title: Diagnostic accuracy and prognostic utility of D Dimer in acute appendicitis in children.
abstract: The objective was to determine the uselfulness of D Dimer (DD) as a diagnostic or prognostic marker in acute appendicitis (AA) in children using a prospective observational study in the pediatric emergency department of a tertiary hospital. We enrolled 135 patients aged 1-16 years presenting with abdominal pain consistent with AA, who required laboratory studies. We analyzed clinical, analytical variables and histopathology findings (when they underwent surgery). Statistical analysis was conducted using SPSS. 38.5% of the children were clinically diagnosed with AA (n = 52), confirmed by pathology in 51 patients. 55.8% were gangrenous appendicitis. Leucocyte count, C-reactive protein (CRP), and DD were higher in the AA group and in the gangrenous appendicitis group (p < 0.05), with highest values of DD in the gangrenous group. The area under the receiving operating characteristics (ROC) curve for DD in the diagnosis of AA is 0.66 (95% CI 0.56-0.75). For DD cut-off point of 230 ng/mL, sensitivity (Se) was 0.40, specificity (Sp) 0.80, positive predictive value (PPV) 0.57, and negative predictive value (NPV) 0.66. The area under the ROC curve for DD in children with gangrenous appendicitis is 0.93 (95% CI 0.87-1). A DD cut-off point of 230 ng/mL exhibited: Se = 0.69, Sp = 1, PPV = 1 and NPV = 0.72.
  
  
  CONCLUSIONS
  DD levels increase in patients with AA. Although it does not constitute a useful diagnostic marker, it could be a good prognostic marker.
authors.affiliation: Department of Pediatrics, Hospital General Universitario Gregorio Marañón, Madrid, Spain. juliecayrol@gmail.com.|Hospital Materno-Infantil Gregorio Marañón, Calle O'Donnell 48-50, 28009, Madrid, Spain. juliecayrol@gmail.com.
authors.forename: Julie
authors.initials: J
authors.lastname: Cayrol
authors.affiliation: Department of Pediatrics, Division of Emergency Medicine, Hospital General Universitario Gregorio Marañón, Madrid, Spain. c.miguez09@gmail.com.
authors.forename: Maria Concepción
authors.initials: MC
authors.lastname: Miguez
authors.affiliation: Department of Nursing, Pediatrics, Emergency Medicine, Hospital General Universitario Gregorio Marañón, Madrid, Spain. g.guerrero13@gmail.com.
authors.forename: Gloria
authors.initials: G
authors.lastname: Guerrero
authors.affiliation: Department of Pediatrics, Hospital General Universitario Gregorio Marañón, Madrid, Spain. cristina_ts@hotmail.com.
authors.forename: Cristina
authors.initials: C
authors.lastname: Tomatis
authors.affiliation: Department of Pediatric Surgery, Hospital General Universitario Gregorio Marañón, Madrid, Spain. isabelsimal@gmail.com.
authors.forename: Isabel
authors.initials: I
authors.lastname: Simal
authors.affiliation: Department of Pediatrics, Division of Emergency Medicine, Hospital General Universitario Gregorio Marañón, Madrid, Spain. rafamaranonpar@gmail.com.
authors.forename: Rafael
authors.initials: R
authors.lastname: Marañón
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D001064:Appendicitis / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D007223:Infant; D007958:Leukocyte Count; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D002097:C-Reactive Protein
keywords: Acute abdominal pain; Appendicitis; D-Dimer; Laboratory marker; Pediatric emergency; Prognostic marker