The potential treatment, known as convalescent plasma, will help patients whose bodies are not producing sufficient antibodies to fight the virus.
The first donations have already been collected as scientists begin the fight-back against the pandemic, with transfusions starting in "the coming weeks".
And among those who are helping to tackle the virus is Darren Buttrick, from Coven, who was admitted to New Cross Hospital on March 20 after suffering from coronavirus.
He has now fully recovered from Covid-19 and is determined to help others, having already donated his plasma at Birmingham's NHS Blood Donation centre on April 25.
The 48-year-old joins the likes of Dr Zahid Safraz, from West Bromwich, who donated his plasma to help tackle the virus.
"I thought it was a hoax call at first, but when they explained I said 'most definitely' – they're doing trials on plasma," Mr Buttrick said.
"They take the blood out, extract the plasma – which is yellow – and it goes into a bag and sent off.
"My antibodies will help people fight coronavirus and I knew I wanted to help immediately.
"I wanted to help, definitely, I was delighted to because I know how poorly I was and how the NHS saved my life."
Mr Buttrick, who works for O2 as head of strategic clients, started to develop symptoms after returning from London on a business trip.
Days later he began to experience symptoms of breathlessness and a high temperature, with paramedics initially admitting him to hospital on March 14.
The father-of-three was discharged the following day but was told two days later he had tested positive for the virus.
He followed Government guidelines to stay at home as his symptoms grew worse and was then again admitted to New Cross Hospital on March 20.
Rapidly deteriorating, he was put on a ventilator and told he had a 50/50 chance of surviving.
"I went to New Cross Hospital and they said I was very very poorly – and they said I might not make it," he said.
"They said they would take me to the theatre and put me on a ventilator. I said I didn't want that, but they stressed I needed to if I wanted to survive.
"They told me to ring my loves ones and said 'we will do everything possible we can to save you, but this is 50/50'."
Mr Buttrick was given 15 minutes to tell his family the unfortunate news that he might not make it, which he said was one of the "worst" things he ever had to do.
He had to call his parents and other members of his family including wife Angela, 15-year-old twin daughters Freya and Maia and 13-year-old daughter Esme.
"I did my calls and hearing your parents crying on the phone, it's one of the worst things I've had to do in my life.
"I know I'm very very lucky to get through it all.
"I remember telling them 'don't let me die' and they were very good. You have no idea if you will wake up or not – so I know I'm very lucky.
"They took me to one of the theatres there and told me I would get through it. I remember counting to three and I was gone on a ventilator – I was in their hands."
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Five days later and Mr Buttrick was recovering, but his body didn't react very well to coming off the ventilator – meaning he was placed on another ventilator.
"When I woke up I was just on an oxygen mask and there was two nurses – one at the end of the bed and another holding my hand," he added.
"I said 'thank you' and she asked whether I wanted her to FaceTime my wife. It was a really lovely touch and it meant so much to me.
"Apart from the two nurses – Joanne Roberts and Dawn Sothey – you had a doctor at the end of your bed 24/7.
"It was a frightening experience but the NHS, all the staff were just amazing and so positive."
He was later transferred to a high dependency unit for two further days, before being discharged late on March 26.
Almost a month later he was contacted by Public Health England to take part in a clinical trial to fight-back against the virus.
He has been praised by his family and friends for his efforts, with the chief executive of O2 writing to him constantly to keep a check on his health.
Health and Social Care Secretary Matt Hancock said hundreds had been chosen for national trials which could mark a "major milestone" in the fight.
Mr Hancock said: "This global pandemic is the biggest public health emergency this generation has faced and we are doing absolutely everything we can to beat it.
"The UK has world-leading life sciences and research sectors and I have every hope this treatment will be a major milestone in our fight against this disease.
"Hundreds of people are participating in national trials already for potential treatments and the scaling up of convalescent plasma collection means thousands could potentially benefit from it in the future."