Can anyone explain under what circumstances urine MMA tests might be conducted in preference to serum tests ?
I thought I read somewhere a long while ago that urine testing would give more accurate results, but now cannot find that particular research paper. I have papers that mention the existence of both methods, but not when one would be chosen over the other.
I have had six tests -always serum.
I haven't a research paper to refer to.
All i know is its often done with a creatine urine test .
The ratio of creatine to MMA gives an accurate indication of an early or shortage of b12 . As explained at tge time.
As Excreted in the urine .
How this compares to a serum test I'm not sure.
Perhaps they shoujd both be done?
Must be merits for both?
Need the scientists/ lab technicians or doctors for this i think.
My daughter had this at some stage.
Along with other tests.
It was a 24hr urine collection
I had 24hr urine test whilst in hospital, I dont know the result , as most of my results from different test were kept from me, even now years later it is impossible to get certain medical records (I wonder why ?)
I've just looked. There is sn article on
Journal of clinical medicine
Diagnostic performances of;
The above mma/ creatine
Can't find a way to post it on here
Perhaus someone else's csn if relevant
Difficult to find any comparisons between the two methods. I'm asking because someone asked me. I seem to remember reading that urine testing more accurate- but cannot find the source now and could be wrong.
Thanks to you both.
It does say in Sally Pacholok's book: 'According to Dr. Eric Norman of Norman Clinical Lab, Inc., MMA is 40 times more concentrated in the urine than in the blood, and the urinary MMA (uMMA) is the preferred test over the serum MMA. The urinary MMA can be helpful in ruling out B12 deficiency, especially since our current lower limit range for B12 deficiency is much too low (typically less than 200pg/ml). (See above.)
Pacholok, Sally M.; Stuart, Jeffrey J.. Could It Be B12?: An Epidemic of Misdiagnoses (pp. 11-12). Linden Publishing. Kindle Edition. '
but it also adds: 'However, after reviewing past and present literature as well as thousands of patients’ results over a ten year period, we believe it does not make sense to use the MMA test to identify B12 deficiency when the serum B12 can do the job in the majority of cases if doctors use an updated threshold (greater than 450pg/ml), along with a clinical exam. We often see symptomatic patients whose serum B12 is low or in the “gray zone” and whose MMA is normal—and these patient often respond well to B12 treatment. It would be dangerous not to treat these patients because their MMA is normal, or to wait for the MMA to become abnormal and the serum B12 to fall further—resulting in poor health or worse yet, permanent neurologic injury. Moreover, the serum MMA also has limitations and can cause false positives and false negatives. The specificity of these tests is debated.13, 14, 15 We have seen symptomatic patients denied treatment because their serum B12 was in the “gray zone” and their urinary MMA, serum MMA, and/or homocysteine (see next section) was normal, only for these patients to return many months later in worse shape and with tests showing deficiency. In addition, MMA values can be normal in B12-deficient patients receiving antibiotics, which can eradicate the intestinal flora needed to synthesize propionic acid.16'
Pacholok, Sally M.; Stuart, Jeffrey J.. Could It Be B12?: An Epidemic of Misdiagnoses (p. 12). Linden Publishing. Kindle Edition.
Thankyou, ktwing - looks as if Ms Pacholok may have been my source.
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