A doctor said the treatment has been started after the diagnosis was confirmed, reports The Express Tribune.
He added that the ailment was treatable in Pakistan and intravenous treatment has commenced.
"He does not have aplastic anaemia and his haemoglobin and WBC count (white blood cells) are normal. Platelets are low though," said the docto.
He added that Sharif's bonemarrow was also functioning normally and is making blood as it should in addition to a normal level of reticulocytes.
Earlier on Thursday, Pakistan Muslim League-Nawaz President Shehbaz Sharif filed a petition in the Islamabad High Court (IHC) seeking his brother's bail on medical grounds.
The PML-N supremo was taken to Services Hospital from the National Accountability Bureau's (NAB) Lahore office late Monday night after a decline in his platelet count.
Nawaz Sharif received transfusions of mega units of platelets at the hospital the next day. The government officials, as well as his party leaders, had told the media that he was in a stable condition after he underwent the treatment.
However, his condition deteriorated on Wednesday evening after his platelets count again fell sharply to a life-threatening level of 7,000.
Punjab Health Minister Yasmin Rashid also met the former premier at the hospital and claimed in a news conference that "Nawaz was satisfied with the treatment".
The former premier had been shifted from the Kot Lakhpat jail (where he is serving seven-year imprisonment in Al-Azizia case) to NAB's Lahore building following his arrest in the Chaudhry Sugar Mills case. The bureau has obtained his physical remand till Friday.
( With inputs from IANS )