blood tests

[ninja1]

doc won’t accept this active test as my serum test is 354. 191-663 b12

Folate 4.3. 3.89 - 26.8

Quite a difference I’m at a loss

[Cherylclaire Forum Support]

The active test measures only the useful B12 in your blood. Yours is below what would be called "normal". The total serum B12 measures both the useful and useless, and yours appears fine - but isn't if the active test is accurate.

If your doctor is sceptical about this test result, s/he could, since both folate and vitamin D aren't looking too great either, get your active B12 test redone on the NHS.

An in-range serum B12 test result would not give any true indication of what percentage can be utilised. Less than 10% being active is unusual - all the more reason to investigate further in my eyes.

[ninja1 in reply to Cherylclaire]

They won’t do it because serum in range I feel rotten I’m always asleep tachycardia shortness of breath on exertion. I think I need to find a private clinic that would retest and treat I’ve been watching my other levels dropping for months mch very low Mchc very low etc as I have posted earlier now my Mcv is starting to drop was 85 now 82 but all my notes say is abnormal but just out of range I’m at a loss what to do

[Sleepybunny]

Hi,

I'm wondering if your GP understands what is meant by Active B12.

Active B12 is also called holotranscobalamin or holoTC.

As  Cherylclaire says an Active B12 test only measures the B12 that the body can use.

As you're in UK, maybe you could point out to GP that the new NICE B12 deficiency guideline published this year (2024) suggests doctors consider testing Active B12.

NICE B12 deficiency guideline

pernicious-anaemia-society....

Some NHS GPs are reluctant to accept private results but a significant result in a private test should be enough to nudge them to order same test on NHS or to refer you to a specialist who can order this test.

Have you considered putting your concerns into a short letter to GP and maybe copied to practice manager as well. Always keep a copy.

I think it's harder for doctors to ignore what's in a letter. Letters to GP are supposed to be filed with medical notes. I used to include a request that a copy was filed with my medical notes to make sure it was.

b12info.com/writing-to-your...

I left detailed replies with useful info in this thread.

Help Needed! Have I got Pernicious Anaemia?

healthunlocked.com/pasoc/po...

I'm not medically trained.

[ninja1 in reply to Sleepybunny]

She says all is well as she did intrinsic f test normal no action

[ninja1 in reply to ninja1]

ntrinsic f test

[Gambit62 Administrator in reply to ninja1]

It sounds like your GP needs to be made aware that the IF test is good for confirming PA as the cause of a B12 deficiency but doesn't rule it out as it gives false positives 40-60% of the time.

Below is an extract from the guidelines produced by the British Society for Haematology

b-s-h.org.uk/guidelines/gui...

which references this document

onlinelibrary.wiley.com/doi...

Which contains this statement on anti-IFAB test (emphasis added)

Anti-intrinsic factor antibody (anti-IFAB)

The finding of a low total serum cobalamin level may be further evaluated by testing for anti-IFAB. If positive, the test has a high positive predictive value (95%) for the presence of pernicious anaemia (Toh et al, 1997), with a concurrent low false positive rate (1–2%) i.e. a high specificity. It identifies those patients with a need for lifelong cobalamin replacement therapy. IFAB is positive in 40–60% of cases (Ungar et al, 1967), i.e., low sensitivity, and the finding of a negative IFAB assay does not therefore rule out pernicious anaemia (hereafter referred to as AbNegPA). In addition, the positivity rate increases with age (Davidson et al, 1989) and in certain racial groups [Latino-Americans and African-Americans; (Carmel, 1992)].

[Sleepybunny in reply to ninja1]

"She says all is well as she did intrinsic f test normal no action"

I'm not medically trained but I think your GP is wrong to assume that a normal range result in IFA test rules out PA.

Have you asked your GP if it's possible you have Antibody Negative PA?

About half of people with PA get a negative result in IFA test. Your GP can see an explanation of this in the Background Information section of this document

"NICE CKS Anaemia - B12 and Folate deficiency"

You could look this document up yourself.

You could also show GP the PAS page for health professionals.

GP could look in section "Key Points in the Diagnosis of Pernicious Anaemia" where it says that antibodies to IF are only present in around 50% of patients.

pernicious-anaemia-society....

Flowchart below from UK document below mentions Antibody Negative PA

Might be worth showing this to GP.

stichtingb12tekort.nl/engli...

Are you a PAS member?

PAS membership is separate to membership of this forum.

pernicious-anaemia-society....

If you are, might be worth ringing their members' helpline.

pernicious-anaemia-society....

Other useful info in the thread I mentioned at bottom of my other reply.

[ninja1 in reply to Sleepybunny]

I’ve ordered active test again with someone else to compare