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     One Step Group A Streptococcus Test 

INTRODUCTION TO Test Strep A

Group A Streptococcus is a principal cause of upper respiratory infections such as tonsillitis, pharyngitis, and scarlet fever.  Since pharyngitis can lead to rheumatic fever or acute glomerulonephritis, it is important to differentiate streptococcal pharyngitis from viral diseases during early infections.  The Strep A Rapid Test is a simple and rapid test which can detect Group A Streptococcal antigen directly from throat swabs or culture plate which allow physicians to diagnose and administer therapy immediately.

REAGENTS AND MATERIALS PROVIDED

1.     Testing Device, 50 pcs. Individually sealed in foil pouches.  Each pouch contains a sample dropper.

2.     Reagent A, 1x8ml, 1M Sodium Nitrate.

3.     Reagent B, 1x8ml, 1M Acetic Acid.

4.     Reagent C, 1x8ml, 1.5 M Tris Buffer.

5.     Positive Control, 1x1ml, Extracted Antigens of Strep A with Sodium Azide.  (optional)

6.     Negative Control, 1x1ml, Extracted Antigens of Strep B with Sodium Azide.  (optional)

     EQUIPMENT REQUIRED BUT NOT PROVIDED

     Clock or timer.

STORAGE CONDITIONS

The Strep A Rapid Test including all reagents can be stored at room temperature or refrigerated (2-28°C).

SPECIMEN COLLECTION AND STORAGE

A specimen should be collected by standard throat swab collection methods.  It is preferable to use Dacron-tipped sterile swabs with plastic shafts.  Swabs should be processed as soon as possible after collection.  If swabs are not processed immediately, they should be placed into a sterile, dry, tightly capped tube or bottle.  Swabs which have been transported in liquid media, such as modified Stuart’s Transport Medium, may be used in the test provided.   The liquid medium is 1 ml or less.  Do not use calcium alginate or wooden shafted swabs.  Do not use semi-solid transport media or media containing charcoal.

Specimen swabs may be stored refrigerated (2-8°C) for up to 5 days.

PERFORMING THE TEST

If specimen, control, or reagents have been stored in the refrigerator, allow all specimens and reagents to warm to room temperature (18-25°C) before testing.  All drops must be free-falling with the reagent bottles held vertically.  In order to avoid contamination of reagents, do not allow the tips of the bottles to come in contact with the extraction cups.  The Positive Control and Negative Control are provided in order to monitor the integrity of the reagents and assure that the test procedure has been performed correctly.

 EXTRACTION

     1.   Place the specimen swab into the extraction tube.  Add 3 drops of Reagent A followed with 3 drops of Reagent B into extraction tube.  Mix contents well with the swab and let stand for 1 minute, but no longer than 10 minutes.

    2.   Add 3 drops of Reagent C to extraction tube.  Use swab to mix.  Remove liquid from the swab by pinching the rim of the extraction tube between thumb and finger and       gently removing the swab from the tube.

    3.   The extraction mixture can be tested immediately or at any time within the following 24 hours.

ASSAY TEST PROCEDURE 

1.   Bring up all reagents and specimens to room temperature.

2.    Label the device with specimen identification.

3.   Add 3 drops from the extraction tube to the sample well marked “S”.

4.   Read the result within 5 minutes, do not interpret result after 10 minutes.

 

 

The test results should not be interpreted after more than ten minutes. To avoid confusion, read the result at ten minutes and discard the Testing Device.

       NOTE: A difference in intensity may occur between the lines in the test region (T) and control region (C) but this does not affect the interpretation of the results.

INTERPRETATION OF RESULTS

POSITIVE: Two pink colored bands appear, one in the control region (C) and one in the test region (T), indicating a positive result and that the sample contains Streptococcal Group A antigen.

NEGATIVE: Only one pink colored band appear on the control region (C), the result is negative for Streptococcal Group A antigen.

INVALID: If no bands appear, or a test band appears without a control band, the test should be repeated using a new device.

　

 

                    　

          LIMITATION

1.      The Strep A Rapid Test is designed for use with throat swabs or colonies taken from culture plates.

2.      The test does not differentiate between carriers and infected individuals.  Pharyngitis may be caused by other organisms beside Group A Streptococci.

3.      Negative results may be obtained when the amount of extracted antigen is below the sensitivity of the test.  False negatives may result from improperly taken specimens.

4.      Additional follow-up testing using the culture method is required if the test result is negative and clinical symptoms persist.

5.      A test result read after 10 minutes may not be consistent with the original reading obtained within a 5 minute test period.