Lumipulse: Novel antigen test for quantifying SARS-CoV-2 in saliva

It is simple, rapid, and more conducive for mass-screening.

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Real-time reverse transcription-polymerase chain reaction (real-time RT–PCR) is one of the most accurate laboratory methods for detecting, tracking, and studying the COVID-19 coronavirus. This method requires trained personnel at every step, from collecting nasal swab samples to interpreting the results. Also, the process takes 2-3 days.

As the virus can be transmitted by an infected person before symptoms develop and is even transmitted by asymptomatic individuals, the ability to screen a large number of people quickly is vital to controlling and preventing the spread of the pandemic. Faster methods to detect the SARS-CoV-2 antigens have been developed, but they are not as sensitive as the RT-PCR test.

In 2020, Fujirebio came up with a novel antigen-based kit called Lumipulse® SARS-CoV-2 Ag kit (Lumipulse), which measures the viral antigen in biological samples within 35 minutes.

Now, scientists from the Hokkaido University used the Lumipulse® SARS-CoV-2 Ag kit to detect SARS-CoV-2 in saliva samples. They also accessed the efficiency and accuracy of the test kit as compared to RT-PCR.

They found that the antigen detection kit, used to perform chemiluminescent enzyme immunoassay (CLEIA), can rapidly detect SARS-CoV-2 with good accuracy. The fascinating features of this novel test are: simple, rapid, and more conducive for mass-screening.

The test was performed on 2056 individuals from three cohorts: patients with clinically confirmed COVID-19, individuals who had contacted patients with COVID-19, and individuals tested on arrival at Tokyo and Kansai International Airports. Scientists collected saliva samples from all individuals and performed RT-PCR tests as well as CLEIA using Lumipulse.

By comparing the results, scientists determined the usefulness of CLEIA. CELIA shows the test results within an hour.

Combined CLEIA and RT-PCR testing on saliva samples have already been implemented at Japanese airport quarantines. The authors recommend adopting it at a broader scale to rapidly screen for SARS-CoV-2.

Journal Reference:
  1. Isao Yokota, et al. A novel strategy for SARS-CoV-2 mass-screening using quantitative antigen testing of saliva: a diagnostic accuracy study. The Lancet Microbe. May 19, 2021. DOI: 10.1016/S2666-5247(21)00092-6