[Practicability and reliability of a new rapid detection kit for rubella antibody]

We have investigated the practicability and reliability of a new rapid detection kit for rubella antibody by means of an immunochromatographic assay. This kit can measure 100 microliters of total blood or 50 microliters of serum or plasma in approximately 10 minutes. When a band appears in this kit, a sample is positive. The subjects of this investigation were 233 medical students or nursing students. Blood was also drawn from their fingertips of 71 of them. The blood was obtained with a lancet for measuring blood sugar. By an ELISA assay using IgG antibody for rubella, 188 samples (80.7%) were found to be positive, 1 sample (0.4%) was +/-, and 44 samples (18.9%) were negative. The positive IgG antibody titers deviated toward the lower levels since the median was lower than the mean. Therefore, the subjects were appropritate for evaluation of low titer samples. In comparison with the measurement of IgG antibody using the ELISA assay, the sensitivity and specificity levels of this new kit were 99.5% and 100%, respectively. The correlation index between the antibody titers and color concentration of the band was as weak as 0.5 (0.35-0.58 at 95% confident range). Seroconversion of the antibody in paired samples is necessary for diagnosis of rubella in this kit. However, if there is an uncertain past history of vaccination and/or rubella, this kit is useful for evaluating the need for vaccination in 10 minutes. It usually takes approximately one week to receive antibody results through a commercial laboratory.