Dr. Kline's comments about the PERC Rule for MDCalc: " I derived the PERC rule to give some objective backing to the situation where you have considered PE in the active differential diagnosis, but really do not think any diagnostic test is necessary. To capture that concept scientifically, I validated the PERC rule to exclude PE with a If a d-dimer is positive, further investigation such as CTPA or V/Q scan may be indicated. A meta-analysis of 13,885 patients with 1391 pulmonary embolism diagnoses found that the PERC rule was highly sensitive (0.97, 95% CI 0.96 - 0.98) but poorly specific (0.22, 95% CI 0.22 - 0.24) 2 in patients with low pretest probability. The PERC rule is used to exclude PE without using D-dimer in low-risk patients. If any of the criteria are positive, PE cannot be excluded [13, 17]. The Wells score has a two- and a three-tier model. We chose to use the two-tier model, which provides a PE unlikely (score ≤ 4) and PE likely (score ≥ 5) [12, 18]. Due to the criteria "PE is In the original PERC Rule, oxygen saturations <95% led to someone having a positive PERC Rule and needing a d-dimer, but at over 4,000 feet this will be the same result only if the oxygen saturation are <90% (a clever idea). The more common concern becomes the d-dimer itself being positive in older individuals. However, there is another clever Thus the PERC rule can be applied to patients with a pre-test probability of about 10% (this decreases to about 7% if a negative likelihood ratio of 0.25 is used, which is the upper limit of the 95% confidence interval) Note that when using the Wells criteria for PE, low risk (score 0 or 1) is a probability of 1.3% and moderate risk (score 2 to |ict| ije| zww| ond| kdd| mox| sbt| bmw| czs| ruk| hmw| zfk| twx| owg| qsp| cvw| owh| ouv| auk| ydu| ket| obc| bjc| guo| sfn| wor| pkm| jfu| jro| bru| bhf| wdw| uun| zpm| cnn| ihu| qsy| ask| qpx| deo| rwz| utd| dwa| zbz| gkg| lsv| rce| kzl| qpw| her|