Procedure

BIOSTARâ ACCEAVA STREP A TEST

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Pathology Department	1
Emergency Department	1

PRECAUTION: WHILE PERFORMING THIS PROCEDURE, THE FOLLOWING

SAFETY MEASURES MUST BE TAKEN: GLOVES MUST BE WORN; SMOKING, EATING, DRINKING, APPLICATION OF COSMETICS, AND MANIPULATION OF CONTACT LENSES ARE PROHIBITED IN ALL TECHNICAL WORK AREAS. REFER TO THE UNIVERSAL PRECAUTIONS POLICIES.

CLIA Complexity: Waived-Definitive

I. Principle

This test uses color immunochromatographic technology with rabbit antibodies coated on the nitrocellulose membrane. In the test procedure, the throat swab is subjected to a chemical extraction of a carbohydrate antigen unique to Group A Streptococcus. The test stick is then placed in the extraction mixture and the mixture migrates along the membrane. If Group A Streptococcus is present in the sample, it will form a complex with the anti-Group A Streptococcus antibody conjugated color particles. The complex will then be bound by the anti-Group A Streptococcus capture antibody and a visible blue Test Line will appear to indicate a positive result.

II. Specimen

Collect the specimen with a sterile swab from the back of the throat and/or tonsils. Avoid teeth, gums, tongue, and cheek surfaces.

Acceptable swabs and media Unacceptable swabs and media

Rayon or Dacronâ swab Swabs with cotton tips

Swabs with transport tubes containing Swabs with wooden shafts

liquid media Calcium alginate swabs

Collection system containing

charcoal or semisolid transport media

Process the swab as soon as possible after collection of sample. If a culture result is required, streak the culture plate with the swab before starting the Acceavaâ Strep A Test procedure. Otherwise, the extraction reagents will cause the specimen to become nonviable.

The Acceavaâ Strep A Test does not require live organisms for processing. Therefore, the specimen swab may be stored and transported dry. If you do not perform the test immediately, store the swabs at room temperature or refrigerate the swabs for up to 24 hours. The swabs and the test kit must be at room temperature before you perform the test.

III. Materials and Reagents

Timer or stopwatch

Acceavaâ Strep A Test Kit

50 Test Sticks

50 Test Tubes

50 Sterile Swabs

1 Reagent #1- 2M Sodium Nitrite

1 Reagent #2- 0.3 M Acetic Acid

1 Positive Control- Nonviable Group A Streptococci, 0.1% Sodium Azide

1 Negative Control- Nonviable Group C Streptococci, 0.1% Sodium Azide

Test sticks and reagents must be stored tightly capped at 15°-30°C.

Do not use the test sticks or reagents after expiration date.

IV. Test Procedure

1. Collect the specimen with a sterile swab from the back of the throat and/or tonsils.

2. Just before testing, add 3 drops of Reagent #1 (pink) and 3 drops of Reagent #2 to the test tube (the solution should turn light yellow).

3. Immediately place the swab into the tube and thoroughly “mix and mash” by stirring and pinching swab through tube.

4. Let stand for 1 minute.

5. Express as much liquid as possible from the swab by squeezing the sides of the tube as the swab is withdrawn.

6. Discard the swab in a biohazard container.

7. Remove the test stick from the container (recap container immediately), and place the Absorbent End of the strip into the extracted sample.

8. Read results at 5 minutes. Positive results may be read as soon as the blue Test line and red Control line appears.

V. Results

A blue Test line and a red Control line is a positive result for the detection of Group A Streptococcus antigen.

NOTE: Any detection of the blue Test line should be interpreted as a positive result even if it has less color than the Control line.

A red Control line but no blue Test line is a presumptive negative result.

If after 10 minutes, no red Control line appears or background color makes reading the red Control line impossible, the result is invalid. If this occurs, repeat the test on a new Test Stick.

Results are to be documented in the patient’s chart and reported to the physician.

All negative results should be confirmed with a standard throat culture.

VI. Expected Results

Throat cultures from healthy individuals should not contain Group A Streptococcus antigen.

VII. Quality Control

Internal Quality Control

The Acceavaâ Strep A Test provides 3 levels of procedural controls with each test run.

C The color of the liquid changes from pink to light yellow as you add Extraction Reagent #2 to Extraction Reagent #1. This is an internal extraction reagent control. The color change means that you mixed the extraction reagents properly. The color change also means that the reagents are functioning properly.

C The red Control line is an internal control. The test strip must absorb the proper amount of sample and the test strip must be working properly for the red Control line to appear. For the test strip to be working properly, the capillary flow must occur.

C A clear background is an internal background negative control. If no interfering substances are in the specimen and the test strip is working properly, the background in the Control line area will clear. A discernible result will be seen.

If the red Control line does not appear, the test may be invalid. If the background does not clear and interferes with the test result, the test may be invalid. If this occurs, do not report the patient result. Call Biostar’s Technical Service at 1-800-637-3717 if you experience either of these problems.

External Quality Control

A positive and a negative external control must be tested when opening a new test kit, once within each 25 tests, and each operator performing testing within a test kit must test a positive and negative control with each 25 tests. The expected result for the positive control is positive and the negative result is negative. If this is not the case, the entire kit will not be used. All Quality Control results are to be documented on the Quality Control Logsheet.

VIII. Quality Control Procedure

1. Dispense 3 drops of Reagent #1 and 3 drops of Reagent #2 into test tube.

2. Vigorously mix the control contents. Add 1 free falling drop of control from dropper bottle.

3. Place a clean swab into the tube.

4. Continue as you would for a patient sample, as instructed in the TEST PROCEDURE (IV) section.

IX. Proficiency Testing

As an additional assurance of quality, proficiency testing samples will be distributed three times annually. These samples will be from the College of American Pathologists and distributed by the Pathology Department.

X. Competency Checks

Competency checks are performed during MYR yearly by the POCT Medical Technologist or a validated nurse.

XI. Limitations

C The results obtained from this kit yield data that must be used only as an adjunct to other information available to the physician. The Acceavaâ Strep A Test is a qualitative test for the detection of Group A Streptococcal antigen. This test does not differentiate between viable and nonviable Group A Streptococci.

C This test should be used only with throat swabs or colonies taken directly from a plate. The use of swab specimens taken from other sites or the use of other samples such as saliva, sputum, or urine has not been established.

C The quality of the test depends on the quality of the sample; proper throat swab specimens must be obtained.

C This test does not differentiate between carriers and acute infection. Pharyngitis may be caused by organisms other than Group A Streptococcus.

C A negative result may be obtained if the specimen is inadequate or antigen concentration is below the sensitivity of the test. A negative Acceavaâ Strep A Test should be followed up with testing using the culture method.

XII. References

Biostarâ Acceavaâ STREP A Test Package Insert, 1998