Margrethe, 82, who has been on the throne for 50 years, canceled her official duties after the Tuesday night test, the royal household said in a statement.
The queen was among the dignitaries who attended Queen Elizabeth II's funeral Monday at Westminster Abbey in London.
Queen Margrethe II's oldest son -- heir to the throne Crown Prince Frederik, and his wife, Crown Princess Mary, would would take the queen's place hosting a dinner with Danish government officials and members of parliament, the palace said.
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Earlier in February, the Queen was tested positive for the virus, the palace said, adding she had received three doses of a COVID-19 vaccine.
Following the 8 September death of Queen Elizabeth II, who ruled fro 70 years, Margrethe's half-century reign makes her Europe’s longest-serving monarch.
Margrethe had asked her court to adjust the 10-11 September program for her own 50-year anniversary commemorations, as a respect for the late British monarch. She also canceled at short notice was appearing on the Amalienborg Palace balcony to greet well-wishers and a ride in a horse-drawn carriage through Copenhagen.
The Danish Queen was proclaimed queen on 15 January, 1972, a day after her father, King Frederik IX, died following a short illness.
With AP inputs.
