title: Different free prostate-specific antigen to total prostate-specific antigen ratios using three detecting systems.
abstract: BACKGROUND
  Prostate-specific antigen (PSA) is used as an indicative marker of a pathologic condition of the prostate, and the ratio of free PSA (fPSA) to total PSA (tPSA) helps to distinguish benign prostatic hyperplasia (BPH) from prostate cancer (PCa). In this study, we present some reversed ratios of fPSA to tPSA and analyze the possible mechanism.
  
  
  METHODS
  Using the UniCel DxI800 Access Immunoassay System, eight reversed fPSA to tPSA ratios were obtained, and then these samples were retested with an Abbott Architect i2000 Immunoassay Analyser and Cobas e602.
  
  
  RESULTS
  Four of the eight reversed ratios kept a ratio >1 using Abbott Architect i2000, and seven of them turned into a ratio <1 using Cobas e602.
  
  
  CONCLUSIONS
  In consideration of the assay these three detecting systems apply, the possible reason of the reversed ratios can be heterophile antibodies. To get accurate reason, further study is required.
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.|Department of Laboratory Medicine, The Oriental and Foreign Related Hospital, Lianyungang, China.
authors.forename: Hui-Qing
authors.identifier: http://orcid.org/0000-0002-9117-1379
authors.initials: HQ
authors.lastname: Huang
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Hua-Guo
authors.initials: HG
authors.lastname: Xu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood / Q000737:chemistry; D001774:Blood Chemical Analysis / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood* / Q000737:chemistry; D011470:Prostatic Hyperplasia; D011471:Prostatic Neoplasms
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen
keywords: immunoenzymatic assay; prostate-specific antigen; reversed ratio