| Helicobacter screening
Helicobacter pylori, adult antibody screen,
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
- 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
the test can persist as "positive" as
many as 3 years (46 months3) after successful
1. The Quidel "QuickVue" test technical
2. The Helicobacter
3. Interpretation of Diagnostic Tests,
Wallach, 2000, 7th Ed., pages 804-805.
Other names for this exact or approximate agent are:
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