System and method for rapid assessment of renal function

A sublingual device for use in connection with a monitoring device for diagnosing a patient's renal function using a first tracer agent, wherein the first tracer agent is at least substantially cleared by healthy renal function and emits a first fluorescent light at a first emission wavelength in response to excitation by a first excitation light at a first excitation wavelength, comprising:

• a mouth-engaging member configured to be engaged by a mouth of the patient and a tongue-engaging member extending from the mouth-engaging member, wherein the tongue-engaging member includes a base configured to be positioned adjacent to a sublingual portion of a patient's tongue, and wherein the base is curved such that a distal portion of the base extends below a proximal portion of the base;
• a first sensor assembly including a first emitter and a first receiver supported by the base;
• wherein the first emitter is configured to emit the first excitation light onto a first sublingual monitoring site of the sublingual portion of the patient's tongue to excite the first tracer agent at the first sublingual monitoring site when the base is positioned adjacent to the sublingual portion of the patient's tongue;
• and
• wherein the first receiver is configured to receive the first fluorescent light representative of a patient's renal function that is emitted from the first tracer agent from the first sublingual monitoring site of the sublingual portion of the patient's tongue when the base is positioned adjacent to the sublingual portion of the patient's tongue;
• wherein:
• the first sublingual monitoring site includes a first sublingual excitation site and a first sublingual detection site;
• the first emitting means is configured to emit the first excitation light onto the first sublingual excitation site when the base is positioned adjacent to the sublingual portion of the patient's tongue;
• the first receiver is configured to receive the first fluorescent light from the first sublingual detection site when the base is positioned adjacent to the sublingual portion of the patient's tongue;
• and
• the first sublingual detection site is positioned downstream from the first sublingual excitation site according to the flow direction of the blood in a first sublingual vessel encompassed by the first sublingual monitoring site.