Thyroid UK
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Little random, but asking in the off chance anyone has taken Co-amoxiclav, and how long to wait afterwards before having blood tests please?

Hi, just wondering if anyone can help please. Have just had another 2 courses of antibiotics for recurring sinus and inner ear infections Amoxiccillin 250 mg, then Co-amoxiclav 509/125 mg and have been given a referral for the Active B12 test. Have contacted the hospital about this, they think the Active b12 results will be unaffected by recent antibiotics, but if I wanted to go ahead with MMA test that could possibly be affected, but no mention of how long I'd need to wait.

It does warn on the latter mess that white bloods can be reduced and red cell, glucose and liver test results affected.

Am very keen to get going with my long awaited Active test so would appreciate if anyone knows anything about it please?

Oh dear, it should say meds, not mess! Have corrected once but done it again, am still feeling pretty pooped, so am keeping everything crossed now I've just finished tabs that I don't need anymore!

Thank you any ideas greatly appreciated :)

2 Replies

Jo5454, I know it is possible to have some adverse effects two weeks after finishing a course of antibiotics. Perhaps you could wait 2-4 weeks after finishing the course before having the MMA test.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


Hi Clutter, thanks so much for your reply, sorry for the slow answer! I finished those antibiotics but still had symptoms and high temp, so on a third type now, fingers crossed for these ones! Have been trying to get rid of this for 6 months now, finally had a gap for 3 weeks, had a cold during that time, so would've been fine to do the tests, but was waiting to hear if I could have a referral. Oh well such is life the cold resulted back to infections, but at least I have the referral!

It doesn't seem as if the active b12 is affected by antibiotics so think I'll get on with that one and if it is low, have the other test later. Am wondering if my b12 at 261 on last testing is not helping me fight these persistent infections.

Thought I'd tell u the reply I had from the PA site, as I found it really interesting...

The old way of testing MMA used to be microbiological, measuring using bacteria so any antibiotic would kill off those bacteria ruining the test result.

The new way of testing ( gas chromatography- mass spectrometry) wouldn't be directly affected by antibiotics.

However...a lack of propionate formed in the gut may mean less MMA is produced. ( some propionic acid is formed by gut bacteria and may be affected by antibiotics, but it is also produced by the body as the end product of the breakdown of odd carbon fatty acids)

So the new way of testing would be accurate in terms of the testing stage, but accurately low if antibiotics have reduced this.

These sites are amazing aren't they, always people ready to help and share...

Thanks so much for yours..Jo :)

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