The woman approached the court of additional chief metropolitan magistrate Monday, her lawyer Gyan Singh said.
"The rape victim fears the blood samples may have been swapped in connivance with doctors. Nagar is an influential man. He had earlier refused to undergo the test even when police served three notices on him, but he suddenly gave his consent," the lawyer said.
A medical examination was conducted on Nagar by a team of doctors at SMS Hospital Saturday. The doctors took his blood and semen samples for a DNA test.
Gyan Singh said the woman has demanded that the medical examination be conducted again in the presence of a magistrate.
Nagar, who was minister of state for dairy and rural industries, was accused by the woman of raping her at his government bungalow here Sep 11. Nagar resigned Sep 20.
The Congress-led state government has recommended a Central Bureau of Investigation probe into the case.