Evaluation of the pulmonary embolism rule out criteria (PERC rule) in children evaluated for suspected pulmonary embolism.

BACKGROUND: The pulmonary embolism rule out criteria (PERC) reliably predicts a low probability of PE in adults. We examine the diagnostic accuracy of the objective components of the PERC rule in children previously tested for PE.

METHODS: Children aged 5-17 who had a D-dimer or pulmonary vascular imaging ordered from 2004 to 2014 in a large multicenter hospital network were identified by query of administrative databases. Using explicit, predefined methods, trained abstracters selected charts of children clearly tested for PE, collected the 8 objective variables for PERC, and determined PE criterion standard status (image or autopsy confirmed PE or deep vein thrombosis within 30 days by query of the Indiana Network for Patient Care (INPC)).

RESULTS: We identified 543 patients, including 56 (10.3%, 95% CI: 7.8-13.1%) who were PE+, with a mean and median age of 15 years. All 8 objective criteria from PERC were negative in 170 patients (31%), including one with PE (false negative rate 0.6%, 0-3.2%). Diagnostic sensitivity and specificity were 98.2% (90.5-100%), and 34.7 (30.5-39.1%), respectively, leading to a likelihood ratio negative = 0.05 (0.1-0.27). When treated as a diagnostic test based upon sum of criteria positive, PERC had good discrimination between PE+ vs PE- with an area under receiver operating characteristic curve 0.81 (0.75-0.86).

CONCLUSIONS: In this sample of children and teenagers with suspected PE, the PERC rule was negative in 31%, and demonstrated good overall diagnostic accuracy, including a low false negative rate. These data support the need for a large, prospective diagnostic validation study of PERC in children.