What laboratory tests are useful in confirming a diagnosis of measles in a clinical setting?

In a clinical setting, the confirmation of measles diagnosis primarily relies on laboratory detection of measles-specific IgM antibodies and/or measles RNA. The standard approach involves serological testing for measles IgM antibodies, which indicates recent infection, and can be performed using enzyme-linked immunosorbent assay (ELISA) techniques. Additionally, molecular methods such as reverse transcription polymerase chain reaction (RT-PCR) to detect measles RNA from clinical specimens (e.g., throat swabs, urine, or blood) provide direct evidence of infection and are useful for confirmation, especially in the early stages of disease or in vaccinated individuals where serology may be less definitive ¹.

Rapid diagnostic tests (RDTs) for measles IgM have been developed and show promise in improving case detection and targeting vaccination efforts, offering quicker results compared to traditional laboratory assays. These RDTs have been validated and are increasingly used in surveillance and outbreak settings, complementing standard serological and molecular tests (Brown et al., 2020; Rachlin et al., 2024).

It is important to collect appropriate specimens early in the course of illness to maximize diagnostic yield. The local Health Protection Team (HPT) should be notified immediately upon suspicion of measles to coordinate confirmatory testing and public health measures ¹.