The reason why the patient has to be seated after lying down is to allow the labelled carbon dioxide (produced as a result of the presence of H. pylori) to move up to the lungs for breathing out into the bag. (answered gail, shu hui and vino)
Is there anything in the bag and how the breath bag is sent to the lab? Will results be inaccurate if the breath bag is exposed to the surrounding air?
The breath bag is a sterile bag which contain no anticoagulant. There is no special procedure that must be followed during the sending of bag to the lab. Once patient breathes out into the bag, it must be capped immediately. Of course results will be inaccurate if the patient does not capped the bags properly, therefore the bags will be sealed in another big plastic bag when sent to the lab. As this test is usually conducted in the hospital, the breath bag will be sent immediately up to the lab for processing. The processing and sample handling part is less complicated. However, the med techs do act fast when they are processing the samples. For example, when they remove cap on the breath bag, they will quickly fit the mouth of the breath bag to the machine. In another words, they will try to lessen the exposure of the breath inside the bag to the surrounding air .The tedious part will have to be sample collection. (answered ci liang, martin and liu qian)
Why patient cannot chew the tablet?
Because chewing may reduce the actual amount of the tablet that goes into the stomach and results can be inaccurate. Patient's result may be negative when actually very little tablet is present in the stomach, more of it is remained on the patient's teeth. (answered Kangting)
Why not do a culture for the detection of the microorganism?
This is a good question. Yes, biopsy check during endoscopy with a rapid urease test, histological examination and microbial culture are much better and relaible choice for the detection of the microorganism. In fact, histological examination is the gold standard for the detection of H. pylori. But seriously thinking, all the above three methods are evasive. Let's say if a patient is under treatment and doctor want to see the effectiveness of the treatment, do you think the patient will like it if he has to do endoscopy every now and then. It will be uncomfortable to the patient. Therefore, with UBT, patient's treatment progress can be updated and he does not have to undergo any evasive procedure.
This is also the advantage of UBT. UBT is the gold standard for the determination of treatment process. (answered jia hao)
Additional info:
Disadvantage of UBT is that it is subjected to non-conformance by patient as there are many instructions that must be followed before taking the test.
They are:
- Fast for 8-9 hrs before test because food can interfere with results
- Stop taking Proton Pump Inhibitors (PPI) eg. omeprazole, lansoprazole one week before the test because they are acid-reducing medication which can cause the stomach condition to become less acidic. This is no good for the thriving of H. pylori. Helicobacter spp. are the only known microorganisms that can thrive in the highly acidic environment of the stomach.
- Stop taking antibiotics eg amoxicillin, tetracycline 4 weeks before test. This test measures active H. pylori infection. If antibiotics are suppressing the amount of H. pylori present in the stomach, results will not be accurate too.
Sally
2 comments:
Hihi,
My lab tests for H.pylori using the serologic method. We use an immunoenzymatic assay that detects the h.pylori IgG antibodies against the commercial antigens. It is non invasive and cheap to perform. So, may i ask, in your opinion, is there any advantages of the breath bag method over the serological method?
And lastly, lets say that chewing or dissolving the tablet in the mouth would reduce the effectivity of the tablet, would taking water help maintain the efficiency if the patient chews or dissolves the tablet in the mouth because water would rinse the tablet remnents down to the stomach........
I hope my question is not superficial or stupid....
Tnks
Yeng Ting
Tg02
firstly, address to all, my helicobacter pic is taken from http://www.gastroenterologe.de/patient/erkrankungen/magen/helicobacter_inf.html.
Back to ur question, i think u mean using patient's serum to detect the presence of specific antibodies. yes, in my opinion i think maybe the serological methods is better cos i noe teh UBT involves alot of procedures n it may subject to patient's or the nurse's manipulation n results will be inaccurate. i'm not sure urs got any limitations or not.
and lastly, there are some patients who can't swallow tablet so what the protoccol suggests is that we can dissolve the tablet in warm water and let the patient drink it. After that he/she has to gargle 2 to 3 times to ensure all amount goes into the stomach. Thanks for ur comment
sally
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