  We have conducted a pilot clinical study to not only investigate the THz
spectra of ex-vivo fresh human whole blood of 28 patients following 8-hours
fasting guideline, but also to find out the critical blood ingredients of which
the concentration dominantly affects those THz spectra. A great difference
between the THz absorption properties of human blood among different people was
observed, while the difference can be up to ~15% of the averaged absorption
coefficient of the 28 samples. Our pilot clinical study indicates that
triglyceride and red blood cell were two dominant factors to have significant
clinically defined negative correlation to the sub-THz absorption coefficients.
