El-Hajjar Dana F, Swanson Katherine H, Landmark James D, Stickle Douglas F
Nebraska Public Health Laboratory, Omaha, NE 68198-3135, USA.
Clin Chim Acta. 2007 Feb;377(1-2):179-84. doi: 10.1016/j.cca.2006.09.020. Epub 2006 Oct 31.
Lack of a second sample often precludes the ability to perform repeat lead measurements on filter paper bloodspot samples. We investigated whether annular specimens remaining from once-punched filter paper bloodspot specimens could provide accurate Pb measurements when measurements were scaled for the remainder area relative to the original punch area.
50 microl bloodspot specimens were prepared using Pb-spiked EDTA whole blood. After removal of 6 mm punches, bitmap images of the remainder specimens were obtained using a scanner. Image analysis was used to determine the bloodspot area of the remainder sample relative to the area of the original punch. Measurement of Pb for punches and for remainder specimens was performed by ICP-MS.
Area-corrected Pb measurements for remainder samples were significantly higher than for the punches, by an average factor of 1.52+/-0.12 (p<0.05, n=28). The difference was due to a discontinuity (an increase) in the per-area Pb at the bloodspot perimeter. Area-corrected results for annular specimens that excluded the perimeter were identical to those of the punch.
Area-corrected Pb measurement using annular once-punched bloodspot remainder specimens can accurately reproduce lead measurements obtained from the original punch when the bloodspot perimeter area is excluded.
由于缺乏第二个样本，通常无法对滤纸血斑样本进行重复铅含量测量。我们研究了从一次性打孔的滤纸血斑样本中剩余的环形样本，在将测量值按相对于原始打孔面积的剩余面积进行缩放时，是否能提供准确的铅含量测量结果。
使用添加铅的乙二胺四乙酸（EDTA）全血制备50微升血斑样本。去除6毫米的打孔样本后，使用扫描仪获取剩余样本的位图图像。通过图像分析确定剩余样本的血斑面积相对于原始打孔面积。打孔样本和剩余样本的铅含量测量通过电感耦合等离子体质谱法（ICP-MS）进行。
剩余样本经面积校正后的铅含量测量值显著高于打孔样本，平均系数为1.52±0.12（p<0.05，n = 28）。差异是由于血斑周边每单位面积的铅含量存在不连续性（增加）。排除周边区域的环形样本经面积校正后的结果与打孔样本相同。
当排除血斑周边区域时，使用环形一次性打孔血斑剩余样本进行面积校正后的铅含量测量能够准确再现从原始打孔样本获得的铅含量测量结果。
