Abstract: Methods are provided for forming a complex comprising an analyte (or an analyte analog) from a blood-derived sample and labeling substances, and separating the complex from excess labeling substances and coexisting substances from the blood-derived sample, in a rapid, simple, convenient, and highly precise isotachophoresis (ITP) process by adding 2-(N-morpholino)ethane sulfonate (MES) salt and/or glutamate salt to the ITP sample. Methods are also provided for measuring the analyte in blood-derived samples with high precision and high sensitivity, based on the amount of the complex separated or the amount of uncomplexed labeling substance-containing molecules.

Abstract: Methods are provided for forming a complex comprising an analyte (or an analyte analogue) from a blood-derived sample and labeling substances, and separating the complex from excess labeling substances and coexisting substances from the blood-derived sample, in a rapid, simple, convenient, and highly precise isotachophoresis (ITP) process by adding 2-(N-morpholino)ethane sulfonate (MES) salt and/or glutamate salt to the ITP sample. Methods are also provided for measuring the analyte in blood-derived samples with high precision and high sensitivity, based on the amount of the complex separated or the amount of uncomplexed labeling substance-containing molecules.

Abstract: Methods are provided for forming a complex comprising an analyte (or an analyte analogue) from a blood-derived sample and labeling substances, and separating the complex from excess labeling substances and coexisting substances from the blood-derived sample, in a rapid, simple, convenient, and highly precise isotachophoresis (ITP) process by adding 2-(N-morpholino)ethane sulfonate (MES) salt and/or glutamate salt to the ITP sample. Methods are also provided for measuring the analyte in blood-derived samples with high precision and high sensitivity, based on the amount of the complex separated or the amount of uncomplexed labeling substance-containing molecules.

Abstract: Problems to be Solved There is provided a method for separating the complex containing the analyte (or the analogue) in the blood-derived sample and the labeling substances, etc., and coexisting substances in a blood-derived sample, rapidly, simply and conveniently and in high precision by a isotachophoresis (ITP); and a measuring method for the analyte in said sample in high precision and in high sensitivity, based on amount of the complex separated or amount of the free labeling substance-containing molecules, which were not involved in formation of said complex.