Red blood cells (RBC) can be present in urine even when they are not visible to a person. Also known as hematuria, RBC in urine can indicate an infection, kidney disease, and other health conditions.

RBC:TP = Hyperpolarized 129Xenon MRI lung ratio of red blood cell spectral peak to tissue phase spectral peak MRI Finds Lung Abnormalities in Non-Hospitalized Long COVID Patients MRI Finds Lung ...