Measles Oral Swab as Field-Based Screening Test in Children

BACKGROUND: Indonesia suffered from measles outbreak for many times, especially in the last five years. Most patients were children. WHO used measles specific Ig M from the blood as a gold standard but this test is invasive. Anti measles Ig M oral swab has been used as an alternative however there has not been any study about this method in Indonesia. The objective of this study was to validate anti measles Ig M oral swab for the diagnosis of measles in children. METHODS: This study was performed in Dr. Soetomo Hospital in Surabaya for three months period. Children with fever and rash suspected having measles according to WHO criteria were used as samples. Inclusion criteria included age 6 month until 15 year-old, with maculopapular rash, fever for at least three days, and at least one of cough, coryza, and conjunctivitis. Immunocompromized children and those with history of fever and rash or measles vaccination in the last 8–12 weeks were excluded. A blood specimen for serum anti measles Ig M and oral swab using transudate in gingivo-cervicular sulcus were taken at the same time. Method for oral swab specimen was microimmune(EIA) captured antibody assay for measles IgM. Measles specific IgM antibodies from blood specimen were measured by Enzygnost anti measles IgM. Mc Nemar test and kappa were used to analyze the results with P < 0.05. RESULTS: There were fifty-six children in the study. The age range was 6 – 72 months. Boys outnumbered girls with ratio 1.6:1. Most patients came on day third-sixth of illness. As much as 75.7% of the children were not immunized. Antimeasles Ig M were truly positive by both methods in fifty sampes. Detection of Ig M antibodies were similar either by using serum or oral swab (Mc Nemar, P = 1,00). The best ROC curve to detect anti measles IgM by oral swab was shown at the value of 0.2 (sensitivity 98%, specificity 60%, Kappa 0.638 with P < 0.0001, PPV 96%, and NPV 75%) For the value of 0.5 we had sensitivity 90%, specificity 80%, PPV 98%, NPV 44%, and Kappa 0.516 with P < 0.001. CONCLUSION: Anti measles IgM oral swab is highly sensitive and can be used as a field-based alternative screening method to diagnose measles infection. DISCLOSURES: All authors: No reported disclosures.