NMR systems and methods for the rapid detection of analytes

A method of monitoring one or more nucleic acid analytes in a whole blood sample derived from a patient for the diagnosis, management, or treatment of a medical condition in the patient, wherein the one or more nucleic acid analytes have been amplified in the whole blood sample, the method comprising:

• (a) combining with the sample from 1×106 to 1×1013 magnetic particles per milliliter of the sample, wherein the magnetic particles have a mean diameter of from 700 nm to 950 nm and a T2 relaxivity per particle of from 1×109 to 1×1012 mM−1s−1, and wherein the magnetic particles have binding moieties on their surfaces, the binding moieties operative to alter the specific aggregation of the magnetic particles in the presence of the one or more nucleic acid analytes or a multivalent binding agent;
• (b) placing the sample in a device, the device comprising a support defining a well for holding the sample comprising the magnetic particles and the one or more nucleic acid analytes, and having an RF coil disposed about the well, the RF coil configured to detect a signal produced by exposing the sample to a bias magnetic field created using one or more magnets and an RF pulse sequence;
• (c) exposing the sample to a bias magnetic field and an RF pulse sequence;
• (d) following step (c), measuring the signal, thereby monitoring the one or more nucleic acid analytes;
• and
• (e) using the result of step (d) to diagnose, manage, or treat the medical condition.