A woman with suspected Covid-19 died after testing negative three times for the virus, her family said.
Julie Taylor-Broadbent, from Hull, died in hospital on 8 May, four days before her 50th birthday.
Her family said they had “no confidence” in the swab test system and called for a public inquiry into the government’s handling of the pandemic.
The Department of Health and Social Care (DHSC) said its testing scheme was “reliable and effective”.
The 49-year-old had been admitted to hospital with a burst ulcer on 4 May, but her condition worsened and she was given oxygen therapy as she had trouble breathing, her family said.
The following day while in hospital she had her first coronavirus test, which came out negative. Because she was still presenting with potential virus symptoms she had two further tests in hospital on 6 and 7 May that each returned negative results.
Jayne Taylor-Broadbent, 54, said her wife’s death was “testament” that the swab tests were not working.
“Three tests and she’s not here. She tested negative three times,” she said.
The doctor explained that while she had been displaying Covid-19 symptoms her results were consistently showing as negative.
“I want honest answers. I want to know why Julie died. We’re getting no answers from the government really,” Mrs Taylor-Broadbent said.
The DHSC said “all swab tests” were assessed “as performing to the manufacturer’s specifications” prior to being deployed, but there was a “small possibility” of a false negative or a false positive result “like any diagnostic test”.
“Testing is reliable and effective, and NHS Test and Trace has already helped isolate more than 180,000 cases – with no significant rise in cases since the country started emerging from lockdown,” a spokesman said.
Julie’s daughter, Emma Smith, 26, said she found the response from the DHSC describing the tests as reliable and effective “really insulting actually”.
The widow said she was campaigning for an independent public inquiry to “put things right” and have measures in place “so if we do get hit by a second wave we’re in a lot better position”.
Ms Smith continued: “I would like them to see what they’ve done, see how much hurt they’ve caused and sort it out quite frankly.”
The DHSC added: “Every death from this virus is a tragedy, and our deepest sympathies go out to everyone who has lost loved ones.”