title: Temporal artery biopsy for diagnosing giant cell arteritis: the longer, the better?
abstract: OBJECTIVE
  To investigate the relation between temporal artery biopsy (TAB) length and diagnostic sensitivity for giant cell arteritis.
  
  
  METHODS
  Histological TAB reports generated from four hospital pathology departments were reviewed for demographics, histological findings, and formalin fixed TAB lengths. A biopsy was considered positive for giant cell arteritis if there was a mononuclear cell infiltrate predominating at the media-intima junction or in the media.
  
  
  RESULTS
  Among 1821 TAB reports reviewed, 287 (15.8%) were excluded because of missing data, sampling errors, or age < 50 years. Mean TAB length of the 1520 datasets finally analysed (67.2% women; mean (SD) age, 73.1 (10.0) years) was 1.33 (0.73) cm. Histological evidence of giant cell arteritis was found in 223 specimens (14.7%), among which 164 (73.5%) contained giant cells. Statistical analyses, including piecewise logistic regression, identified 0.5 cm as the TAB length change point for diagnostic sensitivity. Compared with TAB length of < 0.5 cm, the respective odds ratios for positive TAB without and with multinucleated giant cells in samples > or = 0.5 cm long were 5.7 (95% confidence interval, 1.4 to 23.6) and 4.0 (0.97 to 16.5).
  
  
  CONCLUSIONS
  A fixed TAB length of at least 0.5 cm could be sufficient to make a histological diagnosis of giant cell arteritis.
authors.affiliation: Department of Internal Medicine, Hôpital Cochin, 27 rue du Faubourg Saint-Jacques, 75679 Paris Cedex 14, France. alfred.mahr@cch.aphp.fr
authors.forename: A
authors.initials: A
authors.lastname: Mahr
authors.forename: M
authors.initials: M
authors.lastname: Saba
authors.forename: M
authors.initials: M
authors.lastname: Kambouchner
authors.forename: M
authors.initials: M
authors.lastname: Polivka
authors.forename: M
authors.initials: M
authors.lastname: Baudrimont
authors.forename: I
authors.initials: I
authors.lastname: Brochériou
authors.forename: J
authors.initials: J
authors.lastname: Coste
authors.forename: L
authors.initials: L
authors.lastname: Guillevin
mesh_terms: D000368:Aged; D001706:Biopsy / Q000379:methods; D005260:Female; D013700:Giant Cell Arteritis / Q000473:pathology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D010337:Pathology Department, Hospital; D012189:Retrospective Studies; D012219:Rheumatology; D012680:Sensitivity and Specificity; D013699:Temporal Arteries / Q000473:pathology*