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One Step Strep A Rapid Test Cassette (Throat Swab)
Cat. No.: RH0507I
A rapid test for the qualitative detection of Strep A antigen in throat swab specimens. For professional in vitro diagnostic use only.
The Strep A Rapid Test Cassette (Throat Swab) is a rapid chromatographic immunoassay for the qualitative detection of Strep A antigen from throat swab specimens to aid in the diagnosis of Group A Streptococcal infection.
Streptococcus pyogenes is non-motile gram-positive cocci, which contains the Lancefield group A antigen that can cause serious infections such as pharyngitis, respiratory infection, impetigo, endocarditis, meningitis, puerperal sepsis, and arthritis.1 Left untreated, these infections can lead to serious complications, including rheumatic fever and peritonsillar abscess.2 Traditional identification procedures for Group A Streptococci infection involve the isolation and identification of viable organisms using techniques that require 24 to 48 hours or longer.3,4
The Strep A Rapid Test Cassette (Throat Swab) is a rapid test to qualitatively detect the presence of Strep A antigen in throat swab specimens, providing results within 5 minutes. The test utilizes antibodies specific for whole cell Lancefield Group A Streptococcus to selectively detect Strep A antigen in a throat swab specimen.
The Strep A Rapid Test Cassette (Throat Swab) is a qualitative, lateral flow immunoassay for the detection of Strep A carbohydrate antigen in a throat swab. In this test, antibody specific to Strep A carbohydrate antigen is coated on the test line region of the test. After the test strip is immersed into a specimen, the extracted throat swab specimen reacts with an antibody to Strep A that is coated onto particles. This mixture migrates up the membrane to react with the antibody to Strep A on the membrane and generate a colored line in the test line region. The presence of this colored line in the test line region indicates a positive result, while its absence indicates a negative result. To serve as a procedural control, a colored line will always appear at the control line region, indicating that proper volume of specimen has been added and membrane wicking has occurred.
Strep A Reagent A (2M Sodium Nitrite)
Strep A Reagent B (0.4M Acetic Acid)
Materials Required But Not Provided
STORAGE AND STABILITY
Store as packaged in the sealed pouch at room temperature or refrigerated (2-30°C). The test strip is stable through the expiration date printed on the sealed pouch. The test strip must remain in the sealed pouch until use. DO NOT FREEZE. Do not use after the expiration date.
SPECIMEN COLLECTION AND PREPARATION
DIRECTIONS FOR USE
Allow the test device, specimen, reagents, and/or controls to reach room temperature (15-30°C) prior to testing.
1. Remove the test device from the sealed foil pouch and use it as soon as possible. Best results will be obtained if the test is performed immediately after opening the foil pouch.
2. Hold the Reagent A bottle vertically and add 4 full drops (approximately 240 uL) of Reagent A to an extraction test tube. Reagent A is red in color. Hold the Reagent B bottle vertically and add 4 full drops (approximately 160 uL) of Reagent B. Reagent B is colorless. Mix the solution by gently swirling the extraction test tube. The addition of Reagent B to Reagent A changes the color of the solution from red to yellow.
3. Immediately add the throat swab into the extraction test tube of yellow solution. Agitate the swab by rotating it at least 10 times. Leave the swab in the extraction test tube for 1 minute. Then express the liquid from the swab head by rolling the swab against the inside of the tube and squeezing the tube as the swab is withdrawn. Discard the swab.
4. Fit the dropper tip on top of the extraction test tube. Place the test device on a clean and level surface. Add 3 full drops of solution (approx. 100 μL) to the specimen well (S) and then start the timer.
5. Wait for the colored line(s) to appear. Read the result at 5 minutes. Do not read the result after 10 minutes...
INTERPRETATION OF RESULTS (Please refer to the illustration above)
POSITIVE: Two lines appear. One colored line should be in the control line region (C) and another apparent colored line should be in the test line region (T). A positive result indicates that Strep A antigen is detected in the specimen.
NEGATIVE: One colored line appears in the control line region (C). No line appears in the test line region (T). A negative result indicates that Strep A antigen is not present in the specimen, or is present below the detectable level of the test. The patient’s specimen should be cultured to confirm the absence of Strep A infection. If clinical symptoms are not consistent with results, obtain another specimen for culture.
INVALID: Control band fails to appear. Results from any test which has not produced a control band at the specified reading time must be discarded. Please review the procedure and repeat with a new test. If the problem persists, discontinue using the kit immediately and contact your local distributor.
NOTE: 1. The intensity of the color in the test line region (T) will vary depending on the concentration of Strep A antigen present in the specimen. Therefore, any shade of color in the test line region (T) should be considered positive.
2. Insufficient specimen volume, incorrect operation procedure, or performing expired tests are the most likely reasons for control band failure.
Internal Quality Control
Internal procedural controls are included in the test. A colored line appearing in the control line region (C) is an internal positive procedural control. It confirms sufficient specimen volume, adequate membrane wicking and correct procedural technique.
External Quality Control
In addition to your laboratory’s standard quality control procedures, it is recommended that a positive and negative external control be tested at least once within each test kit and by each operator performing testing within a kit. This will verify that the reagents and test strips are working properly and the operator is able to correctly perform the test procedure. External positive and negative controls are supplied in the kit.
