Laser-Forschungslabor, LIFE Center, LMU - Ludwig-Maximilians-Universität Munich, University of Munich Medical Center, Munich, Germany.
Dr. von Hauner Children's Hospital, LMU - Ludwig-Maximilians-Universität Munich, University of Munich Medical Center, Munich, Germany.
Pediatr Res. 2019 Feb;85(3):349-354. doi: 10.1038/s41390-018-0247-x. Epub 2018 Dec 9.
Reliable screening for iron deficiency (ID) has required a blood sample and cost-intensive laboratory measurements. A novel method to non-invasively measure erythrocyte zinc protoporphyrin (ZnPP), an established marker for ID, is evaluated in children.
ZnPP was determined non-invasively by fluorescence measurements on the wet vermillion of the lower lip in 99 hospitalized children aged 9 months to 5 years. For comparison, conventional ID parameters and ZnPP were determined from blood samples.
The non-invasively measured ZnPP values had limits of agreement (LoA) of 14 µmol ZnPP/mol heme (95% confidence interval: 9-20) compared to fluorescence measurements directly in blood. Repeated high-performance liquid chromatography reference determinations had comparable LoA of 14 µmol ZnPP/mol heme (9-17). Non-invasive ZnPP measurements had sensitivity and specificity of 67% (39-88%) and 97% (91-99%), and negative and positive predictive value of 94% (90-97%) and 80% (55-93%), for detecting ID as defined by the soluble transferrin receptor (sTfR). In groups with more severe ID as defined by serum ferritin and sTfR, higher ZnPP values were found, with the highest ZnPP values for the group with ID anemia.
Non-invasive ZnPP measurements are reliably feasible in children. The simple and fast method has the potential to enable wide-spread screening for ID.
可靠的缺铁（ID）筛查需要采集血样并进行昂贵的实验室检测。本研究评估了一种新的非侵入性方法来测量红细胞锌原卟啉（ZnPP），这是 ID 的一种既定标志物。
通过测量下嘴唇湿唇红部位的荧光强度，对 99 名 9 个月至 5 岁住院儿童进行非侵入性 ZnPP 检测。为了进行比较，还从血液样本中检测了常规 ID 参数和 ZnPP。
与直接在血液中进行荧光测量相比，非侵入性测量的 ZnPP 值的一致性界限（LoA）为 14µmol ZnPP/摩尔血红素（95%置信区间：9-20）。重复高效液相色谱参考测定的 LoA 也相当，为 14µmol ZnPP/摩尔血红素（9-17）。非侵入性 ZnPP 检测的敏感性和特异性分别为 67%（39-88%）和 97%（91-99%），阴性和阳性预测值分别为 94%（90-97%）和 80%（55-93%），用于检测可溶性转铁蛋白受体（sTfR）定义的 ID。在根据血清铁蛋白和 sTfR 定义的 ID 严重程度更高的组中，ZnPP 值更高，ID 贫血组的 ZnPP 值最高。
非侵入性 ZnPP 检测在儿童中是可靠可行的。这种简单快速的方法有可能实现 ID 的广泛筛查。
