Rapid Strep A Using OSOM Strep A Effective Date 12/7/10
Document #10/version #03
Principle The OSOM Strep A uses color immunochromatographic dipstick technology with rabbit antibodies coated on the nitrocellulose membrane.
An extraction procedure is performed on a throat swab. A test stick is added to the extraction mixture and produces a visible blue test line if
Strep A is present.
Sample A sterile swab is used to collect a specimen from the back of the throat.
Teeth, gums, tongue, and cheek surfaces should be avoided. Collection swabs supplies with the kit are recommended. Live organisms are not required. The swab may be store dry at room temperature if needed without jeopardizing the test result.
Materials
Quality
Control
Equipment

NA
Reagents Supplies

OSOM Strep A kit

Timer or watch

PPE
Internal Controls- Procedural controls are provided with each test.

The color of the liquid changes from pink to light yellow after the extraction reagents are mixed. This color change means that the reagents were added properly and are functioning properly.

A clear background indicates that the test stick is working properly and no interfering substances are present in the specimen.
External Controls- Each kit contains positive and negative controls to be tested when each new kit is opened. Results are recorded on the Strep A
QC log sheet.
Quality
Control
Procedure
Step Action
1 Place 3 drops of reagent 1 into a test tube.
2
3
4
Place 3 drops of reagent 2 into the tube.
Vigorously mix the control contents.
5
Add 1 free falling drop of the appropriate control into the tube.
Place a clean swab into the tube. Rotate the swab 10 times in
6 the tube.
Continue with step 4 of the test procedure.
Columbus County Health Department Laboratory, Whiteville NC 28472
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Rapid Strep A Using OSOM Strep A Effective Date 12/7/10
Document #10/version #03
Test
Procedure
Step
1
Action
Add 3 drops of reagent 1 and 3 drops of reagent 2 into an
2 extraction tube.
Insert the patient swab and rotate 10 times vigorously. Leave the swab in the tube.
3
4
Set timer for 1 minute.
Express as much liquid as possible from the swab by squeezing the side of the tube as the swab is removed.
5
Discard the swab.
With arrows pointing down, place a test stick into the test
6
7 tube.
Set timer for 5 minutes
Read at 5 MINUTES. Test is invalid after 10 minutes.
Interpretation
Positive Result
Negative Result
A blue test line and a red control line appear.
Detectable Strep A antigen is present in the sample.
A red control line but no blue test line appears. No
Group A antigen was detected or the levels of the antigen is below the detection level of the assay.
Invalid Result No red control line appears or the background color makes reading the red control line impossible.
Result Reporting Log results on lab log and enter into EMR.
Expected Values Negative for Group A Strep.
Procedural
Notes

Specimens may be collected using Culturette
®
swabs with modified
Stuart’s transport media. Swabs from other suppliers have not been validated. Do not use swabs that have cotton tips or wooden shafts. Do not use calcium alginate swabs. Do not use a collection system that contains charcoal or semisolid transport media.

Process the swab as soon as possible after collecting the specimen.

Do not use the swab to streak a culture plate after performing the rapid test. The extraction reagents will cause the specimen to become nonviable.

Sodium Nitrite may be harmful if swallowed. Do not taste or swallow.
Wash thoroughly after handling.

Acetic Acid will cause skin and eye irritation. If the solution comes in contact with the skin or eyes, flush with large volumes of water.

A blue or red line that appears uneven in color density is still considered a valid line. In some cases, a trail of color may remain in the background.
Limitations
Columbus County Health Department Laboratory, Whiteville NC 28472
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Rapid Strep A Using OSOM Strep A Effective Date 12/7/10
Document #10/version #03

The quality of the test depends on the quality of the sample. Proper throat swab specimens must be obtained. False negative results can occur from inadequately collected specimens.

The OSOM Strep A test should be used only with throat swab specimens.
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.

This test does not differentiate between carriers and acute infection.

Pharyngitis may be caused by viral or bacterial pathogens other than
Group A Streptococcus.
References
 Manufacturer’s package insert for OSOM Strep A.
Related Documents

Policy #2, Specimen Rejection Policy.

Policy #14, EMR Policy.
Author
Approval
Signature
Karen H. Wall, BSMT (ASCP), Technical Consultant
_____________________________
Name
_____________
Date
Columbus County Health Department Laboratory, Whiteville NC 28472
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