Question of results of my 14C UBT

[rifle_li]

I have finished my eradication course in October last year. After that, I did 14C UBT for 3 times in same hospital. All three results are negative. But the DPM value is gradually increased. Results of my UBT are as follows:

2011-12-13 DPM=32
2012-01-28 DPM=45
2012-04-27 DPM=68

I am confused about these DPM values. Do these results indicate that H.pylori is growing slowly in my stomach? Thank you!

[Helico_expert]

what is the cut off value for your test? nevertheless, i think 3 datapoints are not enough. But I wouldnt worry too much as the duration for the increment seems a bit too long.

[rifle_li]

The cut off value of my test is 100. According the trend of my test results, maybe several months later I will get a positive again. Could that happen? Thank you!

[Helico_expert]

it is possible. if your HP was not successfully eradicated previously, your UBT reading will come back up after several months. But it has already been several months. So I think your chance is very low. I think it'll maintain around there. You eating anything (eg. pro-biotic) at the moment that may give it a false positive result?

[rifle_li]

Thank you, Helico_expert. I feel better after read your reply.
I did not eat probiotics or something when I had my test. Can probiotics(like yoghourt) give a false positive result of UBT?
Could you explain to me how the cut off value of UBT is defined? For example, we assume the cut off value is 100. one people get 99, he is negative. The other people who get 101 is positive. But what is the different between 99 and 101? I can not understand. Thank you again!

[Helico_expert]

Different companies of the UBT probably did a pilot study on normal people without H. pylori and get the average breath test value. That will be used as the cut-off value.

for those with a result very close to the cut-off value, we called it border line reading. these patients are usually asked for a repeat breath test after a few months. The true positive patients we have usually have a breath test value over 800-4000.

Urea breath test measures how much urea is broken down in a given 10 min period. H. pylori is not the only organism that has the ability to break down urea. But H. pylori has the most efficient urea breaking down enzyme.

other organism in your mouth will have the potential of breaking down urea. sometimes, they were swallowed together with saliva and stay in the stomach for and survive for some time (for how long, I dont know). They will be the reason for the low urea breath test count.

[rifle_li]

Thank you! Your reply is very detailed and useful.

[rifle_li]

I went to hospital and had a 14C UBT again today. The result is negative. The DPM value is 47. Just like Helico_expert said, the DPM becomes stable. One year past since I finished my eradication course. Maybe I can say bye-bye to Mr H.pylori now. I am so happy and want to thank Helico_expert again!