Methods for detecting disease in a patient are disclosed. The methods involve administering to the patient a quantum dot-analyte conjugate, which includes an analyte that binds to a marker for the disease in the patients gastrointestinal tract. The analyte is conjugated to a quantum dot having a characteristic emission wavelength. Using an endoscopic modality, a physician can illuminate portions of the patients gastrointestinal tract and detect the presence of the marker based on emission of the quantum dot. Also disclosed are methods of predicting a response to a treatment in a patient.
