E-commerce giant Rakuten Inc. said Monday it has started selling coronavirus testing kits to companies in Tokyo and four surrounding prefectures.

The self-assessment kit developed by genetic analysis firm Genesis Healthcare Co. is designed for people who suspect they have the pneumonia-causing disease but are asymptomatic.

The kit's polymerase chain reaction test will determine whether a nose swab sample contains the RNA sequences specific to COVID-19, the respiratory disease caused by the virus. Those who test positive still need to consult a doctor for confirmation.

Users place their samples in the leak-proof container provided, and deposit this at one of the specified locations for collection by Tokyo-based Genesis Healthcare, which is to send back the results within three days, excluding weekends and holidays.

Each one-person kit costs ¥14,900 including tax, and the minimum order is 100 kits. They are on sale to firms in Kanagawa, Chiba, Saitama and Ibaraki prefectures as well as Tokyo, and Rakuten plans to offer them in other parts of Japan starting in May.

Rakuten has a stake in Genesis Healthcare but has not disclosed how big of a stake.

Experts have warned that Japan, which has focused on tracking group infection, has been conducting significantly less testing than other countries.

The government is expanding testing capacity, but local health care centers face shortages of personnel and other resources to carry out tests. Meanwhile, some hospitals are turning away people suspected of carrying the virus due to a lack of capacity to treat them, and to prevent transmission to inpatients.