Re: Testing for H.Pylori

Posted By HFHSM.D.-jg on October 29, 1998 at 07:28:52:

In Reply to: Testing for H.Pylori  posted by Linda on October 23, 1998 at 09:30:39:






Last spring I had a positive biopsy for H. Pylori when I had an endoscopy performed.  I was treated for 10 days on antibiotics.  Recently, I developed similar symptoms.  My GI doctor wants to retest me using a new "investigational" test called "Helicobacter Pylori Stool Antigen".  The "investigational" part has really caught my curiosity.  Do you know anything about this test?  Can't I just have another blood test done?  Also, I thought once you were treated with antibiotics for H. Pylori..you shouldn't get it back again.  Is that true?  
_______
Dear Linda:
H. pylori is a cause of ulcer disease.  Eradication of the infection reduces the risk of  recurrent ulcers.  Whether it is necessary to treat patients with non-ulcer dyspepsia (epigastric pain but no ulcer found) is controversial because there is no convincing data that patients have decreased symptoms ( although specific subsets of patients with non-ulcer dyspepia may benefit from treatment).  There is , however, evidence that H. pylori infection is a risk factor for the development of gastric cancer.  This observation has resulted in many physicians treating patients with H. pylori infection even though they have not had an ulcer. There are many treatment regimens for H. pylori.  They have about the same efficacy, eradicating the bacteria in 85-90% of those treated.
There are three possibilities regarding your recurrent symptoms. 1) you belong to the subset patients who responded to the treatment for H. pylori, H. pylori was not eradicated due to bacterial resistance to the antibiotics or the treatment was not efficacious; 2) your H. pylori has been eradicated, but your symptoms might not caused by H. pylori infection; 3) reinfection with H. pylori.
How does one determine if a patient has eliminated H. pylori infection after treatment?  The Stool Helicobacter Pylori Antigen Test is a newly developed test for H. pylori.  It has gone beyond the "investigational" stage.  In fact, the test can be done in some laboratories, with high sensitivity (94%; means that 94% of those with the infection will have a positive test) and high specificity (96%; if you have a negative test then there is a 96% chance that you do not have the infection)  For patients with a prior H. pylori infection (as in your case), the serology test is not helpful.  Once you have been infected an ddeveloped antibodies to H. pylori, the antibodies remain forever, even if the infection has been cured.  A positive H. pylori blood test just means that you were once infected and does not necessarily mean that you are still infected.
The Breath 14C-urea Test is another nonivasive test to idebtify people with active H. pylori infection.  The test is based on the enzymes that are made by H. pylori .  this test is also highly sensitive and specific. Finally, the doctor can repeat the endoscopy and gastric biopsy .
This information is presented for educational purposes only.  Always ask specific questions to your personal physician.
HFHSm.D.-jg
*keywords: H. pylori, serology, tests
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