title: Evaluation of the C6 Lyme Enzyme Immunoassay for the Diagnosis of Lyme Disease in Children and Adolescents.
abstract: The commercially-available C6 Lyme enzyme immunoassay (EIA) has been approved to replace the standard whole-cell sonicate EIA as a first-tier test for the diagnosis of Lyme disease and has been suggested as a stand-alone diagnostic. However, the C6 EIA has not been extensively studied in pediatric patients undergoing evaluation for Lyme disease.
  
  
  
  We collected discarded serum samples from children and adolescents (aged ≤21 years) undergoing conventional 2-tiered testing for Lyme disease at a single hospital-based clinical laboratory located in an area endemic for Lyme disease. We performed a C6 EIA on all collected specimens, followed by a supplemental immunoblot if the C6 EIA result was positive but the whole-cell sonicate EIA result was negative. We defined a case of Lyme disease as either a clinician-diagnosed erythema migrans lesion or a positive standard 2-tiered serologic result in a patient with symptoms compatible with Lyme disease. We then compared the performance of the C6 EIA alone and as a first-tier test followed by immunoblot, with that of standard 2-tiered serology for the diagnosis of Lyme disease.
  
  
  
  Of the 944 specimens collected, 114 (12%) were from patients with Lyme disease. The C6 EIA alone had sensitivity similar to that of standard 2-tiered testing (79.8% vs 81.6% for standard 2-tiered testing; P = .71) with slightly lower specificity (94.2% vs 98.8% 2; P < .002). Addition of a supplemental immunoblot improved the specificity of the C6 EIA to 98.6%.
  
  
  
  For children and adolescents undergoing evaluation for Lyme disease, the C6 EIA could guide initial clinical decision making, although a supplemental immunoblot should still be performed.
authors.affiliation: Division of Emergency Medicine.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Lipsett
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston.
authors.forename: John A
authors.initials: JA
authors.lastname: Branda
authors.affiliation: Department of Laboratory Medicine, Boston Children's Hospital.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: McAdam
authors.affiliation: Division of General Pediatrics Pediatric Physicians' Organization at Children's, Brookline, Massachusetts.
authors.forename: Louis
authors.initials: L
authors.lastname: Vernacchio
authors.affiliation: Division of Emergency Medicine.
authors.forename: Caroline D
authors.initials: CD
authors.lastname: Gordon
authors.affiliation: Division of Emergency Medicine.
authors.forename: Catherine R
authors.initials: CR
authors.lastname: Gordon
authors.affiliation: Division of Emergency Medicine.
authors.forename: Lise E
authors.initials: LE
authors.lastname: Nigrovic
mesh_terms: D000293:Adolescent; D000907:Antibodies, Bacterial / Q000097:blood; D025065:Borrelia burgdorferi / Q000276:immunology; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods* / Q000592:standards*; D008193:Lyme Disease / Q000175:diagnosis*; D008297:Male; D012680:Sensitivity and Specificity
chemical_list: D000907:Antibodies, Bacterial
keywords: C6; Lyme disease; Lyme disease diagnostics; pediatrics