Private testing for B12 and MMA (UK)

[Shoe2]

Looking for some pointers from others.

I have felt unwell since Jan 23. URQ pain, malaise, tingling on chest and in thumbs and fingers, cold extremeties, chest pain, shortness of breath , distinct and new varicose veins in ankles. Also poor fat absorption. I had thought maybe liver. But ultrasound and CT and bloods say liver is fine and told just bloating dominant IBS.

Only bloods out of range was low B12 at 196 (Jan 23) on 197-771 . I pushed GP to do the MMA which was 665 (normal being below 280) (April 23) GP agreed then give B12 loading dose and then every 3 months I had loading in May and been getting the 3 monthly since. So was pointed to functional B12 deficiency and maybe PA (with BAM ?) by some helpful peeps on the liver space of here)

My WBC was also at the low end but just in range but More recent bloods show WBC below at 3.7 (4.0 bottom of range).

I tested negative for IFA though

I am now due a 3 month booster but wondered if it is worth paying for a B12 serum and MMA test privately (GP won’t do them again) to see if levels are better before I dose again. And are any other blood tests useful in identifying (or ruling out) PA or B12 Functional deficiency.

Any thoughts on testing would be helpful.

Thanks

[FlipperTD]

Hi Shoe2. I am a retired scientist, not a medic.

General advice is not to repeat B12 assays once replacement therapy has started. Your GP is correct in refusing to repeat the test. It's usually the other way round, with medics wanting to repeat the test once treatment has started, and then getting confused when a high level is found, so I give the GP a gold star on this one.

Neither would I [personally] consider getting a private B12 test done either. The methods don't necessarily compare, so interpreting the result is fraught with difficulty. Trust your GP. If you don't trust your GP, then you could seek another, but it seems like you've got a good one.

If you had macrocytosis before treatment commenced, then it would be reasonable to expect that the MCV would have fallen on commencement of treatment, and that's an easy one for you.

I hope this helps.

[WIZARD6787 in reply to FlipperTD]

Hey FlipperTD,

In the USA the private labs are regulated by the same agency as are blood prick tests. So they are equivalent.

Here many physicians use the private labs and insurance cover the cost.

[FlipperTD in reply to WIZARD6787]

Hi Wiz. Thanks for the response.

Labs in the UK have accreditation processes which ensure quality. However, that still need not mean that results are entirely comparable, because each lab organisation selects its own choice of analysers, for their own purposes, and there may be bias between different manufacturers. This isn't very likely with the FBC, although MCV measurement can vary due to the technology involved. Likewise, sample types can affect the reliability of results. A 'good venepuncture' from an experienced phlebotomist generally provides the best starting point, whereas a finger prick sample doesn't. If the finger prick sample is obtained by the patient then that's another variable. Then, if the sample suffers any delay in processing, that's another variable to control. For best results I'd always recommend using the same lab for repeat analyses if possible.

[WIZARD6787 in reply to FlipperTD]

I see no compelling reason not to take advantage of the current science of the finger prick sampling method performed by a capable paricient. The cost is less and at least in the United States the agency that approves labs and procedures can be trusted to compare the two methods. It is a very simple task to compare the two.

One could have a test done both ways and compare the two but that has already been done by the agency that certifies tests and procedures.

Then again I don't use a slide rule anymore🙂

[FlipperTD in reply to WIZARD6787]

You have a point, but the collection of fingerprick samples is prone to contamination that we see less in good venous samples. Some methods work well with either, but some don't work anything like as well on fingerprick samples. There was the case of Theranos but it's probably better to steer clear of that one!

Tests on whole blood require the sample to be mixed. Mixing microsamples is less effective than whole blood venous samples, although the majority of tests are done on serum, from clotted samples. Capillary samples can be adequate, although haemolysis is probably more likely from those and may affect the results.

I only have three slide rules on the shelf behind me, and two are substantially wood!

[WIZARD6787 in reply to FlipperTD]

No need to stay clear of Theranos. It is an example of that science with regards to something as easily compared as blood testing is not susceptible to fraud that harms the person being tested or affects the results.

The home testing has the advantage of not being contaminated in a collection point where multiple visius and bacterial sources exist due to the number of sources. (sick people)

'Better' includes cost. I drive a Mazda not a Lexus.

[FlipperTD in reply to WIZARD6787]

A friend in the US alterted me to the existence Theranos, and his firm were one of the ones taken in, or gambling 'just in case it would work'. I told him it was an 'Emperor's New Clothes' outfit from what they were offering, and Ms Holmes worked her magic on others too.

Some analytes don't like being delayed in transport or suffering temperature abuse, so the added risk of going to one of these places sometimes has to be faced.

