Evaluation of VACUTAINER PLUS Low Lead tubes for blood lead and erythrocyte protoporphyrin testing.

Lead poisoning is an important preventable environmental health problem. Blood lead concentrations as low as 100 μg/L (0.48 μmol/L) in whole blood have been shown to affect children’s neuropsychologic or cognitive performance adversely (1)(2)(3). In view of this, in 1991 the Centers for Disease Control and Prevention (CDC) lowered the concentration of lead in blood considered safe from 250 to 100 μg/L (from 1.21 to 0.48 μmol/L) (4). This lowered threshold has been reaffirmed by the CDC in their 1997 document on screening children for lead exposure (5). Before 1991, erythrocyte protoporphyrin (EP) was the standard test for screening children for lead poisoning; however, it was subsequently found to be an insensitive predictor of blood lead concentrations above the lower threshold (6). However, serial EP measurements, paired with matching blood lead measurements, are still useful in managing children with lead poisoning. In the absence of additional exposure of the child to lead, the EP concentration will continue to decrease at a faster rate than is reflected by the blood lead concentration as lead reequilibrates among blood, soft tissue, and bone stores. Another recommendation in the 1991 CDC statement was to screen all children 6 months to 6 years of age for lead poisoning, using a direct blood lead measurement. Venous blood is preferred for blood lead measurement because capillary measurements may be falsely increased by skin contamination with lead. The issue …

铅中毒是一个重要的可预防的环境卫生问题。全血中低至100微克/升（0.48微摩尔/升）的血铅浓度已被证明会对儿童的神经心理或认知表现产生不利影响（1）（2）（3）。鉴于此，1991年美国疾病控制与预防中心（CDC）将被认为安全的血铅浓度从250微克/升降低到100微克/升（从1.21微摩尔/升降低到0.48微摩尔/升）（4）。CDC在其1997年关于儿童铅暴露筛查的文件中再次确认了这一降低后的阈值（5）。1991年之前，红细胞原卟啉（EP）是筛查儿童铅中毒的标准检测方法；然而，随后发现它对于高于较低阈值的血铅浓度是一种不敏感的预测指标（6）。然而，连续的EP测量，结合相应的血铅测量，在管理铅中毒儿童方面仍然有用。在儿童没有额外铅暴露的情况下，随着铅在血液、软组织和骨骼储存库之间重新平衡，EP浓度将继续以比血铅浓度所反映的更快的速度下降。 1991年CDC声明中的另一项建议是使用直接血铅测量方法对所有6个月至6岁的儿童进行铅中毒筛查。测量血铅时首选静脉血，因为皮肤铅污染可能会使毛细血管测量值假性升高。这个问题……