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Negative test 9 days post-Rifaximin

Posted: Wed Mar 06, 2019 12:56 am
by JMArnold
I’m a new member, and I’ve read the rules, etc. I’m female, 57 yrs old.

I have had a lot of trouble with dysbiosis/diarrhea over the last decade. I tested positive for SIBO, and used herbal-based antimicrobials to resolve the D, but relapsed repeatedly. 2018 was an especially bad year, and those herbal treatments quit working altogether.

In December, I did an Organic Acids test, which provides various markers — the marker for 4-Cresol (a byproduct of C diff) was elevated. I was having watery diarrhea several times a day (w/ strange smell & yellowish) — so my primary care doc and I agreed that the test result & symptoms were a strong indicator that I was dealing with C-diff. Also, S boulardii had been very helpful for me, and that seemed to be another indicator.

I had been planning to take Rifaxamin (commonly used for SIBO) — for the SIBO anyway. So I took a 14-day course of Rifaximin with some tapering/pulsing at the end, and it cleared the watery D in about 10 days. I felt so much better than I had in a long time. But about 4-5 days after the taper, the diarrhea returned.

In learning more about C-diff, I realized I really should be working with a GI doc, but I also knew they probably would not recognize the 4-Cresol marker as valid. I anticipated that a GI would want a more recognized C-diff test — and my primary doc had given me a lab slip for CD antigen/toxin testing.

The watery diarrhea after the Rifaximin was escalating quickly to many times a day, and I was getting quite concerned. I waited as long as I felt I could tolerate before running that antigen & toxin test — 9 days post-antibiotic.

The result was negative. Now I don’t know what to think. I did go back on the Rifaximin though, because that did resolve the D before.

Here’s my question: Might this negative test strongly indicate that I am not dealing with CD….or is there a possibility that I do have it? Could this be a false negative after the antibiotic? Could CD be causing all this D, without yet producing enough toxins / antigens (post-antibiotic), for the test to detect?

Re: Negative test 9 days post-Rifaximin

Posted: Wed Mar 06, 2019 8:42 am
by JMArnold
The testing method was EIA, by the way.

Re: Negative test 9 days post-Rifaximin

Posted: Wed Mar 06, 2019 9:54 am
by Musings
Guidelines state that you should not test until 14 days out from an antibiotic treatment as earlier may result in a false negative.

Re: Negative test 9 days post-Rifaximin

Posted: Wed Mar 06, 2019 10:54 am
by roy
If C.diff was causing D then it must follow that there's enough c.diff toxin to cause disease.
If theres enough toxin to cause disease then theres more than enough to be detected by testing.
The antigen part of the test is very accurate, no antigen means no recent c.diff.
Testing too early can result in false negatives but thats when you have no symptoms, test just before the c.diff is active and spores germinate after the test is done and D returns a short while later.

Rifaxamin is effective against around half of the c.diff ribotypes and only the less virulent ones.
I cant understand why your Dr did not order a true c.diff test before treating if they suspected c.diff.
Is this "Dr" a qualified medical practicioner?
The initial test you describe is not a c.diff test.

Re: Negative test 9 days post-Rifaximin

Posted: Wed Mar 06, 2019 11:55 pm
by JMArnold
OK, thank you both.

Re: Negative test 9 days post-Rifaximin

Posted: Sun Mar 10, 2019 9:13 pm
by Ril
I would advise that in light of the lack of any resolution and going outside usual protocols, you seek consulation with a GI dr as you were considering previously.