Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
Pathology Associates Of Lexington, P.A.
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        Helicobacter screening test, blood
      
Helicobacter pylori, adult antibody screen, qualitative, serum/plasma/whole-blood

The Quidel helicobacter "QuickVue"  test is a bed-side, office-lab style of kit test which is used as a screening test on adults presenting with complaints and symptoms suspicious for helicobacter gastritis. It is a systemic, global test (a biopsy is a focal, geographically localized test), and it gives a yes/no, positive/negative type of result...no quantitative result data. It positive, treatment is considered. If negative, other tests for helicobacter can be employed: quantitative serological tests, the urea breath test (UBT), the stool antigen test, or biopsy diagnosis on specimens obtained from the internal lining of your stomach by an EGD endoscopic procedure performed by your gastroenterologist. This EGD gives the most comprehensive diagnosis because it allows a potential additional diagnosis of all other causes of esophageal, gastric, or duodenal distress/disease should the complaints not be due to helicobacter.

Each test kit is prepackaged to test one patient. The sample is introduced into the kit. If helicobacter-specific IgG antibodies (Ab) are present in the patient's blood, they will attach to tiny (nearly microscopic) red reagent beads which are coated with helicobacter antigen (Ag) This red-bead-Ag-Ab complex is then trapped by a kit line coated with monoclonal reagent anti-human-IgG antibody. As more and more is trapped, a visible red line appears, indicating a positive test.

Our main serological lab (LML) uses an EIA technology for testing, & the notations below apply also to results by that method.

Situations having negative or undetected levels of Ab:

  • true negative test...no helicobacter infection (our group/LML did a small QA study 6/4/02 comparing IHC biopsy and EIA...there were no IHC pos. cases with neg. EIA)
  • a false  negative because an infection has not caused the antibody level to rise high enough to "trigger" a positive screening test.
  • a negative result because not enough sample was added to the test
  • a negative result because test was on whole blood in a patient with elevated blood hematocrit (too little Ab-containing plasma/serum)
  • a treated patient in whom the infestation has been completely eradicated (BUT: the value of this test is greatest when a pre-treatment serology was known to be definitely elevated and the post-treatment test is found to be "negative"). If it is still "positive", it does not necessarily indicate a persisting infestation...it can take the antibody levels as long as 3 years (46 months3) to fall to "negativity" after eradication of the bacteria. However, a negative result is strong evidence that the bacteria have been eliminated.

Causes of "positive",  Increased Values/Levels

  • Helicobacter pylori infection of the stomach lining which has generated an antibody level high enough to "trigger" the test.

  • the test can persist as "positive" as many as 3 years (46 months3) after successful treatment 

References:

1. The Quidel "QuickVue" test technical brochure 9/96.

2. The Helicobacter Foundation

3. Interpretation of Diagnostic Tests, Wallach, 2000, 7th Ed., pages 804-805.

Test Synonyms

Other names for this exact or approximate agent are:   

  • helicobacter screen
 
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