title: Pre-bisection of a single skin biopsy does not produce technically inadequate specimens for direct immunofluorescence: a review of 3450 specimens.
abstract: BACKGROUND
  Evaluation of a potential immunobullous disorder typically requires two pieces of tissue obtained by skin biopsy: one placed in formalin for conventional microscopy and a second placed in a different transport medium suitable for direct immunofluorescence (DIF) testing. Clinical practice in this area is not standardized, with dermatologists either obtaining two biopsies or dividing (pre-bisecting) a single biopsy. Some DIF specimens are technically inadequate for interpretation of subepidermal imunobullous disorders because the basement membrane zone is not intact, but it is unknown whether pre-bisecting the tissue increases the risk of compromising the specimen.
  
  
  OBJECTIVE
  To investigate whether technically inadequate DIF specimens are associated with pre-bisection.
  
  
  METHODS
  DIF specimens were consecutively sampled from a single referral center and identified as whole (non-bisected) biopsy specimens or pre-bisected biopsy specimens. The proportion of inadequate specimens was calculated for both groups.
  
  
  RESULTS
  A total of 3450 specimens were included. The percentage of inadequate specimens was 5.072% (153/3016) for whole (non-bisected) specimens and 5.299% for pre-bisected specimens. This difference was not significant (chi square, p = 0.84). The study was sufficiently powered to detect a relative risk of 1.685.
  
  
  CONCLUSIONS
  Pre-bisection of a single skin biopsy does not significantly increase the risk of a technically inadequate specimen for direct immunofluorescence testing.
authors.affiliation: Department of Dermatology, University of California Davis School of Medicine, Sacramento, CA, USA.
authors.forename: Ern
authors.initials: E
authors.lastname: Loh
authors.forename: April W
authors.initials: AW
authors.lastname: Armstrong
authors.forename: Maxwell A
authors.initials: MA
authors.lastname: Fung
mesh_terms: D001706:Biopsy; D003581:Cytodiagnosis / Q000379:methods* / Q000592:standards; D019085:Fluorescent Antibody Technique, Direct / Q000379:methods*; D006801:Humans; D012872:Skin Diseases, Vesiculobullous / Q000175:diagnosis*; D013048:Specimen Handling
keywords: bullous pemphigoid; dermatologist; dermatopathology; immunopathology