Infectious Diseases in Obstetrics and Gynecology I: 188-192 (I 994) (C) 1994 Wiley-Liss, Inc. Comparison of Five Methods for the Determination of Rubella Immunity Robert L. Sautter, Arthur E. Crist, Jr., Lynn M. Johnson, and William D. LeBar Department of Pathology, Harrisburg Hospital (R.L.S.), Departments of Pathology (A.E.C.) and Laboratories (L.M.J.), Polyclinic Medical Center, Harrisburg, PA, and Citation Clinical Laboratories, Providence Hospital (W.D.L.), Microbiology Laboratory, Southfield, MI ABSTRACT Objective: The purpose of this study was to compare the accuracy of commonly used methods for the detection of rubella immunity, especially the fully automated IMx assay. Methods: A total of 190 sera (101 immune and 89 non-immune) submitted to Harrisburg Hospital or Polyclinic Medical Center for the determination of rubella immunity were tested by enzyme immunoassay (IMx and Rubazyme, Abbott Diagnostic Laboratories, North Chicago, IL), indirect immunofluorescence (FIAX, Whittaker Bioproducts, Walkersville, MD), and latex agglutination (Rubascan, Becton Dickinson Microbiology Systems, Cockeysville, MD, and Rubalex, Wellcome Diagnostics, Research Triangle Park, NC). Specimens were frozen at -30C until the study was initiated. Each of the assays was performed according to the manufacturers’ specifications. Sensitiv- ity, specificity, accuracy, and positive and negative predictive values for each assay were calculated using a consensus result of the 5 methods tested. Results: The sensitivity, specificity, and accuracy, respectively, of the test systems were as fol- lows: IMx, 96%, 97%, and 96%; Rubazyme, 100%, 99%, and 99%; Rubascan, 100%, 98%, and 99%; Rubalex, 99%, 97%, and 98%; and FIAX 90%, 100%, and 95%. False negative reactions were seen with the FIAX system. Conclusions: The IMx system, a new "walk away" system from Abbott Diagnostic Laboratories and the Rubazyme systems performed well; however the latex agglutination tests proved to be the most rapid and convenient methods for screening sera for the presence of rubella immunity. (C) 1994 Wiley-Liss, Inc. KEY WORDS IMx, enzyme immunoassay, latex agglutination, fluorescent immunoassay, comparison of viral immunological methods ublic health measures to reduce the transmission of rubella are dependent upon the vaccination of children > 12 months of age, school-age children not previously immunized, and susceptible adults. The occurrence of rubella during pregnancy can result in severe congenital abnormalities of the new- born. Current guidelines suggest that women of childbearing age should be evaluated for immune status to rubella. If they are negative, they should be monitored throughout the pregnancy for sero- conversion. If these women remain negative fol- lowing delivery, then they should be vaccinated postpartum. In addition, health care personnel are monitored at most pre-employment physicals; if they are found to be non-immune, vaccination is recommended. The rubella antibody test is one of the most frequently ordered tests in the serology laboratory. Address correspondence/reprint requests to Dr. Robert L. Sautter, Director, Clinical Microbiology, Department of Pathol- ogy, Harrisburg Hospital, South Front Street, Harrisburg, PA 17101-2099. Basic Science Article Received November 29, 1993 Accepted January 28, 1994