Peck Heather R, Timko Denise M, Landmark James D, Stickle Douglas F
Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.
Clin Chim Acta. 2009 Feb;400(1-2):103-6. doi: 10.1016/j.cca.2008.10.020. Epub 2008 Oct 30.
Sample collection instructions for the bloodspot lead screening program conducted by the Nebraska Medical Center recommend continuous application of a single finger-stick blood drop per printed filter paper circle (a volume of approximately 50 microl). In this study, we assessed whether apparent blood volumes and geometries of finger-stick bloodspot samples submitted for lead testing were consistent with collection recommendations.
Samples were 422 extra bloodspots from 138 patients that were submitted for lead analysis. Using image analysis, apparent blood volumes were computed by comparison of bloodspot areas to bloodspot areas for standards of known volume. Circularity of samples was also assessed by image analysis.
Mean blood volume (25+/-13 microl) was approximately 50% of that needed to fill a printed circle. The distribution of volumes had three local maxima, consistent with bloodspot formation by multiple discrete applications of blood drops of small volumes (17+/-6 microl) rather than by continuous application of blood. Multi-drop samples were also apparent from non-circular geometries.
Bloodspots submitted for lead analysis showed an apparently inherent drop volume of less than 20 microl per drop and the application of multiple drops. Non-ideality of such specimens indicates the need for continuing education of bloodspot collectors.
内布拉斯加医学中心开展的血斑铅筛查项目的样本采集说明建议，在每张印刷好的滤纸圆圈上持续滴加一滴手指血（体积约为50微升）。在本研究中，我们评估了提交进行铅检测的手指血斑样本的表观血量和几何形状是否符合采集建议。
样本为来自138名患者的422份额外血斑，用于铅分析。通过图像分析，将血斑面积与已知体积标准的血斑面积进行比较，计算表观血量。还通过图像分析评估样本的圆形度。
平均血量（25±13微升）约为填满一个印刷圆圈所需血量的50%。血量分布有三个局部最大值，这与通过多次离散滴加小体积血滴（17±6微升）而非连续滴血形成血斑一致。从非圆形几何形状中也可明显看出多滴血样本。
提交进行铅分析的血斑显示，每滴血的表观固有滴体积小于20微升，且存在多次滴血情况。此类样本的不理想状况表明有必要对血斑采集者持续开展培训。
