Additional Listing to Correct Discrepancy

3 June 2021

Immunodiagnostic Systems Holdings plc

Additional Listing to Correct Historical Discrepancy

Immunodiagnostic Systems Holdings plc ("IDS" or the "Company") (LSE: IDH) today announces that an application has been made to the London Stock Exchange for the admission of 102,674 ordinary shares of 10p each ('Ordinary Shares') in IDS in order to correct a historical discrepancy between its issued share capital and the share capital recorded as having been admitted to trading on AIM.

On 10 May 2010, IDS announced the issue and allotment of 2,674 Ordinary Shares to satisfy an exercise of options and on 29 June 2011 IDS announced the issue and allotment of 100,000 Ordinary Shares to satisfy an exercise of options. In both cases a listing application was not submitted due to an administrative oversight and therefore 102,674 Ordinary Shares were not admitted to trading on AIM at that time. It is expected that the 102,674 Ordinary Shares will be admitted to trading on 8 June 2021.

No new Ordinary Shares have been issued or allotted and IDS confirms that its issued share capital remains unchanged at 28,784,097 Ordinary Shares as at 2 June 2021 (excluding 627,078 IDS Shares held in treasury).

For further information please contact:

Immunodiagnostic Systems Holdings plc Tel : +44 (0)191 5190660

Paul Martin, Group Finance Director

Peel Hunt LLP Tel : +44 (0)207 418 8900

James Steel

Victoria Erskine