By MRM-LRP, unique peptides of GFAP, as well as APOA1, can be detected at the same time, and a combination of low APOA1-UP level and normal level of GFAP-UP would suggest a diagnosis of ischemic stroke, whereas a combination of normal APOA1-UP levels and a high level of GFAP-UP would indicate a diagnosis of hemorrhagic stroke. The gene discussed is UPP1; the disease is ischemic stroke.