title: Application of a combined protocol for rational request and utilization of antibody assays improves clinical diagnostic efficacy in autoimmune rheumatic disease.
abstract: BACKGROUND
  Because of a marked increase in the number of requests for antinuclear antibodies, anti-extractable nuclear antigen antibodies, and anti-double-stranded DNA antibodies for the diagnosis of autoimmune rheumatic disease, guidelines have been proposed for their appropriate use.
  
  
  OBJECTIVE
  To evaluate in terms of clinical efficacy and cost-benefit ratio the outcome of applying a protocol for the diagnosis of autoimmune rheumatic disease.
  
  
  METHODS
  A diagnostic protocol for the rational utilization of second-level tests (anti-extractable nuclear antigen antibodies and anti-double-stranded DNA antibodies) was applied at Hospital Polyclinic beginning January 2004. The appropriateness of 685 consecutive requests received at the clinical pathology laboratory from January to June 2004 was assessed. Patients who underwent these laboratory tests were followed up for 12 months after blood sample drawing.
  
  
  RESULTS
  Introduction of the protocol led to a significant reduction in the number of second-level tests prescribed (27.9% vs 49.5% for anti-extractable nuclear antigen antibodies; 27.5% vs 56.6% for anti-double-stranded DNA antibodies). After the period of observation, none of the 163 patients who had negative results on the first-level test and were asymptomatic, for whom second-level tests had not therefore been performed, were found to have autoimmune rheumatic disease. In 90.5% (77/85) of patients positive for the second-level tests, clinical confirmation of autoimmune rheumatic disease was obtained.
  
  
  CONCLUSIONS
  Not only did application of the diagnostic protocol reduce the number of second-level tests performed but it also increased their specificity. Our data thus indicate that the use of shared guidelines by clinical and laboratory specialists yields satisfactory results.
authors.affiliation: Department of Clinical Pathology I, Hospital Polyclinic of Bari, Bari, Italy. mtampoia@libero.it
authors.forename: Marilina
authors.initials: M
authors.lastname: Tampoia
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Brescia
authors.forename: Antonietta
authors.initials: A
authors.lastname: Fontana
authors.forename: Antonietta
authors.initials: A
authors.lastname: Zucano
authors.forename: Luigi Francesco
authors.initials: LF
authors.lastname: Morrone
authors.forename: Nicola
authors.initials: N
authors.lastname: Pansini
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D000974:Antibodies, Antinuclear / Q000097:blood*; D034961:Antigens, Nuclear / Q000276:immunology; D001327:Autoimmune Diseases / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D002985:Clinical Protocols; D003362:Cost-Benefit Analysis; D004247:DNA / Q000276:immunology; D006801:Humans; D007159:Immunologic Tests / Q000191:economics / Q000379:methods*; D017410:Practice Guidelines as Topic; D012216:Rheumatic Diseases / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D012680:Sensitivity and Specificity
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000974:Antibodies, Antinuclear; D034961:Antigens, Nuclear; D004247:DNA