Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark.
Clin Chem Lab Med. 2011 Nov;49(11):1883-5. doi: 10.1515/CCLM.2011.754. Epub 2011 Oct 14.
Active vitamin B12 absorption is followed by an increase in holotranscobalamin (holoTC) upon loading with a high physiological dose of the vitamin (the CobaSorb test). This study evaluates the use of a newly launched EIA kit for measurement of holoTC (active B12) in relation to the CobaSorb test.
Intra-assay imprecision and linearity of the EIA kit was examined, employing serum pools of increasing holoTC concentrations. For the CobaSorb test, holoTC was measured before and after loading with 3-times 9 μg of vitamin B12 employing both the in-house ELISA and the EIA kit (n=25).
The EIA kit showed an intra-assay CV between 2.2% and 5.8% for holoTC values ranging from 21 to 80 pmol/L. Employing diluted serum samples resulted in spurious high values of holoTC. The EIA kit performed well in relation to the CobaSorb test and classified the patients studied as capable of absorbing vitamin B12 (n=10) or not (n=15), as did the in-house ELISA.
The Active B12 (holoTC) EIA kit proved suitable for use with the CobaSorb test, but not for analysis of diluted serum samples.
在高生理剂量的维生素（CobaSorb 测试）负荷下，活性维生素 B12 的吸收会导致全钴胺素（holoTC）增加。本研究评估了一种新推出的 EIA 试剂盒在与 CobaSorb 测试相关的 holoTC（活性 B12）测量中的使用。
通过测量递增 holoTC 浓度的血清池，检查 EIA 试剂盒的批内不精密度和线性。对于 CobaSorb 测试，在使用内部 ELISA 和 EIA 试剂盒（n=25）对 3 倍 9μg 维生素 B12 进行负荷后，测量 holoTC。
EIA 试剂盒对 21 至 80 pmol/L 范围内的 holoTC 值的批内 CV 为 2.2%至 5.8%。使用稀释的血清样本会导致 holoTC 的虚假高值。EIA 试剂盒与 CobaSorb 测试相关，能够将研究患者分类为能够吸收维生素 B12（n=10）或不能吸收（n=15），内部 ELISA 也是如此。
活性 B12（holoTC）EIA 试剂盒适合与 CobaSorb 测试一起使用，但不适合分析稀释的血清样本。
