Instrument and method for non-invasive in vivo testing for body fluid

Abstract

There is disclosed herein a nuclear magnetic resonance apparatus for testing body fluids for a constituent, for example, blood for glucose. The apparatus includes a principal magnet, a magnetizable coil, and a circuit for energizing the coil for energizing and realigning molecules and detecting changes resulting from relaxation of said field and analyzing said changes. The apparatus is compact and adapted to receive and test an extremity or vessel carrying a body fluid. The coil is constructed to be positioned adjacent the extremity or vessel to be tested. Circuit means are provided for energizing the coil to energize and realign molecules adjacent said coil, so as to permit molecules adjacent said coil to assume an aligned position and for sensing changes in position when the coil is deenergized, which is indicated by spectra having peaks corresponding to various molecular bonds. The circuit also includes means for comparing the actual value of a peak for a first constituent to a predetermined value for the peak of said first constituent and determining the actual value of a second constituent from a predetermined relationship between the values of the peaks for the first and second constituents. Specifically, predetermined water and glucose peaks are compared with the measured water and glucose peaks for determining the measured glucose concentration.