title: Serum biomarkers for identifying acute chest syndrome among patients who have sickle cell disease and present to the emergency department.
abstract: OBJECTIVE
  To compare the accuracy of biomarkers for identifying acute chest syndrome (ACS) in patients with sickle cell disease presenting to a pediatric emergency department (ED).
  
  
  METHODS
  We conducted a 13-month-long (2002-2003) cohort study with nested case-control in patients with sickle cell disease presenting to the pediatric ED with vaso-occlusive crises or fever in which we compared levels of secretory phospholipase A2 (sPLA2), endothelin-1, interleukin-6 (IL-6), and peripheral white blood cell count (WBC) in cases that were complicated by ACS and in control subjects with uncomplicated illnesses. For diagnosis, a test was considered to be accurate when the area under its receiver operator characteristic curve (AUC) was >0.70. Laboratory tests with AUC values > or =0.70 were entered into a binary recursive partitioning model for diagnosis.
  
  
  RESULTS
  For the period of study, samples from 72 visits were obtained from 51 patients who presented with vaso-occlusive crises (range: 1-4 visits per patient; 15 were enrolled more than once). ACS complicated 19 of 72 visits (26%, 95% confidence interval: 17%-38%). At an AUC value of 0.79, only the sPLA2 test was accurate for diagnosing ACS. AUC values for peripheral WBC, endothelin-1, and IL-6 were 0.68, 0.51, and 0.52, respectively. Binary recursive partitioning retained only sPLA2 at a cutoff of 13.7 ng/mL to be accurate for diagnosis. This cutoff had a sensitivity of 74% (14 of 19), a specificity of 87% (46 of 53), a positive likelihood ratio of 5.6, and a negative likelihood ratio of 0.18.
  
  
  CONCLUSIONS
  Secretory phospholipase A2 but not endothelin-1, IL-6, or WBC is an accurate test for identifying present or incipient ACS in young patients who present to the ED with sickle cell pain crises.
authors.affiliation: Division of Emergency Medicine, Department of Medicine, Children's Hospital, Columbus, Ohio 43205, USA. naprawaj@pediatrics.ohio-state.edu
authors.forename: James T
authors.initials: JT
authors.lastname: Naprawa
authors.forename: Bema K
authors.initials: BK
authors.lastname: Bonsu
authors.forename: Deborah G
authors.initials: DG
authors.lastname: Goodman
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ranalli
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000097:blood / Q000150:complications*; D019540:Area Under Curve; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain; D002648:Child; D019332:Endothelin-1 / Q000097:blood; D005260:Female; D006801:Humans; D015850:Interleukin-6; D007958:Leukocyte Count; D008171:Lung Diseases / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D010741:Phospholipases A / Q000097:blood*; D054467:Phospholipases A2; D012680:Sensitivity and Specificity; D013577:Syndrome
chemical_list: D015415:Biomarkers; D019332:Endothelin-1; D015850:Interleukin-6; D010741:Phospholipases A; D054467:Phospholipases A2