QUICKVUEFLEX STREP A TEST

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QUICKVUEFLEXSTREP A TEST
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INTENDED USE

• The QuickVue Flex Strep A Test allows for the
  rapid detection of group A streptococcal antigen
  directly from the patient throat swab specimens.
  The test is intended for use as an aid in the
  diagnosis of group A streptococcal infection.

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BACKGROUND

• Group A beta-hemolytic streptococci
  (Streptococcus pyogenes) is one of the most
  commonly encountered pathogens in humans.

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BACKGROUND (cont.)

• Group A Streptococcus inhabits the skin and upper
  respiratory tract of humans but is rarely
  considered as normal flora. It is transmitted
  person to person by direct contact with mucosa,
  secretions or by contamination droplets produced
  by coughs or sneezes. The presence of Group A
  Streptococcus is almost always considered
  clinically significant.

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BACKGROUND (cont.)

• When present, Group A Streptococcus can cause a
  variety of illnesses. It is the most common
  cause of skin infections such as impetigo and
  erysipelas. It can cause illness such as
  tonsillitis, pharyngitis, and scarlet fever which
  can lead to more serious complications including
  rheumatic fever and acute glomerulonephritis.

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BACKGROUND (cont.)

• Group A Streptococcus has also been called
  flesh eating bacteria because of its ability to
  progress into deeper tissue and organs which can
  cause systemic and life threatening infections.

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BACKGROUND (cont.)

• Early diagnosis and treatment of Group A
  Streptococcus infections is therefore very
  important and helps to prevent further
  complications of many of the previously mentioned
  illnesses. The QUICKVUE FLEX Strep A Test is a
  rapid screening test used for the detection
  consumes little time when compared with the 24-48
  hours waiting period of more conventional methods
  that require microscopic examination, culture,
  and isolation of the bacteria.

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PRINCIPLES OF THE TEST

• THE QUICKVUE FLEX Strep A Test is a lateral-flow
  immunoassay. The test, containing a highly
  specific and sensitive antibody reactive to the
  Strep A antigens, is specific to Group A. To
  perform the test, a throat swab specimen is
  collected. The extraction reagents are mixed in
  a tube, resulting in a green color change, and
  the swab is added in order for the antigenic
  component of the bacteria to be extracted.

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PRINCIPLES OF THE TEST (cont.)

• Extraction occurs within one minute, after which
  the extracted sample is added to the Sample Well
  of the Test Cassette. The extracted sample
  migrates by capillary action through a pad
  consisting of a pink label containing rabbit
  polyclonal anti-strep A antibody and a blue
  control label. If the extracted solution
  contains strep A antigen, the antigen will bind
  to the antibody coupled to the pink test label
  which, in turn, will bind a second rabbit
  polyclonal anti strep A antibody spotted on the
  membrane, resulting in the formation of a
  pink-to-purple Test line.

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PRINCIPLES OF THE TEST (cont.)

• A 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 properly
  functioning Test Cassette. If strep A is not
  present or present at very low levels, only a
  blue Control Line will be visible.

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REAGENTS MATERIALS

• Come in individually packaged Test Cassettes
• Rabbit polyclonal antibody to strep A (Test
  Line) and a control rabbit polyclonal antibody
  capable of binding the blue control label
  (Control Line)
• EXTRACTION REAGENT A
• ( 4M Sodium Nitrite)
• EXTRACTION REAGENT B
• (.2M Acetic Acid)
• Sterile rayon-tipped swabs on solid plastic
  shafts
• Tubes and tips
• Positive Control Swabs
• Negative Control Swabs
• Package Insert
• Procedure Card

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TEST PROCEDURE

• Streak a BAP prior to beginning the extraction
  procedure.
• For each specimen and control
• Add 4 drops of Extraction Reagent A into a clean
  Tube
• Add 4 drops of Extraction Reagent B. The
  solution should turn green when Extraction
  Reagent B is added.

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PROCEDURE, cont.

• Immediately add the throat swab specimen to the
  Tube containing the green extraction solution.
• Rotate the swab three times.
• Wait one minute.

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PROCEDURE, cont.

• Express all liquid from the swab head in the Tube
  by rolling the swab against the inside of the
  Tube and squeezing firmly as it is withdrawn.
• Discard the swab.

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PROCEDURE, cont.

• Put a clean tip on the Tube.

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PROCEDURE, cont.

• Remove Test Cassette from foil pouch and place on
  a clean, dry surface.
• Add 2 drops from the Tube to the round Sample
  Well on the Test Cassette.

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PROCEDURE, cont.

• Read results at 5 minutes. Some positive results
  may be seen earlier, but negative results must be
  held the entire 5 minutes and no longer.

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INTERPRETATION OF RESULTS

• Positive results appearance of any pink to
  purple Test Line next to the T in the result
  window.
• Positive QuickVue Flex Strep A Test result
  indicates that the specimen contains group A
  streptococcal antigen.

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INTERPRETATION OF RESULTS (cont.)

• Negative Result Only the blue Control Line
  appears next to the letter C in the Result
  Window.

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INTERPRETATION OF RESULTS (cont.)

• A negative QuickVue Flex Strep A Test result
  indicates that the specimen is a presumptive
  negative for the presence of group A
  streptococcal antigen, pending the result of the
  BAP streaked prior to the beginning of the
  extraction procedure.

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INVALID RESULT

• The test result is invalid if any shade of blue
  Control Line next to the letter C is not
  visible at 5 minutes. If this occurs, retest
  using a new specimen and a new Test Cassette.

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PROCEDURE LIMITATIONS

• This procedure used for qualitative detection of
  group A streptococcal antigen from throat swab
  specimen only. Failure to follow the test
  procedure and interpretation of test results may
  adversely affect performance and /or produce
  invalid results.

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PROCEDURE LIMITATIONS

• QuickVue Flex Strep A Test will not differentiate
  asymptomatic carriers of group A Streptococcus
  from those exhibiting streptococcal infection.
  In rare cases, test specimens heavily colonized
  with Staphylococcus aureus can yield false
  positive results.

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PROCEDURE LIMITATIONS

• A negative test result might occur if the level
  of extracted antigen in a sample is below the
  sensitivity of the test. Additional follow-up
  testing using the culture method is recommended
  if the QuickVue test result is negative.

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CONCLUSION

• QUICKVUE FLEX TEST
• Is a rapid, specific and sensitive test for
  detection of Group A Streptococcus (
  Streptococcus pyogenes) antigen directly from
  patient throat swab specimen.
• It allows the physician to do quick diagnoses
  based on the results.
• It avoids the 24-48 hours incubation time for
  blood culture plate tests.
• This test is much more expensive than blood agar.