Interim home minister Shaukat Javed told ARY News that doctors gave the former premier a check-up and decided to shift him to the hospital after his blood tests showed clotting.
He said doctors from the Pims had conducted echocardiography (Echo), electrocardiography (ECG), and other tests and recommended he be shifted to the hospital in light of his medical reports.
The minister said Sharif, who takes medication for heart ailment, diabetes and cholesterol, will be kept at the hospital as long as doctors want him to stay there.
Sources said preparations are underway to shift him to the hospital as the jail administration and police have been put on an alert.
The former premier will be moved to the hospital any time soon after a nod of approval from the federal government.
Earlier, a medical board of the Pims had examined his health and declared his medical reports satisfactory.
The medical board, comprising doctors from the Pims, conducted his echocardiography, ultrasound, and echo tests. His blood pressure and sugar level were also tested.
The former premier was advised to continue taking medicines related to heart ailment and drink as much water as possible.
In the preliminary report compiled after the first checkup, the board decided that Nawaz should be given medical treatment within the confines of Adiala Jail.