HoloTC - B12 sérica - Hcy

Como a avaliação de B12 é de suma importancia no acompanhamento de um paciente vegetariano (assim como em idiosos e pacientes bariatricos). Achei esse artigo hoje sobre avaliação de B12, utilizando o HoloTC como adicional ao exame de B12 sérica, ainda não sei se é uma realidade (R$ acessivel) em nossos laboratorios.

Relationship between the Levels of Holotranscobalamin and Vitamin B12

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To date, the determination of serum vitamin B12 levels has been the most common laboratory
test for the assessment of vitamin B12 status; however, the diagnostic accuracy of this test is low.
To obtain a more sensitive marker, a new test to measure holotranscobalamin (holoTC) levels has
been introduced. In this study, we assessed 45 patients for whom a vitamin B12 test had been requested
and 139 anemic patients. We investigated the associations between the levels of homocysteine
(Hcy) and those of holoTC, serum vitamin B12, and folate and assessed the diagnostic
value of holoTC levels as a marker for vitamin B12 deficiency. We also determined the precision of
the AxSYM holoTC assay by calculating the coefficient of variance (CV). The within-run and betweenrun
precision values were excellent, as all CV values were less than 3.5%. The holoTC levels were
low (<35 pmol/L) in 7 samples, and 6 of these samples had normal total serum vitamin B12 levels.
In 2 of these samples, high Hcy levels (>12 mmol/L) indicated vitamin B12 deficiency. Thus, the
holoTC levels were more sensitive than the serum vitamin B12 levels for indicating vitamin B12 status.
If the serum vitamin B12 level is 151-300 pmol/L, the levels of holoTC alone or in combination
with serum vitamin B12 levels are likely to be more useful markers than serum vitamin B12 levels
alone. (Korean J Lab Med 2010;30:185-9)