Assessment of RNA amplification by multiplex RT-PCR and IgM detection by indirect and capture ELISAs for the diagnosis of measles and rubella

The aim of the study was to compare RNA amplification using multiplex RT-PCR and IgM detection by means of indirect and capture ELISAs for the diagnosis of measles and rubella. A total of 229 cases of maculopapular rash with serum and throat swab samples were included. Specific serological IgM to measles and rubella was determined by Enzygnost (R) (Siemens) and PlateliaTM (Bio-Rad). Both viruses were researched using multiplex RT-PCR performed on throat samples. Criteria for inclusion of measles or rubella cases were a positive RT-PCR result for one virus and negative for the other; and/or a positive IgM result for one virus by both ELISAs and negative RT-PCR for the other virus. A total of 74 cases were classified as measles and 54 as rubella. In measles, sensitivity and specificity were 93.2% and 100% for RT-PCR, 97.3% and 98.1% for Enzygnost (R), and 90.5% and 95.5% for Platelia (TM). For rubella, these values were 42.6% and 100% for RT-PCR, 100% and 97.1% for Enzygnost (R), and 94.4% and 98.3% for Platelia (TM). Enzygnost (R) and PlateliaTM are useful techniques for detecting IgM against measles and rubella. RNA amplification by RT-PCR was both sensitive and specific for the diagnosis of measles; however, for rubella, the sensitivity of this technique must be improved.