Government chiefs have faced mounting pressure over failings in the system, which has seen demand outstrip supply across the UK
Now figures have revealed a total of 3,297 people – out of 8,237 close contacts identified – have not been contacted, or told to self-isolate due to potentially having the virus, meaning only 60 per cent have been reached.
It comes amid rapidly rising case numbers across the country – with local virus restrictions being implemented in Wolverhampton, Sandwell and Birmingham.
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Data from the Department for Health and Social Care showed a total of 3,543 people who tested positive in the Black Country and Staffordshire were transferred to the NHS Test and Trace service between May 28 and September 9.
A total of 974 tested positive for coronavirus and were transferred in Sandwell, 535 in Wolverhampton, 344 in Dudley, 427 in Walsall and a further 1,263 in Staffordshire between the two dates.
A further 8,237 people, who are in close contact with the person within 48 hours before their symptoms started, were identified by people who gave the information to NHS chiefs.
The close contacts are referred to as being "non-complex" cases which means they can be dealt with through a call centre by the service or online.
Of the 8,237 identified by Test and Trace, a total of 3,297 have not been contacted – with 2,253 in the Black Country and 1,044 in Staffordshire.
In Sandwell, 1,043 people have not been reached out of 2,308 – with 55 per cent, the lowest in the Black Country, contacted.
In Wolverhampton, 543 have not been reached out of 1,234 people – with 56 per cent contacted. In Dudley, 259 out of 740 were not reached – with 65 per cent contacted, the highest in the Black Country.
Another 408 were not reached in Walsall out of 1,036 identified, with 61 per cent contacted. And in Staffordshire, another 1,044 were missed, out of 2,979 – with 65 per cent reached by chiefs.
Saffron Cordery, chief executive of NHS Providers, said this falls "well short" of SAGE's 80 per cent target.
She said: "Trust leaders are increasingly concerned with the current testing shortages impacting on NHS service recovery and winter preparations due to staff and their family members being unable to access a test.
"Additionally, with the number of positive Covid-19 cases increasing, but a reduction in the proportion being contact traced, we are looking at renewed pressure on the NHS."
Baroness Dido Harding, who heads up the NHS Test and Trace service, admitted last week that demand for tests was outstripping capacity but denied claims that the system was "failing".
She suggested around a quarter of those coming forward for a test did not have symptoms.
Under new rules, from September 28, people in England will legally have to self-isolate for 14 days if they test positive for coronavirus, or they are instructed to do by NHS Test and Trace.
Fines for non-compliance will start at £1,000, rising to £10,000 for repeat offenders, while people on benefits will be eligible for a one-off support payment of £500 if they face a loss of earnings as a result of having to quarantine.