title: The interpretation of ELISA results by means of the standard deviation ratio.
abstract: An improved sensitivity to low levels of hepatitis B surface antigen (HBsAg) was demonstrated when ELISA results were interpreted by a statistical method. The absorbance of each test well was compared with the mean absorbance of all low-colour test samples. Those wells with an absorbance of more than two standard deviations above the mean were referred for confirmatory tests. Samples containing 1.0 ng/ml of HBsAg were reliably detected by a rapid assay technique (1.5 h). Predictive value analysis showed greater sensitivity than was possible from a direct comparison of test samples with controls.
authors.affiliation: Natal Blood Transfusion Service, Pinetown, Republic of South Africa.
authors.forename: R M
authors.initials: RM
authors.lastname: Parkinson
authors.forename: J D
authors.initials: JD
authors.lastname: Conradie
authors.forename: L V
authors.initials: LV
authors.lastname: Milner
authors.forename: T
authors.initials: T
authors.lastname: Marimuthu
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards*; D005188:False Negative Reactions; D005189:False Positive Reactions; D006514:Hepatitis B Surface Antigens / Q000032:analysis*; D006801:Humans; D011237:Predictive Value of Tests; D012015:Reference Standards; D012016:Reference Values
chemical_list: D006514:Hepatitis B Surface Antigens