A versatile electrophoresis-based self-test platform.

This paper reports on recent research creating a family of electrophoresis-based point of care devices for the determination of a wide range of ionic analytes in various sample matrices. These devices are based on a first version for the point-of-care measurement of Li(+), reported in 2010 by Floris et al. (Lab Chip 2010, 10, 1799-1806). With respect to this device, significant improvements in accuracy, precision, detection limit, and reliability have been obtained especially by the use of multiple injections of one sample on a single chip and integrated data analysis. Internal and external validation by clinical laboratories for the determination of analytes in real patients by a self-test is reported. For Li(+) in blood better precision than the standard clinical determination for Li(+) was achieved. For Na(+) in human urine the method was found to be within the clinical acceptability limits. In a veterinary application, Ca(2+) and Mg(2+) were determined in bovine blood by means of the same chip, but using a different platform. Finally, promising preliminary results are reported with the Medimate platform for the determination of creatinine in whole blood and quantification of both cations and anions through replicate measurements on the same sample with the same chip.

Point of care creatinine measurement for diagnosis of renal disease using a disposable microchip.

A point-of-care device for the determination of elevated creatinine levels in blood is reported. This device potentially offers a new and simple clinical regime for the determination of creatinine that will give huge time savings and removal of several steps of determination. The test employs a disposable prefilled microchip and the handheld Medimate Multireader®. By optimizing the analytical conditions it was found that the LOD of the proposed method was 87 µM creatinine, close to the normal human serum levels that are in the range of 60 to 100 µM. A statistical analysis of the residual shows a normal distribution, indicating the absence of systematic errors in the proposed method. The test can be used to distinguish patients with renal insufficiency (creatinine levels >100 µM) from healthy persons. Long-term monitoring could furthermore distinguish between acute renal failure and chronic kidney disease by the rate of creatinine concentration rise.

A prefilled, ready-to-use electrophoresis based lab-on-a-chip device for monitoring lithium in blood.

We present the Medimate Multireader, the first point-of-care lab on a chip device that is based on capillary electrophoresis. It employs disposable pre-filled microfluidic chips with closed electrode reservoirs and a single sample opening. Several technological innovations allow operation with closed reservoirs, which is essential for reliable point-of-care operation. The chips are inserted into a hand-held analyzer. In the present application, the device is used to measure the lithium concentration in blood. Lithium is quantified by conductivity detection after separation from other blood ions. Measurements in patients show good accuracy and precision, and there is no difference between the results obtained by skilled and non-skilled operators. This point-of-care device shows great promise as a platform for the determination of ionic substances in diagnostics or environmental analysis.