Method of testing blood

A method of testing blood, comprising steps of:

• providing a testing substrate, comprising a substrate, a quantum well structure, a first-type doped semiconductor layer, a testing surface, and a plurality of nanometer metal particles located on said testing surface;
• disposing a blood sample on said testing substrate, said blood sample comprising a plurality of blood cells, the blood plasma, and a plurality of target substances;
• said testing substrate separating said blood sample to a first part and a second part, said first part comprising said plurality of blood cells, said blood plasma, and a portion of said plurality of target substrates, said second part comprising a portion of said plurality of blood cells and a portion of said plurality of target substances, with the number of said plurality of blood cells in said second part greater than the number of said plurality of blood cells in said first part;
• using a spectrometer to detect the Raman spectrum of said first part or said second part on said testing substrate for measuring the characteristics of said plurality of target substances and generating a target spectrum;
• and
• a control unit comparing said target spectrum and a preset spectrum for generating a testing result.