Measles is a highly contagious viral disease clinically characterized by fever, cough and rash. It’s expression in younger or undernourished children leads to more complications. Presence of IgM antibody at the onset of rashes and persistence of raised titres for 4 weeks signifies acute phase of the disease. A single positive IgM result should not be used as a sole determinant of current or recent infection due to false positivity. A repeat test after 2-4 weeks of infection is recommended to confirm acute infection. IgM titres become negative by about 4 months.