The assistant, who works in a personal capacity for US President Donald Trump's daughter, has not been around her in several weeks, the CNN reported.
She has been teleworking for nearly two months and was tested out of caution, the report quoted a source as saying.
She was not symptomatic. Ivanka and her husband Jared Kushner both tested negative on Friday, the person familiar with the matter told the US news channel.
The development comes a day after President Trump confirmed that Vice President Mike Pence's press secretary Katie Miller had tested positive for the coronavirus.
"She's a wonderful young woman, Katie, she tested very good for a long period of time and then all of a sudden today she tested positive," Trump said during a meeting at the White House.
He said Miller had not come into contact with him but spent some time with Pence.
One of Trump's personal valets tested positive for the coronavirus on Thursday.
Following the news of the valet's illness, Trump said he would be tested for the coronavirus daily.
According to a senior official, contact tracing was performed inside the White House after Miller's test came positive.
The White House is now making sure staffers wear masks in the White House residence, and coronavirus tests and temperature checks are being boosted throughout the West Wing. The West Wing is also being sanitised on a more frequent basis, the official said.
Pence, who leads the White House coronavirus task force, recently went on a trip to the Mayo Clinic without wearing a face mask, despite being told about the clinic's policy saying they're required.
Trump also declined to wear a mask this week during portions of his tour of a mask-making facility in Arizona. MRJ AKJ
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