Staff at the National Virus Reference Laboratory are "frustrated" that they are working at a third of their capacity due to the lack of Covid-19 testing reagents, the substance or mixture used in chemical analysis.

Speaking on RTÉ's Today with Seán O'Rourke, NVRL manager Deirdre Burke said this is "taking a toll on staff" because she said everyone "is enthusiastic, proud, and are going the extra distance to get the results out".

She said there is an "air of deflation" within the lab that it is not running to its full capacity.

"We are down to about a third of what our original capacity was," she said.

"But it is only fair to say that everybody has been working around the clock to access reagents and what is more frustrating is that we can't do more and I think that is what the staff in the lab are trying to come to terms with. 

"There is such buy-in, such enthusiasm to get the results out. We were very proud about what we did. It is frustrating, and I think that is what is taking more of a toll on the staff here."

More reagents are expected to arrive imminently, Ms Burke said. 

She said that she understands that the HSE are working 24/7 to source them, but when they arrive "we can't just start using them straight away. We have to ensure that they are fit for use".

The NVRL is receiving calls from the public, she said, "Which are above and beyond" the number it would normally receive. 

People are "very anxious, they want to know when they can go back to work, or if they can come out of isolation". 

She said many people are asking if they can attend funerals.

Ms Burke explained staff are not able to give results over the phone and the NVRL will continue to liaise with GPs, ICUs and public health authorities.

Latest coronavirus stories

UCD has provided volunteers to "help ease telephone traffic" to the NVRL, Ms Burke said.

The intention is for all tests to be carried out on the island of Ireland, she said, but "a lot" of the samples have been sent to a lab in Germany, which was sourced by the HSE.

Ms Burke said swabs have a shelf life of a number of months.

In relation to the possibility of getting a false negative in a test for Covid-19, Ms Burke said "no test is 100 percent accurate". 

She said the virus may have moved "down to the lungs, and is no longer in the nose when the swab is collected", but she understands that the false negative rate is "very low".

On the issue of personal protective equipment (PPE) Ms Burke said staff at the NVRL are "used to dealing with nasty samples" and are wearing double gloves, PPE, visors and all samples are kept in safety cabinets, which provide "another layer of protection".