Disorders in iron metabolism are endemic globally, affecting more than several hundred million individuals and often resulting in increased rates of mortality or general deterioration of quality of life. To both prevent and monitor treatment of iron related disorders, we present a point of care medical device which leverages a simple smartphone camera to measure total iron concentration from a finger-prick sample. The system consists of a smartphone and an in-house developed app, a 3D printed sensing chamber and a vertical flow membrane-based sensor strip designed to accommodate 50 μl of whole blood, filter out the cellular components and carry out a colorimetric chelation reaction producing a colour change which is detected by our smartphone device. The app's accuracy and precision were assessed via comparison of the mobile app's RGB output to a reference imaging software, ImageJ for the same colorimetric sensing strip. Correlation plots resulted in slopes of 0.99 and coefficient of determination (R² = 0.99). The device was determined to have a signal to noise ratio >40 and a mean bias of 2% which both indicate high analytical accuracy and precision (in terms of RGB measurement). The smartphone device's iron concentration readout was then studied using an extensively validated laboratory developed test (LDT) for iron detection, which is an optimized spectrophotometry-based technique (this is considered the gold standard for iron quantification among LDTs). In comparison of the smartphone-based technique with the gold standard LDT, a calibration slope of 0.0004 au μg⁻¹ dL⁻¹, a correlation plot with slope of 1.09 and coefficient of determination (R²) of 0.96 and a mean bias of 5.3%, our device can accurately measure iron levels in blood. With detection times of five minutes, fingerpick sample and sensor cost less than 10 cents, the device shows great promise in being developed as the first ever commercial device for iron quantification in blood.

中文翻译：

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一种新型垂直流测定法，用于从全血中进行铁的即时测量

铁代谢紊乱是全球性流行病，影响了数亿人，并常常导致死亡率上升或生活质量普遍下降。为了预防和监测铁相关疾病的治疗，我们提供了一种护理医疗设备，该设备利用简单的智能手机摄像头来测量指尖样本中的总铁浓度。该系统由智能手机和内部开发的应用程序，3D打印的传感室和基于垂直流膜的传感器条组成，可容纳50μl全血，过滤出细胞成分并进行比色螯合反应，从而产生我们的智能手机设备检测到的颜色变化。该应用的准确性和精确度通过将移动应用程序的RGB输出与参考成像软件ImageJ（用于同一比色传感带）进行比较。相关图得出的斜率为0.99，测定系数为（R ² = 0.99）。确定该设备的信噪比> 40，平均偏差为2％，均表明分析精度和精度都很高（就RGB测量而言）。然后，使用经过广泛验证的实验室开发的铁检测测试（LDT）对智能手机设备的铁浓度读数进行了研究，这是一种基于分光光度法的优化技术（这被认为是LDT中铁定量的金标准）。与基于智能手机的技术和金标准LDT相比，校准斜率为0.0004 auμg ^-1dL ^-1是一种相关图，其斜率是1.09，测定系数（R ²）是0.96，平均偏差为5.3％，我们的设备可以准确地测量血液中的铁水平。检测时间为五分钟，指尖采样和传感器成本不到10美分，因此该设备被证明是有史以来开发的第一个用于血液中铁定量的商用设备，前景广阔。