Relationship between the Levels of Holotranscobalamin and Vitamin B12.
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 between-run 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 micromol/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.
Woo
Kwang Sook
KS
Department of Laboratory Medicine, Dong-A University College of Medicine, Busan, Korea.
Kim
Kyung Eun
KE
Park
Joon Seok
JS
Park
Joo In
JI
Han
Jin Yeong
JY
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D014155:Transcobalamins / Q000032:analysis*; D014805:Vitamin B 12 / Q000097:blood*; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis; D055815:Young Adult
D015415:Biomarkers; D014155:Transcobalamins; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12