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Positive stool test, negative endoscopy, which test to trust?

Posted: Sat Mar 19, 2022 3:36 pm
by Toesocks
I am very confused with my diagnosis and would appreciate some insight.

I was diagnosed as HP positive through a stool test last year. However, I have already had stomach problems my entire life: duodenal ulcers at 6 and 10, severe cramping and pain in stomach, bloating, diarrhea, nausea, and reflux at night - it lasts for months to years, then goes away for months to years, then comes back and the cycle repeats. I'm 36. I had a gastroscopy at 10 and it was negative for HP, but they discovered low acid and metaplasia. About 4 years ago I had a breath test because I was complaining about these same problems, but it was negative. I also had my second gastroscopy then and the results for HP were also negative. I wondered why my stool test was positive now, so my doctor sent me for another gastroscopy which I had a month ago. The RUT showed a positive result after 30 minutes. But the culture and PCR tests were both negative. Stomach tissue had fibrosis and lymphocytes, so something is clearly going on. Yet they also said that there were some organisms on the stomach tissue sample that were suspicious of being HP, but they couldn't quite tell if they were actually HP.

What is going on?! With each test, I have more questions than answers. I don't want to take the treatment if I don't actually have HP because I'm already in poor health and antibiotics always leave me incapacitated. When I asked different doctors which test is more reliable, each gave me a different answer!

I am completely lost. Could it be possible I've had a low count of the bacteria all these years due to hypochloridia and metaplasia? I've read once that it could be the case, but there were no final conclusions. Would it be sensible to try a blood test to see if I have antibodies, so I'd know whether I've ever even had the bacteria or not? Or another breath test to see if it aligns with the positive stool or not? Or maybe I have a different Helicobacter that also produces urease?
It's terrifying how I can't trust modern medicine to provide me with clear answers about what's going on.

What would be the best thing to do here?

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Mon Mar 21, 2022 11:10 am
by Helico_expert
Let me try give you some background of H. pylori, hopefully that will explain some of the conflicting results you received.

H. pylori can break down urea to produce ammonia to neutralize the acid. However, the biggest trick is to control the ammonia production. When there is no acid, ammonia pipeline can be turned off. H. pylori doesnt want to create an environment too alkaline to live in. That is why, doctors will always ask you to stop PPI for a couple of weeks before doing the breath test. Because PPI will stop your acid secretion. Without acid secretion, H. pylori will turn off the ammonia production. With the urea not broken down, your breath test will always give you a negative result.

So when you are young, you were diagnosed with low acid and metaplasia. Perhaps that's the reason for your false negative breath test.

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One of the advantage of having acid in the stomach is to sterilise food that you eat. So you are less likely to get food poisoning from bad bacteria. In the situation when your stomach doesnt produce acid anymore (could be due to gastritis or PPI), other bacteria can start to grow in the stomach. Some bacteria also carry urease enzyme that can break down urea into ammonia, such as E. coli and proteus. But no other bacteria produce more urease than H. pylori. That is why the RUT will get positive result very quickly if there is H. pylori. Usually within 10-15 min, depending on the H. pylori load. Therefore, a positive result from RUT over 30 min can sometimes be suspicious.

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PCR is a very sensitive test. It is so sensitive because it can target even very small quantity of DNA. Because of this, false positive rate from PCR can sometimes be a problem. Assuming that the PCR test targets the right H. pylori gene, it's very difficult for PCR to give a false negative result.

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H. pylori culture is very skill dependant. Especially when a stomach is no longer acidic, many organism can grow. H. pylori is a very slow growing organism, which need at least 4-5 days to show up on agar plates. Other organism however show up on the agar over 24 hours. Therefore, after 4 days, the agar will be full of contamination and the technician will have to fish out H. pylori out of many. This can be a very challenging task. That's why culture success rate is usually very poor.

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When your stomach is no longer acidic, other bacteria can start growing. These bacteria usually produce some kind of anti-bacterial agents to compete with nutrients and their own survival. H. pylori is like a panda. The slow growing H. pylori cannot compete with the contaminants. H. pylori number can become very low and not detectable by many test, including PCR.

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What about serology? your doctor should ask for serology if they understand H. pylori and your situation. If you had H. pylori, your serology will be positive. even if you get rid of H. pylori, your body can still carry antibody for years. So a negative serology will tell you that you do not have H. pylori now and possibly free of H. pylori in the past few years.

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Thu Mar 24, 2022 1:58 am
by Toesocks
Thank you kindly for the detailed explanation! Very valuable information.

I'm definitely going to have a blood test done. And I think I'll do another breath test just in case. I'll report back with my findings.

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Sat May 21, 2022 3:01 pm
by Toesocks
Update: I had the urea breath test and the blood test last week. Both were negative.

I guess I can leave H. pylori behind now. Though I do still wonder what those other organisms they found in my biopsy, that supposedly looked like H. pylori, were. And if they may be the reason for my life-long gastritis. Not sure I'll ever find out at this point ...

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Sun May 22, 2022 2:30 am
by Krs
hey toesocks,

coincidentally I looked on the website and saw your forum, I also have long-term stomach problems and 5 years ago I was treated against the h.pylori. but I have had complaints again since 2 months, vague pain in the upper abdomen. have a stool test done in April. was negative.. Do you also have long-term stomach complaints? and what for?

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Sun May 22, 2022 3:01 pm
by Toesocks
I've described it in my first post what my problems are. I was never treated for H. pylori.

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Sun May 22, 2022 5:19 pm
by Krs
do you still have stomach problems and present every day?

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Sun May 22, 2022 11:12 pm
by Toesocks
Yes, unfortunately. I'll be going back to the doctor for more exams, but don't have my hopes up.

Re: Positive stool test, negative endoscopy, which test to trust?

Posted: Mon May 23, 2022 1:09 am
by Krs
Jaa When was the last time you had a stomach exam? Are your symptoms less or gone after you have eaten?