Active-B12
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Active-B12(Holotranscobalamin) is the biologically active VitaminB12 that can be taken up by cells for subsequent metabolic use. It accounts for only 20-30% of the total Vitamin B12 in the bloodstream and is the only form of Vitamin B12 that can be directly absorbed and utilised by the body's cells. holohaptocorrin Clinical significance: Pregnancy Total Vitamin B12 levels may be affected by pregnancy by nearly 50%, while active-B12 is almost unaffected by pregnancy. Vitamin B12 deficiency increases risk of pregnancy complications Excess folate and vitamin B12 during pregnancy increase risk of autism in newborns Women during pregnancy are more likely to be affected by vitamin B12 deficiency due to increased metabolic demands caused by physiological activities (e.g. growth of the placenta, foetus and maternal tissues) At the 2016 Autism Research Conference, academics at Johns Hopkins University reported a study showing plasma folate > 59 nmol/L and vitamin B12 > 600pmol/L during gestation. 17.6-fold increase in neonatal autism risk Neonatal autism risk Spontaneous miscarriage Habitual miscarriage Fetal neural tube defects Fetal intrauterine growth restriction Low birth weight babies High folic >59nmol/L High VB12-500 pmol/L High folate & high VB12 2 times Excess 3 times Geriatric population Pernicious anaemia produces high titres of antibodies to internal factors, which may interfere with serum total VB12 measurements and lead to false-negative results. Active-B12, as a direct indicator of cellularly available AB12, can provide more accurate diagnostic information. For the elderly, Active-B12 testing can help with early warning and intervention to avoid permanent neurological damage. Cognitive disorders such as Alzheimer's disease are associated with AB12. False normal B12 Results and Risk of Neurological Damage parasthesiae, loss of joint position serum methyimalonic acid and to publicise their concerns on sense, or megaloblastic anaemia and measurement of intrinsic factor problems with current B12 assays a "normal" B12 result, clinicians are antibody, Treatment with B12 advised to request storage of serum for should not be delayed to avoid interference resulting in normal further testing and are advised to treat values despite severe cobalamin the patient with B12 replacement damage. For further information deficieney. The Committee advises therapy. Further testing may include please see this recent paper. that where there is a discordance repeat testing by an alternative Bl2 Carmel R, Argawal YP. Failures between the clinical features of assay.holotranscobalamin assay, of cobalamin assays in pernicious E-mail: overseas@poclight.com Website: www.poclightbio.com Animal Fluency Test Scores UK NEQAs Haematinics is keen Digit Symbol Substitution Test Modified CERAD-WL The Association for Clinical Biochemistry l Issue 600 | April 2013 Modified CERAD-DR generation of Homogeneous CLIA

Advantages of Active-B12: High sensitivity: No interference from internal factor antibodies: Directly reflects cell-available VB12 Early diagnosis and intervention Assessment of cognitive function Vitamin B12 grey zone account for 67% of patients Active-B12 helps to further differentiate Serum active-Bl2 was the best predictor, with a ROC of 0.9, 67% of patients were in the 'grey zone’ of total VB12. which was significantly better than serum total vitamin B12 and IMA. 180 patients (38%) had total AB12 >150 pmol/L This study supports holo'Tc as a first-line test for assessing vitamin B12...