ACTIVE-B12
6Pages

the next level of B12 testing

Vitamin B12 – an essential nutrient Vitamin B12 is an essential nutrient (can only be obtained from the diet) and is a vital component in many cellular functions including DNA synthesis. Deficiency can result in cognitive problems, dizziness and numbness and if left untreated, irreversible neurological damage. Vitamin B12 deficiency is a major public health issue and is widespread. Estimates suggest that up to 20% of the elderly population may be deficient or deplete in Vitamin B121 and with an increasingly ageing global population the situation will only worsen. Among other population...

What is Active-B12? Three carrier proteins are involved in the transport of Vitamin B12 around the body - Intrinsic Factor (IF), transcobalamin (TC) and haptocorrin (HC). When transcobalamin and haptocorrin bind Vitamin B12 the resulting complexes are known as holotranscobalamin (HoloTC) and holohaptocorrin (HoloHC). HoloTC represents only 10-30% of the Vitamin B12 circulating in the blood but is the ONLY form of Vitamin B12 that is taken up and used by cells of the body, hence it's other name... ACTIVE-B12. Only transcobalamin transports Vitamin B12 from its site of absorption in the ileum...

Measuring B 1 2 The current front-line test for assessing Vitamin B12 status is the total B1 2 assay but this test has a number of important limitations: False positives A proportion of individuals with Total B1 2 levels below the common cut-off of 148pmol/L (200pg/mL) show no clinical or biochemical evidence of deficiency2. False negatives Conversely, neuropsychiatric and metabolic abnormalities can occur with total B1 2 concentrations well within the normal reference interval2,3. Measures all circulating Vitamin BI2 But not all B12 in the blood is available to be used by the body. Only B1...

Performance of Active-B12 Active-B12 offers a more accurate assessment of Vitamin B12 status than Total B12 or MMA9. Using Active-B12 Active-B12 may be used as a direct replacement for the total B12 test or as a secondary test to resolve total B12 indeterminate results10: Subjects at risk of B12 deficiency Active-B12 <35pmol/L Likely deficient Unlikely deficient* * Renal patients should be further investigated Likely deficient Unlikely deficient* * Due to false positives and false negatives, all total B12 results could be confirmed with Active-B1

A novel monoclonal antibody has been developed which is highly specific for holoTC, allowing simple, direct immunoassays for quantifying Active-B 1 2. Such assays remove the need for the cumbersome pre-ana.lyt.ical denaturation steps needed for most Vitamin B1 2 assays thereby removing a source of variability. References I. Pfeiffer C et al Am J Clin Nutr 2007;86:718-27 2. Green R et al. Baillieres Clin Haematol.,I995;8:533-6 4. Snow CF Arch Intern Med., 1999 ; 159 :1289-98. 6. Hvas AM et al., Ugeskr Laeger, 2003; 165: 1971 -6. 7. Herrmann W et al Curr Drug Metab. 2005; 6 : 47-53 8....