血浆叶酸两种常用检测方法检测结果的比较

目的:比较目前常用的两种叶酸检测方法(微生物改良法和核素放射免疫法)的检测结果,寻找两者间的相互关系或规律.方法:对88例血浆标本分别进行微生物改良法和核素放射免疫法检测,通过曲线拟合,得到回归方程;利用回归方程对采自我国南北方部分地区2 422例成年人血浆标本的微生物改良法检测结果进行换算,比较两种方法得到的血浆叶酸营养状况在地区、季节和性别的分布特征,及其与饮酒、吸烟、体质指数以及高同型半胱氨酸血症危险性关系.结果:核素放射免疫法与微生物改良法的检测结果之间呈线性相关,相关系数r=0.879(P=0.000),回归方程为y=0.683X 0.308(其中X,y分别为微生物法和放免法检测值的自然对数值);两种方法得到的血浆叶酸营养状况在地区、季节和性别的分布特征,及其与饮酒、吸烟、体质指数以及高同型半胱氨酸血症危险性关系相同;微生物法检测血浆叶酸水平明显高于放射免疫法.换算后的放射免疫法数据显示,我国19.9%南方人群和67.1%北方人群血浆叶酸低于6.8 nmol/L.结论:微生物改良法与核素放射免疫法检测结果之间有较好的相关性;但对评价人群叶酸营养水平而言,两种方法检测结果之间差异较大.建议将微生物改良法血浆叶酸缺乏判定标准定为10.5 nmol/L,但有待进一步研究证实.

Comparative study of the detection of plasma folate with microbial assay and radioimmunoassay

Objective: To compare two methods (microbial assay and radioimmunoassay) for measuring plasma folate concentrations, and to examine the relationship between plasma folate levels, and alcohol consumption, tobacco use and body mass index, and the risk of hyperhomocysteinemia in China. Methods: We used a microtiter plate microbial assay and a radioimmunoassay to measure the folate concentration in 88 plasma samples. After comparing the results of these two methods and fitting a regression line, we examined the geographical, seasonal, and gender differences in folate concentration of plasma collected from 2 422 adults in south and north areas in China, and evaluated the association of plasma folate concentration, with alcohol consumption, cigarette smoking, and body mass index, and with the risk of hyperhomocysteinemia, using the data from the two assays. Results: The data from the two assays had a linear relationship ( r =0.879, P =0.000); the regression was Y =0.683 X 0.308 (where X and Y were nature logarithmic transformations of plasma folate by microbial assay and radioimmunoassay, respectively); however, the mean plasma folate levels by microbial assay were much higher than those obtained by radioimmunoassay. Both data sets showed similar plasma folate distributions among Chinese adults, associations with other risk factors, and the risk of hyperhomocysteinemia. We estimated that 19.9% of the Southerners and 67.1% of the Northerners had plasma folate concentrations by radioimmunoassay lower than the 6.8 nmol/L used to define plasma folate deficiency. Conclusion: There is a linear relationship between plasma folate levels determined by microbial assay and radioimmunoassay, but because of the different levels obtained in the two assays, it is difficult to use the microbial assay results to evaluate folate status at this time. The use of 10.5 nmol/L as a cut off for plasma folate deficiency by microbial assay needs further study.