretation. 8. Read results at 5 minutes. (Note: some positive results may be seen earlier). Q. Calculations: N/A R. Reporting Results: 1. Positive results: The appearance of any pink-to-purple line next to the letter T in the result window, along with a blue Control Line next to the letter C indicates a positive result for group A Streptococcus. 2. Negative Results: The appearance of only the blue Control Line next to the letter C in the results window indicates a negative result. A negative QuickVue test indicates that the specimen is a presumptive negative for the presences of group A Streptococcus. (Note: A negative test result might occur if the level of extracted antigen in a sample is below the sensitivity of the test. A follow up culture is recommended for all negative patient samples. 3. Invalid Results: The test result is invalid if the blue Control Line is not visible at 5 minutes. If this occurs either: retest using a new specimen and a new Test Cassette; call for assistance by contacting the Bedside Testing Coordinator; or alternatively, contact Quidel Technical Assistance at Patient Results: Are charted in Powerform or using the Point-of-Care result sheets. The white copy goes on the patient s chart, and the yellow copy is to be sent to the Bedside Testing Coordinator in pathology. S. Procedure Notes: T. Reference Range: N/A U. Critical Value: N/A Effective Date: 09/04/2012 5

6 V. Reporting Format: Results will in Powerform or recorded on the Point-of-Care Result Sheet. W. Hazardous Materials: 1. The Extraction Solution bottle contains an acidic solution. If the solution contacts the skin or eyes, flush with large volumes of water. 2. The Extraction Solution bottle contains glass, break cautiously. X. Protective Equipment Requirements: Gloves V. Performance Characteristics: Multi-center field study evaluation of the QuickVue test was conducted,using sheep blood agar cultures followed by a latex agglutination assay confirmation as the standard. A total of 537 specimens were analyzed. 301 specimens were tested by users in the field, and 236 were frozen and shipped overnight to QUIDEL for testing. Specificity: in the field: 94% At QUIDEL: 99% Sensitivity: in the field: 87% At QUIDEL: 92% Overall Agreement between SBA culture and QuickVue was 96% (See Reference for details.) W. Liminations of Procedure X. Linearity: N/A Y. Interfering Substances Z. Chemical Interference: N/A AA. In vivo Interference: 1. Heavy colonization by Staphylococcus aureaus (>10 10 ) can yield false positive results. 2. Respiratory infections, including pharyngitis, can be caused by Streptococcus from serogroups other than groupa, as well as by other Pathogens 3. The QuickVue test will not differentiate asymptomatic carriers of group A Streptococcus from those exhibiting streptococcal infection. BB. References: QuickVue In-Line One-Step Strep A Test Physician s Office Laboratory Procedure Manual, March 1996 QUIDEL McKellar Court San Diego, CA Effective Date: 09/04/2012 6