LAB LIST FOR TESTS RELATED TO NEUROPATHY CAUSED BY VITAMINS
Would anyone like a lab list for these problems? I collected a first few things here. If you have additions, send me some and I put them into this post, so we have it all in one place.
I will keep updating this list. currently there are gaps - as you can see.
Labs
GPL - Great Plains Labs, USA
- they are well prepared for receiving samples from allover the world. the urine is usable for up to 3 days shipping which allows sending by normal fedex international priority from anywhere. in addition, they have direct flights from many cities of the world. this means 24h shipment at no additional charge. fedex will tell you if your city or any city nearby has this. I was lucky and they got my sample in 24h to GPL.
- their OAT (urinary organic acid test)
http://www.greatplainslaboratory.com/organic-acids-test/
costs 346 USD incl shipment from Europe + some 50 or so USD shipment of testkit to Europe. it features a huge number of items, among others
quinolinic acid and 5hiaa
Ganzimmun, Mainz, Germany
- they are well prepared for sending in samples from allover Europe. in many countries they even have testing centers and collaborating doctors.
- their urinary
kynurenine & tryptophan test panel features also
quinolinic acid ("chinolinsäure") and 5hiaa. it costs 100 Euros. + a few years ago when I got tested, the shipment was some 50 Euro across Europe
http://www.ganzimmun.de/seiten/test.php?tab=1&test_id=1435
Prof Plecko, Kinderspital Zürich, Switzerland
- they are leaders in testing and treatment of
inborn errors of B6 metabolism. Their trick is: they test for all the many less known B6 vitamers in blood and from that they can infer what kind of B6 metabolic defect a patient has:
https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0034-1390552
- see below in the lab tests.
Spectracell
- test for
vitamins in wbc:
http://www.spectracell.com/clinicians/products/mnt/
- cost: 390 USD + some 120 or so Euros shipment from Europe
- stupidly, they do not give you their fedex number, which would allow for cheap rates. you have to pay full fedex rates. jerks.
- the test is only valid if it reaches Spectracell within 24h. So if sending from Europe, you must send it off from a city that has a direct fedex flight. this will deliver within 24h, at normal international priority rates
- for details on why to test, validity, etc, see below in the lab test list.
Lab tests
quinolinic acid.
!!! insert dannybex reference!!!
while the total value of quinolinic acid will be what causes neurotoxicity, I find the urinary quinolinic acid : 5hiaa ratio useful in finding pathology.
kynurenine : tryptophan ratio ( in urine??? ). this is the established scientific measure to determine if the kynurenine pathway is excessively activated. This is the pathway that produces among others quinolinic acid.
!!! diagramm !!!
B6:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4199287/#R34
"Vitamin B6 deficiency can be detected by direct assay of blood or urine. Pyridoxal phosphate can also be measured in the blood. Nerve conduction studies reveal severely reduced sensory nerve action potentials with preserved CMAP. Sural nerve biopsy confirms axonal degeneration of small and large myelinated fibers."
there are many functional markers for vitamins. it would make a lot of sense to me to measure them, as imbalances in other vitamins could cause b6 related neurotoxicity. these functional tests measure not what is just in the moment swimming around in the blood, but what is really available to metabolism.
open question: For most of these its a challenge to find a lab. if you know a lab, please send me!
see the attachments to this post for the list.
urinary vitamin testing:
for the same reason as mentioned above, one could measure urinary vitamin excretion. at least for water soluble vitamins this should make sense. I dont think the body pees out vitamins if there is a deficiency.
open question: unfortunately I have no further knowledge on urinary vitamin testing, no labs and no papers
(the GPL OAT contains a very few vitamins)
test vitamins in cells.
again for the same reason of vitamin imbalances reinforced by b6 intake.
I only know of Spectracells wbc vitamin test, which has a largely positive discussion on quora:
https://www.quora.com/How-legitimate-is-SpectraCell-micronutrient-blood-testing
and some papers partially backing it up. having said that, the method is not scientifically proven at all.
open question: any further vitamin tests in cells? any papers, for example if vitamin status in one cell type can extremely differ from vitamin status in another cell type?
toxins from the gut inhibiting uptake / utilisation of B6
test: urinary arabinose, available from many labs, among others, GPL
Dr Shaw from GPL mentioned somewhere that this by-product of Candida inhabiting the gut inhibits the uptake of B6. dont know any more if uptake in blood or cells. Didn't care to find any sources to validate this statement as my arabinose is sometimes normal, sometimes only moderately elevated at a level that so many people have who do surely not have my issues.
open questions: are there other gut-derived toxins inhibiting uptake or utilisation of vitamins? any chance this causes neuropathy (e.g. by causing vitamin imbalance or by causing buildup in neurons and deficit elsewhere)?
test for SIBO, low gastric motility and slow total gut transit time:
bad microbes in the gut that eat your vitamins before you get any. some produce neurotoxins. these neurotoxins slow down peristalsis, which helps them. peristalsis is the best defense of the gut against microbial overgrowth, because it moves them out.
!!!reference!!!
so producing neurotoxins is a very good strategy for them.
!!!insert here link!!!
open question: can such neurotoxins cause polyneuropathy?
what I know however for sure is that all my polyneuropathy issues started with taking B1 orally (the probably last time in my life I took a vitamin orally!!) and then, 2 days later, taking stuff that kills gut microbes caused neuropathy within hours. I tried it out repeatedly to make sure which vitamin caused it and if it is really killing microbes. it is killing microbes, I tried different things. and it is really b1. only since this initiation, I became sensitive to B6 (without any killing of microbes. and it comes immediately within 1-2 h after taking it), unfortunately also transdermally, but only if taken in bigger than minuscule doses. I had however quinolinic acid issues, minor polyneuropathy signs, diminished gastric motility and SIBO already years before.
strep needs B6 for growth. thanks to
@dannybex for the link
http://iai.asm.org/content/42/1/414.full.pdf
the following has nothing to do with polyneuropathy, it has to do with why one may need more than an RDV of B6:
inborn errors of B6 metabolism
the probably best list, grouped into categories of B6 problems:
http://www.ncbi.nlm.nih.gov/pubmed/16763894
a testing method for inborn errors of B6 metabolism:
https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0034-1390552
now, they are epilepsy researchers and so their patients suffer from epilepsy. however, neither the genes nor the b6 metabolism errors have anything to do with epilepsy directly. these are simply errors that lead to low serotonin via inhibition of b6 metabolism.