title: Modified assay of prostate-specific antigen with a detection limit < 0.01 microgram/L.
abstract: We modified the Hybritech Tandem-E prostate-specific antigen (PSA) assay by increasing the sample volume, increasing enzyme-substrate incubation time, and using diethanolamine buffer. Our modified method has a detection limit of 0.009 microgram/L (P < 0.01). The assay curve is linear from 0.01 to 1.0 micrograms/L and has an overall assay time of about 4 h. Linear plots are obtained when the 1.0 micrograms/L standard is diluted with either matrix buffer or serum from men containing PSA < 0.01 microgram/L. Recovery of PSA (0.10 microgram/L) added to serum from men averaged 94%. Interassay CVs were 13%, 7%, and 4% at PSA concentrations of 0.04, 0.07, and 0.30 micrograms/L, respectively (n = 33). This assay should be useful in the detection of early recurrence of prostate cancer after radical prostatectomy.
authors.affiliation: Laboratory of Pathology of Seattle, Inc., WA 98104.
authors.forename: R J
authors.initials: RJ
authors.lastname: Liedtke
authors.forename: G
authors.initials: G
authors.lastname: Kroon
authors.forename: J D
authors.initials: JD
authors.lastname: Batjer
mesh_terms: D001322:Autoanalysis / Q000379:methods; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008832:Microchemistry; D017430:Prostate-Specific Antigen / Q000097:blood*; D011786:Quality Control; D012680:Sensitivity and Specificity
chemical_list: D017430:Prostate-Specific Antigen