Pulmonary thrombus emboli (PTE) have a wide clinical spectrum, from asymptomatic small PTE to life threatening one, which may cause cardiogenic shock. It is classified as acute/chronic and massive/sub massive. PTE risk factors and relative causes to elevate its mortality are present in this review article.At last we have a brief recommendation for treatment. There are several diagnosing test such as D-dimer, echocardiography, electrocardiography, brain natriuretic peptide, laboratory tests, chest x ray, ultrasound and pulmonary angiography which are different in specificity and sensitivity. Finally in diagnostic approach we explain relative studies to Wells rule, Geneva rule, pulmonary embolism severity index and pulmonary embolism rule out criteria.
Key Words: Pulmonary emboli, prediction rules, pulmonary embolism rule-out criteria.