t's not a ****** competition Iains

There is a worldwide shortage of the reagent required for testing. The Irish deputy chief medical officer has just mentioned this as being a problem. It is also a problem in the US. Ramping up testing has put this chemical in short supply.
HSE apologises to those waiting for test results, Taoiseach ...
RTE.ie-4 hours ago
... testing for Covid-19 due to the global shortage of testing kits, reagents and ... challenges in terms of securing supplies of reagent for testing.

Robert Peston: Is Michael Gove right that there is a shortage of ...
ITV News-31 Mar 2020
... in increasing the number of Covid-19 tests is due to a shortage of the ... capacity to increase testing overall is supply of the specific reagents,
Limited reagent gives rise to limited testing