title: [Comparison of quantitative results among two automated Rapid Plasma Reagin (RPR) assays and a manual RPR test].
abstract: BACKGROUND
  We compared two automated Rapid Plasma Reagin (RPR) assay kits with a manual RPR assay kit to evaluate the possibility of using the two automated RPR assays as an alternative to the manual RPR assay for a quantitative monitoring.
  
  
  METHODS
  One hundred eighty-five samples were analyzed, including 16 sera from patients with primary, secondary, and latent syphilis. Measured RPR unit (R.U.) values of two automated RPR assay kits, Mediace RPR (Sekisui Chemical Co., Ltd, Japan) and HBi Auto RPR (HBI Co., Ltd, Korea), were compared with the RPR titers of Macro-Vue RPR card test (Becton Dickinson BD Microbiology systems, USA). As a confirmatory test, Anti-Treponema pallidum EUROLINE WB (IgG) and Anti-Treponema pallidum EUROLINE WB (IgM) (Euroimmun, Germany) were used.
  
  
  RESULTS
  There was a prozone effect with Mediace RPR at RPR titer (card test) of 1:16, but not with HBi Auto RPR. The R.U. values of the two automated RPR assays did not show proportional increase to the RPR titer. Agreement between manual RPR and two automated RPR assay kits, Mediace RPR assay and HBi Auto RPR assay, were 83.8% and 83.2%, respectively.
  
  
  CONCLUSIONS
  The two automated RPR assay kits could not be used as an alternative to manual RPR test for quantitative analysis of RPR titer. As Mediace RPR shows a prozone effect at relatively low RPR titer, caution is needed in the interpretation of the measured values.
authors.affiliation: Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yeong Sic
authors.initials: YS
authors.lastname: Kim
authors.forename: Jehoon
authors.initials: J
authors.lastname: Lee
authors.forename: Hae Kyung
authors.initials: HK
authors.lastname: Lee
authors.forename: Hyunjung
authors.initials: H
authors.lastname: Kim
authors.forename: Hi Jeong
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Ki Ouk
authors.initials: KO
authors.lastname: Min
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Seo
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Kim
mesh_terms: D001331:Automation; D005260:Female; D006801:Humans; D008297:Male; D011933:Reagent Kits, Diagnostic; D011935:Reagins / Q000097:blood*; D012680:Sensitivity and Specificity; D013587:Syphilis / Q000175:diagnosis*; D013588:Syphilis Serodiagnosis / Q000379:methods*; D014210:Treponema pallidum
chemical_list: D011933:Reagent Kits, Diagnostic; D011935:Reagins