Procedure for External Quality Control Testing
1. Add 4 full drops of Reagent A and 4 full drops of Reagent B into an extraction test tube. Mix the solution by gently swirling the extraction tube.
2. Add 1 full drop of positive or negative control solution into the extraction tube, holding the bottle vertically.
3. Place a clean swab into this extraction tube and agitate the swab in the solution by rotating it at least 10 times. Leave the swab in the extraction tube for 1 minute. Then express the liquid from the swab head by rolling the swab against the inside of the extraction tube and squeezing the extraction tube as the swab is withdrawn. Discard the swab.
4. Continue with Step 4 of Directions For Use.If the controls do not yield the expected results, do not use the test results. Repeat the test or contact your distributor.
1. The Strep A Rapid Test Cassette (Throat Swab) is for in vitro diagnostic use only. The test should be used for the detection of Strep A antigen in throat swab specimens only. Neither the quantitative value nor the rate of increase in Strep A antigen concentration can be determined by this qualitative test.
2. This test will only indicate the presence of Strep A antigen in the specimen from both viable and non-viable Group A Streptococcus bacteria.
3. A negative result must be confirmed by culture. A negative result may be obtained if the concentration of the Strep A antigen present in the throat swab is not adequate or is below the detectable level of the test.
4. The sterile swabs provided with this test must be used for specimen collection. Other swabs have not been validated with this test.
5. Excess blood or mucus on the swab specimen may interfere with test performance and may yield a false positive result. Avoid touching the tongue, cheeks, and teeth5 and any bleeding areas of the mouth with the swab when collecting specimens.
6. As with all diagnostic tests, all results must be interpreted together with other clinical information available to the physician.
Approximately 15% of pharyngitis in children ages 3 months to 5 years is caused by Group A beta-hemolytic Streptococcus. In school-aged children and adults, the incidence of Strep throat infection is about 40%. This disease usually occurs in the winter and early spring in temperate climates.
Table: Strep A Rapid Test vs. PCR Test
|Strep A Rapid Test||Results||Positive||Negative|
Relative Sensitivity: 94% (88%‐98%)* Relative Specificity: 98% (96%‐99%)*
Accuracy: 97% (96%‐98%)* * 95% Confidence Intervals
The following organisms were tested at 1.0 x 107 organisms per test and were all found to be negative when tested with the Strep A Rapid Test Cassette (Throat Swab). No mucoid-producing strains were tested.
|Group B Streptococcus||Bordetella pertussis||Corynebacterium diphtheria|
|Neisseria meningitidis||Streptococcus mutans||Streptococcus sanguis|
|Serratia marcescens||Group C Streptococcus||Hemophilus influenza|
|Group F Streptococcus||Neisseria gonorrhea||Candida albicans|
|Neisseria sicca||Staphylococcus aureus||Enterococcus faecalis|
|Klebsiella pneumoniae||Group G Streptococcus||Pseudomonas aeruginosa|
|Streptococcus pneumoniae||Neisseria subflava||Staphylococcus epidermidis|
Three physicians’ offices were used to conduct an evaluation of the Strep A Rapid Test Cassette (Throat Swab). Personnel with various educational backgrounds performed the testing. Each physician’s office tested a randomly coded panel of samples consisting of negative (20), low positive (20), and medium positive (20) specimens for three days. The results obtained had a 96% correlation with the expected results.
1. Murray, P.R., et al. Manual of Clinical Microbiology, 6th Edition, ASM Press, Washington D.C. p.?299-307.
2. Webb, KH. Does Culture Confirmation of High-sensitivity Rapid Streptococcal Tests Make Sense? A Medical Decision Analysis. Pediatrics (Feb 1998), 101:2, 2.
3. Bisno AL, Gerber MA, Gwaltney JM, Kaplan EL, Schwartz RH. Diagnosis and Management of Group A Streptococcal Pharyngitis. Clinical Infectious Diseases (1997), 25: 574-83.
4. Needham CA, McPherson KA, Webb KH. Streptococcal Pharyngitis: Impact of a High-sensitivity Antigen Test on Physician Outcome. Journal of Clinical Microbiology (Dec 1998), 36: 3468-3473.
5. Shea, Y.R., Specimen Collection and Transport, Clinical Microbiology Procedures Handbook, Isenberg, H.D., American Society of Microbiology, Washington D.C., 1.1.1-1.1.30, 1992.
6. Nussinovitch, M, Finkelstein Y, Amir J, Varsano, I. Group A beta-hemolytic streptococcal pharyngitis in preschool children aged 3 months to to 5 years. Clinical Pediatrics (June 1999), 38:?357-360.
Woods WA, Carter CT, Stack M, Connors Jr AF, Schlager TA. Group A Streptococcal Pharyngitis in Adults 30 to 65 years of age. Southern Medical Journal (May 1999), 491-492.7.
Span Biotech Ltd. is a research based company for rapid tests, with strong support from National Key Laboratory of Technology Projects of 10th and 11th Five-Year Plan and Faculty of Life Sciences of HuBei University. SpanBio also housed a R&D team that is developing gene recombination, cell cultivation and protein purification techniques. SpanBio pays strict attention on rapid tests for human being, animal diseases and food safety detection. It provides a number of customized services to professional distributors and partnering affiliates with excellent quality, competitive prices and super service.
Contact Person: Ms. Anna Lee