Jaitley, 65, is undergoing diagnostic tests and doctors have so far indicated that it was a kidney-related ailment, they said.
The minister, however, has not yet been hospitalised but has been advised to avoid going out in public for fear of infection.
He has not been attending office since Monday and even skipped taking oath after being re-elected as Rajya Sabha MP from Uttar Pradesh. 53 out of the 58 newly-elected or re-elected members took oath of office during the last two days. Jaitley was one of the five members who hasn't taken oath.
Sources said Jaitley's present condition may be a fallout of the bariatric surgery he had undergone soon after the BJP government came to power at the Centre in 2014.
He underwent the surgery to treat weight gain that he suffered because of a long-standing diabetic condition.
That surgery was first performed at Max Hospital, but he then had to be shifted to AIIMS because of complications.
Sources said doctors from AIIMS are attending to Jaitley at his residence now. A final call is yet to be taken on whether a kidney transplant is required or not, they said.
Depending on doctors advice, he may be admitted to the Cardio-Neuro Tower at the All India Institute of Medical Sciences (AIIMS) here. The centre is housed in a separate building and is equipped with state-of-the-art equipment.
Though he has not been attending office since Monday, he is clearing files from his residence, they said.
The minister, who suffers from chronic diabetes, had heart surgery several years ago. He is a key member of the Prime Minister Narendra Modi's cabinet and presented his fifth and the present NDA government's final full budget on February 1.
The Budget was last month approved by the Lok Sabha without a discussion and it is not listed to be taken up in Rajya Sabha before the current session of Parliament ends tomorrow, thereby not requiring his presence for a reply.
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