title: Capillary versus aspiration biopsy: effect of needle size and length on the cytopathological specimen quality.
abstract: OBJECTIVE
  To test the value of the nonaspiration, or capillary, biopsy technique by experimental comparison with the conventional fine-needle aspiration technique using various needle gauges and lengths.
  
  
  METHODS
  On fresh hepatic and renal tissue from five autopsies, multiple biopsy specimens were taken with 20, 22, and 23-gauge Chiba needles of 5, 10, 15, and 20-cm length, using the aspiration technique and the capillary technique. The resultant specimens were graded on the basis of a grading scheme by a cytopathologist who was blinded to the biopsy technique.
  
  
  RESULTS
  The capillary technique obtained less background blood or clot which could obscure diagnostic tissue, although not significantly different from the aspiration technique (p = 0.2). However, for the amount of cellular material obtained, retention of appropriate architecture, and mean score, the capillary technique performed statistically worse than aspiration biopsy (p < 0.01). In addition, with decreasing needle caliber (increasing needle gauge) and increasing length, the capillary biopsy was inferior to the aspiration biopsy.
  
  
  CONCLUSIONS
  The capillary biopsy technique is inferior to the aspiration technique according to our study. When the capillary technique is to be applied, preference should be given to larger caliber, shorter needles.
authors.affiliation: Department of Radiology, Penn State University, P.O. Box 850, Hershey, PA 17033, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Hopper
authors.forename: R T
authors.initials: RT
authors.lastname: Grenko
authors.forename: A I
authors.initials: AI
authors.lastname: Fisher
authors.forename: T R
authors.initials: TR
authors.lastname: TenHave
mesh_terms: D001707:Biopsy, Needle / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D001769:Blood; D001777:Blood Coagulation; D002197:Capillary Action; D004867:Equipment Design; D006801:Humans; D007668:Kidney / Q000473:pathology; D008099:Liver / Q000473:pathology; D016015:Logistic Models; D009339:Needles; D016037:Single-Blind Method