title: Prevalence of a normal C-reactive protein with an elevated erythrocyte sedimentation rate in biopsy-proven giant cell arteritis.
abstract: OBJECTIVE
  The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are laboratory tests that have been said to have a strong correlation with a positive temporal artery biopsy in patients with suspected giant cell arteritis (GCA). Published reports suggest that the CRP is a more sensitive diagnostic indicator of GCA and can be elevated when the ESR is normal. It is also clear that the CRP and ESR can both be normal or both be elevated in patients with biopsy-proven GCA and that the CRP can be elevated when the ESR is normal. The purpose of this study was to ascertain if the CRP can be normal when the ESR is elevated in biopsy-proven GCA.
  
  
  METHODS
  Retrospective, longitudinal, comparative study.
  
  
  METHODS
  One hundred nineteen patients from 6 major tertiary-care university-affiliated medical centers.
  
  
  METHODS
  The charts from 119 patients with temporal artery biopsies positive for GCA were reviewed for age, gender, pretreatment ESR, and pretreatment CRP.
  
  
  METHODS
  The ESR in millimeters per hour Westergren was graded as normal or abnormal based on 2 validated formulas. The CRP was graded as normal or abnormal based on established criteria set forth in the literature as well as at The Johns Hopkins Hematology laboratory.
  
  
  RESULTS
  In this study, the ESR had a sensitivity of 76% to 86%, depending on which of 2 formulas were used, whereas an elevated CRP had a sensitivity of 97.5%. The sensitivity of the ESR and CRP together was 99%. Only 1 of the 119 patients (0.8%) presented with a normal ESR and normal CRP (double false negative); 2 patients (1.7%) had a normal CRP despite an elevated ESR according to both formulas.
  
  
  CONCLUSIONS
  Although most patients with GCA have both an elevated ESR and CRP, there can be nonconcordance of the 2 blood tests. Although such nonconcordance is most often a normal ESR but an elevated CRP, the finding of an elevated ESR and a normal CRP also is consistent with GCA. The use of both tests provides a slightly greater sensitivity for the diagnosis of GCA than the use of either test alone.
authors.affiliation: Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
authors.forename: Mona
authors.initials: M
authors.lastname: Parikh
authors.forename: Neil R
authors.initials: NR
authors.lastname: Miller
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Lee
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Savino
authors.forename: M Noel
authors.initials: MN
authors.lastname: Vacarezza
authors.forename: Wayne
authors.initials: W
authors.lastname: Cornblath
authors.forename: Eric
authors.initials: E
authors.lastname: Eggenberger
authors.forename: Aileen
authors.initials: A
authors.lastname: Antonio-Santos
authors.forename: Karl
authors.initials: K
authors.lastname: Golnik
authors.forename: Randy
authors.initials: R
authors.lastname: Kardon
authors.forename: Michael
authors.initials: M
authors.lastname: Wall
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism*; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D013700:Giant Cell Arteritis / Q000097:blood / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018917:Optic Neuropathy, Ischemic / Q000097:blood / Q000175:diagnosis; D011237:Predictive Value of Tests; D015995:Prevalence; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013699:Temporal Arteries / Q000473:pathology*
chemical_list: D002097:C-Reactive Protein