TMAU urine and dna test : doing both tests gives the clearest picture

The following is posted only to promote discussion
It should not be regarded as advice

summary:

• If you test for TMAU, its best to do both the urine and the DNA test
• Some have conflicting results: urine-fail/dna-normal, or urine-normal/dna fail
• While some FMO3 dna mutants are common and widely accepted, its likely there are many more mutants yet to be classified
• The accuracy of the urine test for tma/tmao is without question. The likelihood of false negatives may be questioned by some.

There are 2 tests to 'confirm as much as possible' the diagnosis of 'primary TMAU': the phenotype test (the urine test), and the genotype test (the DNA test). If someone chooses to test for TMAU, it probably makes most sense to do both tests. Some reasons are listed below:

On the forums, there have been anecdotal examples of one or two testing positive for primary TMAU in urine, but went on to not have any of the current DNA mutants in the DNA test. There have also been examples of the opposite, not failing the urine test, but having mutants in the DNA test. It must be understood that there are very few researchers in TMAU and even very few in FMO3 research (since it is perceived as a lesser important oxidizing enzyme. Pubmed paper).

Although the DNA test has been around for maybe 10 years, it is probably expected that many more mutants or other types of 'sensitive/polymorphic' fmo3 enzymes are yet to be discovered. The only known publically viewable list (online) of FMO3 'mutants/variants' seems to be a voluntary project by one or 2 TMAU experts in the UK. The website layout looks rather old-fashioned. Whether the list is up to date with recent research is not clear. It was last updated in 2006 (The FMO3 allelic variant database).

In the UK, 'secondary TMAU' seems to be tested for, whereas it's unclear if it is tested for elsewhere. There are other inconsistencies in testing procedures worldwide. In Australia, the 'tester' seems to not use the choline challenge test, but instead advises them to eat provoking foods the night before (fish and eggs). There also seems to be differences in the % mark set for fails. At the moment there does not seem to be a universal testing standard for the urine test to be followed by all testers.

In the USA, perhaps some over a certain age of developing bloodborne body odor/halitosis may be discouraged from testing, and so are lost in stats of the overall picture. It seems from the forums, that some in this category who go on to test, do fail the urine test. So perhaps it is worthwhile testing if some feel they may have TMAU and have been discouraged from testing.

It must be assumed that someone is keeping stats on TMAU testing, but it would seem the sufferers having access to the (anonymous) stats and perhaps control of them is the best way forward for the group, since they are likely the most motivated and concerned.

The main point is, neither test can be deemed conclusive, and even both tests can't be totally relied on as conclusive (moreso for 'false negatives'), but if you are going to do TMAU testing, both tests give the clearest picture, and perhaps if there are inconsistencies it will lead to more awareness and research into why some don't seem to fit the TMAU definition.

So if anyone chooses to test for TMAU, it is probably wisest to do both tests to get as much current info on your situation as possible. Also, if you have done one or most tests and did not feel the result(s) conclusive (most likely if you feel you have TMAU but the urine test said you don't) , you could possibly try the TMA-challenge urine test (the carrier test). This would only make sense if not enough TMA/TMAO was in your 'choline test' urine result. If there was enough TMA/TMAO, then your FMO3 enzyme got well tested by a TMA load. However, it seems that no expert will say TMAU is anything other than 'fish body odor', so perhaps the full picture of something like fecal body odor is yet to be defined.