Bondu Joseph Dian, Nellickal Arun Jose, Jeyaseelan L, Geethanjali F S
Department of Clinical Biochemistry, Christian Medical College, Vellore, Tamil Nadu 632004 India.
Department of Biostatistics, Christian Medical College, Vellore, Tamil Nadu India.
Indian J Clin Biochem. 2020 Jul;35(3):367-372. doi: 10.1007/s12291-019-00835-y. Epub 2019 Jun 12.
About 15-40% India is Vitamin B12 deficient (commonly diagnosed by total Vitamin B12) but, as only holoTC (active form) is taken up by body cells, thus measuring holoTC is more reflective of Vitamin B12 status than the former. We aimed to assess diagnostic accuracy of serum holoTC in comparison with total Vitamin B12 and total Homocysteine (HCY) as indicator of serum Vitamin B12 status. 217 human subjects (99 males and 118 females) ranging from 17 to 83 years were divided into Vitamin B12 deficient (n = 70), borderline (n = 100) and sufficient groups (n = 47) who were further assessed for markers of Vitamin B12 deficiency-holoTC, HCY, Mean Corpuscular Volume (MCV), Folate, heamoglobin and creatinine. Samples were analysed using Siemens Advia Centaur Xpi. Total Vitamin B12 deficient group had - 84.3% holoTC deficient; 15.7% holoTC sufficient; 72.9% with elevated HCY; 27.1% with normal HCY; 11.4% with megaloblastic anaemia. Borderline group had - 34% holoTC deficient; 28% elevated HCY. A strong positive correlation was found between Total Vitamin B12 and holoTC (r = 0.754, = <0.001) but strong negative correlation existed between holoTC and HCY (r = - 0.471, = <0.001). Concordance between Total Vit B12 and HCY (Kappa index = 0.51, < 0.001); between holoTC and HCY (Kappa index = 0.52, = <0.001) were statically significant but the latter had a better sensitivity and specificity. Also, statically significant association exists between Total Vitamin B12 and holoTC with HCY ( = <0.001). Therefore, it is ascertained that Active Vitamin B12 assay is a better test and can be considered as an early marker of vitamin B12 deficiency.
印度约15%-40%的人存在维生素B12缺乏（通常通过总维生素B12进行诊断），但由于只有全转钴胺素（活性形式）被人体细胞摄取，因此测量全转钴胺素比测量总维生素B12更能反映维生素B12的状态。我们旨在评估血清全转钴胺素与总维生素B12和总同型半胱氨酸（HCY）相比作为血清维生素B12状态指标的诊断准确性。217名年龄在17至83岁之间的受试者（99名男性和118名女性）被分为维生素B12缺乏组（n = 70）、临界组（n = 100）和充足组（n = 47），并进一步评估维生素B12缺乏的标志物——全转钴胺素、同型半胱氨酸、平均红细胞体积（MCV）、叶酸、血红蛋白和肌酐。样本使用西门子Advia Centaur Xpi进行分析。总维生素B12缺乏组中，84.3%的人全转钴胺素缺乏；15.7%的人全转钴胺素充足；72.9%的人同型半胱氨酸升高；27.1%的人同型半胱氨酸正常；11.4%的人患有巨幼细胞贫血。临界组中，34%的人全转钴胺素缺乏；28%的人同型半胱氨酸升高。总维生素B12与全转钴胺素之间存在强正相关（r = 0.754，P = <0.001），但全转钴胺素与同型半胱氨酸之间存在强负相关（r = -0.471，P = <0.001）。总维生素B12与同型半胱氨酸之间的一致性（kappa指数 = 0.51，P < 0.001）；全转钴胺素与同型半胱氨酸之间的一致性（kappa指数 = 0.52，P = <0.001）具有统计学意义，但后者具有更好的敏感性和特异性。此外，总维生素B12和全转钴胺素与同型半胱氨酸之间存在统计学意义的关联（P = <0.001）。因此，可以确定活性维生素B12检测是一种更好的检测方法，可被视为维生素B12缺乏的早期标志物。
