Molecular diagnosis based on cfRNA refers to the use of cell-free RNA (cfRNA) in blood or other body fluids as biomarkers to detect and diagnose the status, progression and prognosis of various diseases.cfRNA is a dynamic, tissue-specific transcript that reflects cell state and function and can be accessed in a non-invasive manner. Case of molecular diagnosis based on cfRNA: Non-invasive prenatal testing (NIPT): through the analysis of fetal cfRNA in the blood of pregnant women, fetal chromosomal abnormalities, gene deletions or repeats, single gene genetic diseases, etc.; Early screening and diagnosis of tumors: By analyzing the tumor cfRNA in the blood of patients, the tumor mutation, copy number variation, gene fusion and methylation can be detected, so as to realize the early detection, molecular classification and treatment guidance of tumors; Immune system monitoring: by analyzing the immune cell cfRNA in the blood, the activity, balance and tolerance of the immune system can be assessed, so as to monitor autoimmune diseases, organ transplant rejection, infectious diseases, etc.; Nervous system monitoring: by analyzing the nerve cell cfRNA in the blood, it can reflect the function and damage of the nervous system, so as to monitor neurodegenerative diseases, stroke, traumatic brain injury, etc.