I drive a Toyota! [I did drive a Mazda but it spent more time in the dealer than on my drive, but I still like the brand.]

[WIZARD6787 in reply to FlipperTD]

A good technician should be able to tell if the blood sample is not testable due to temperature issues etc.

[FlipperTD in reply to WIZARD6787]

Sorry, but you're wrong there. If the analyst isn't provided with all of the information, then it's very difficult. If there hasn't been temperature logging from the collection to delivery [as there would be for example in blood for transfusion] then it's a lottery. Getting the information into the system is another challenge on top of everything else. I don't think this is getting us anywhere useful.

[WIZARD6787 in reply to FlipperTD]

If a sample is contaminated or not testable due to temperature fluctuations that the protocol currently used will identify it and another sample will be requested. Same with bacteria.

It was useful to me as now I know there is no reason to not use a finger prick in 2023 in the USA. I was going to do the work anyway this was a good motivator.

The allowable standard in the USA for finger prick testing is about 10% that is well within the criteria for what I would use the test results for. I did not bother to check the standards for venous samples.

The finger tip method is used routinely in clinical settings currently in the USA to monitor which is how I would be using the results.

I did find it interesting they use a finger tip test in the ER here to check for blood loss instantly.

[FlipperTD in reply to WIZARD6787]

Contaminated or faulty samples are a particular issue in laboratory work. For example, visible haemolysis can be spotted when loading centrifuged serum samples, and eliminated prior to analysis. However, a much lower degree of haemolysis isn't visible, but almost completely invalidates the sample, and at that point a repeat would be requested. It is inevitable that some results affected by storage or handling artefacts will escape and be issued. They may be in the 'feasible' range rather than 'impossible' range, but still could mislead.

Needless to say, this virtually doubles the cost and adds delays. Analysis of where the faulty samples come from can give clues to problems with sites or staff, but this is an extra load over and above the analytical work.

Life is difficult enough with what we assume are good quality venous samples, but capillary samples add another level of complexity. Lab handling of capillary samples adds extra workload too, usually requiring manual handling, but that's a minor complication. Good luck getting a valid platelet count from a finger prick sample!

[WIZARD6787 in reply to FlipperTD]

All true but not germain to the decision of accepting the science of finger pricks. Which I do.

[helvella in reply to FlipperTD]

I suspect there are many who would welcome an alternative to fingerprick testing.

In the UK, if your NHS access refuses a test, you have the choice of a private lab. (Ironically, some NHS labs offer "private" testing.) But the cost of venous phlebotomy is often too great - potentially being greater than the actual analyses, especially if living in an out of the way part of the country.

Also, some struggle to get adequate blood from doing their own finger-pricks.

Is there any approach which is better than fingerprick but not as costly as private phlebotomy?

[FlipperTD in reply to helvella]

Wandering off the topic, I was charged £35 for a watch battery replacement. £5 would have been reasonable.

Considering the staff costs and overheads for phlebotomy, I'd love to see the breakdown of a charge for private phlebotomy!

The problems stem from the gatekeeper; you need a GP to authorise the procedure under the NHS. They are cost-conscious, and some moreso than others. They're spending public money after all. If however anything is done privately, then the costs can be quite scary. Technically, phlebotomy provides better quality samples for testing. Fingerprick samples can be adequate for some tests, but certainly not for everything.

[Shoe2 in reply to FlipperTD]

Thanks that is helpful.

[Hockey_player]

Did you keep getting B12 every other day until the symptoms went away (tingling). I have pernicious anemia. I find that every 3 weeks is not quite often enough. I am not sure where they get the every 3 month dosing for B12. I suspect it is perfectly fine for people with a dietary insufficiency but question that it is often enough for pernicious anemia.

[WIZARD6787 in reply to Hockey_player]

The guidelines suggest that if symptoms return after any deviation from EOD that the injections be moved closer together.

[Shoe2 in reply to Hockey_player]

I had loading doses 3 times a week for 2 weeks. Then every 3 months. Loading doses stopped tingling and then the thumb and finger nerve pains stopped (symptoms wee akin to Raynauds). I guess go with the 3 monthly and track symptoms and see if more frequent doses worth trying.

[Madman070578 in reply to Shoe2]

Hi Shoe, I’m in the UK too, and my GP only prescribed me 4 loading doses. I went back and saw another, saying that whilst I still has severe pins and needles the guidelines state to carry on every other day. He bluntly refused (I’m not sure is the treatment varies between England and Wales) or if it is down to each health board or even practice.

I’ve been tested for the IF antibodies and it has been nearly 3 working weeks and the result hasn’t come back.

He is saying the best I’m going to get is jabs every 3 months.