The thieves took the vital equipment from a lorry parked in Harlow Business Park in Essex, in the early hours of yesterday morning.
However Essex Police managed to track down and recover the NHS goods before they were sold on the black market.
Three men have now been arrested and remain in custody on suspicion of theft.
Essex Police swooped on thieves who stole the lateral flow coronavirus tests from a lorry parked in Harlow Business Park
Chief Superintendent Stuart Hooper, who oversees local policing in west Essex, said: 'Our colleagues in the NHS, and dedicated volunteers across the country, are working tirelessly to stop the spread of coronavirus and save lives.
'I'm thrilled that we were able to recover the lateral flow tests so that those in need are able to keep themselves and others safe at this difficult time.
'I'd like to remind the people of Essex that you can go and get yourself tested at sites across the county, and we'd encourage you to do so where possible.'
A 31-year-old man from Canvey Island, in Essex, a 27-year-old man from Newham, London, and a 37-year-old man, from Dagenham, all remain in custody on suspicion of theft.
The man from Dagenham has also been arrested on suspicion of drug driving.
It comes as NHS bosses today revealed Britain's coronavirus vaccine drive should drastically pick up pace from March 15 because supplies will 'increase substantially'.
The police confirmed the three men had been arrested and encouraged the people of Essex to get tested
Ministers promised March would be a 'bumper' month for the roll-out after the programme, which is crucial to Britain's hopes of seeing lockdown eased over the next few months, slowed down in February due to manufacturing issues.
Health chiefs have told local Covid vaccination teams to get prepared for extra supplies, hinting the UK may get almost 5million doses a week from next Thursday — double the amount it is currently receiving.
Vaccination sites across the country have also been told to ensure enough staff are ready to help from March 15.
Bosses have also revealed plans to clamp down on regional disparities in the roll-out after it was found that some parts of the country had already began dishing out jabs to healthy people in their twenties and thirties.