An embolism may be made from any one of numerous materials that may find itself in a blood vessel, including a piece of a thrombus, known as a thromboembolism, air from an intravenous catheter, fat globules from bone marrow, amniotic fluid during birth.

Three important clinical manifestations that may be caused by paradoxical embolism include a stroke, migraine, and acute myocardial infarction, also known as a heart attack.

[10] Additionally, if a paradoxical embolism is suspected in a patient, findings consistent with a congenital heart defect that may lead to right-to-left shunting can be evaluated.

These include digital clubbing due to chronic hypoxemia in distal extremities or a widely-split S2, a pathological heartbeat pattern where the second heart sound has two components.

It is essential to discuss if the patient has personal or family history of a patent foramen ovale or other congenital heart disease that may have allowed an embolus into arterial circulation.

These tests measure how quickly a blood clot can form and may include PT, PTT, INR, and Protein C and S levels.

Ultrasound, MRI imaging, or CT scans of the lower extremities help to identify a possible DVT, which provides evidence that an emboli may have come from venous circulation.

The use of MRI to detect cardiac shunts is "controversial" and that the use of CT is not recommended due to exposure to ionizing radiation and lack of functional imaging.

Following a valsalva maneuver, pressure increases in the right heart, deoxygenated blood is shunted into arterial circulation, and a decrease in oxygen saturation can then be measured in the capillaries of the ear.

[7] Current recommendation suggest that the two major goals of treatment include medical management of the thrombotic event to help prevent further thrombus/embolus formation and closure of the patent foramen ovale or other route that let to a pardoxical embolism.

[7] Although closure of a patent foramen ovale or atrial septal defect theoretically removes the pathway for an arterial embolus to enter venous circulation and cause a paradoxical embolism, data suggests that closing intracardiac shunts is no more effective than medical management alone in preventing strokes.