Thus, it has been found to affect people of African and Greek descent. References


== External links ==
Pulmonary embolism rule-out criteria
The pulmonary embolism rule-out criteria (PERC) helps assess people in whom pulmonary embolism is suspected, but unlikely. Unlike the Wells score and Geneva score, which are clinical prediction rules intended to risk stratify people with suspected PE, the PERC rule is designed to rule out the risk of PE in people when the physician has already stratified them into a low-risk category.People in this low risk category without any of these criteria may undergo no further testing for PE: low oxygen saturations – SaO2 <95%, unilateral leg swelling, coughing up blood, prior DVT or PE, recent surgery or trauma, age >50, hormone use, fast heart rate. The rationale behind this decision is that further testing (specifically CT angiogram of the chest) may cause more harm (from radiation exposure and contrast dye) than the risk of PE. The PERC rule has a sensitivity of 97.4% and specificity of 21.9% with a false negative rate of 1.0% (16/1666). Blood tests
In people with a low or moderate suspicion of PE, a normal D-dimer level (shown in a blood test) is enough to exclude the possibility of thrombotic PE, with a three-month risk of thromboembolic events being 0.14%. D-dimer is highly sensitive but not specific (specificity around 50%). In other words, a positive D-dimer is not synonymous with PE, but a negative D-dimer is, with a good degree of certainty, an indication of absence of a PE. A low pretest probability is also valuable in ruling out PE.