It will have new reference ranges which are higher, meaning more people will be 'positive'.
A Community Campaign led by Karen possibly helped 'focus minds'.
No news yet of other NHS labs starting to offer the test.
a GP or physician referral is essential, but our laboratory can offer advice by telephone or email on how to start the process
Sheffield CH website
The SCH has been the sole UK/Eire TMAU urine tester for many years (circa 1997). Last Autumn the test was suspended. A concern was that since the founder of the test (Nigel Manning) was retiring, that it may not return. Possibly these concerns were unfounded.
Testing Machine : Gas Chromatography
They will continue to use Gas Chromatography. Probably a legacy thing, as GC was the norm in 1997 and that is where their history lies for this test (and probably the machine).
Nowadays, if a lab was starting from scratch for a TMAU urine test, it would probably be based on Liquid Chromatography.
TMA: < 7.7 µmol/mmol creatinine
TMANO: < 119µmol/mmol creatinine
% N-oxidation: > 90-94%
Comment on the new reference ranges :
TMA 'normal cut-off point' is lower, meaning probably more TMA-overload positives (TMAU2). We have no comment on this, as it's not something we have info to compare to.
TMAO cut-off: Sheffield give a ref range for TMAO. In theory it would not seem relevant, but it does gives info. Example, if it's very high it means the person is producing a lot of gut TMA, but they can at least oxidize it.
Sheffield used to give this as a ratio, whereas all the other labs give it as a %.
A % is easier to understand (compare with other labs without need for arithmetic conversion), so this change is welcome
A major change that will greatly increase the TMAU1 positives is the new 'normal cut-off' point at around 90-94%. It used to be around 79%.
This seems much more in line with other labs and FMO3 papers, so is very welcome. The old cut-off point was too conservative.
On why they changed the reference ranges :
They are from the literature and the same that Heidleburg use and we have validated them with donated samples from the laboratory staff. We are still collecting data and hope to publish our own in the future. We have informed the laboratories and the clinicians that use our service that we are back in action so hopefully they will start to see patients again now.
Other NHS Labs to offer the test ?
During the discussion, there was talk of one or 2 other UK NHS biochemistry labs considering to start offering the TMAU urine test. Historically TMAU is seen as a 'very rare' condition and probably 'the poor relation' of rare disorders. In truth, when you add 'outliers' and TMAU2's, it could be quite common. In a small paper in the 1980's with about 400 students tested, about 3.8% were under 90% TMAO output, which back then would be within the normal range if above 80%. Nowadays that might make them borderline/transient/officially TMAU.
Rumor was that Bristol and Newcastle and perhaps a London NHS hospital were considering the test, but as of yet there is no news. It seems the network of NHS Biochemistry labs for Adult Metabolism Units can set their own rules on this test. So it may be looking more pessimistic but we will try to follow up.
The network of relevant NHS Biochemistry labs are known as METBIO
Karen's Campaign to have the test reinstated
TMAU tests at other labs have been scrapped in the past. It was feared this would happen with Sheffield. But whatever, a campaign to notify politicians and relevant agencies was begun, and it probably helped focus minds. Certainly it seems the politicians and agencies inquired about it. Hopefully it is an example of TMAU community power.
So overall, a problem has had a positive outcome.
Quotes from the lab
We are pleased to announce that Trimethylaminuria (TMAU) testing will recommence on Monday 13th February.
We are able to start receiving samples any time from now. All samples sent before the temporary suspension will be tested shortly.
Thank you for your patience while we resolved the technical issues related to this test.
The sample volume and requirements are as previous (20ml random urine acidified to pH2 with HCl or 24 hour urine in HCl sent by first class post). However, the method has been significantly modified from the previous method and subsequently the old reference ranges are invalid. The new reference ranges will be:
TMA: < 7.7 µmol/mmol creatinine
TMANO: < 119µmol/mmol creatinine
% N-oxidation: > 90-94%
They are from the literature and the same that Heidleburg use and we have validated them with donated samples from the laboratory staff. We are still collecting data and hope to publish our own in the future. We have informed the laboratories and the clinicians that use our service that we are back in action so hopefully they will start to see patients again now.
*********
You recently asked to be contacted when the Trimethylaminuria (TMAU) testing service provided by Sheffield Children's NHS Foundation Trust was restored. We are pleased to announce that testing will recommence on Monday 13 February.
We are able to start receiving samples any time from now. All samples sent before the temporary suspension will be tested shortly.
Please note that a GP or physician referral is essential, but our laboratory can offer advice by telephone or email on how to start the process.
Further information about the test is available on our website: http://www.sheffieldchildrens.nhs.uk/our-services/laboratory-medicine?tab=4
Thank you for your patience while we resolved the technical issues related to this service.
2 comments:
My conversion number was 84%. This number is considered within the normal range with Colrado labs with Dr Fennesey. So with this new adjustment I now would be officially positive for TMAU.
that's right.
one good thing is people can compare their results retrospectively.
That said, there are benefits in getting a new real result.
e.g. In the UK it can mean being referred to be under the auspices of an adult metabolism unit.