The suspects told women they had to provide blood samples to qualify for financial assistance from the Punjab government, police told BBC Urdu.
However, they extracted spinal fluid instead, and attempted to sell it on the black market, police added.
The gang is thought to have stolen spinal fluid from over 12 women, including a teenager.
The authorities became aware of the scheme after a man noticed that his 17-year-old daughter felt weak after the procedure.
"It appears the gang has been active in the Hafizabad area for some time," regional police officer Ashfaq Ahmed Khan told BBC Urdu's Shahzad Malik.
One member "went around posing as an employee of the District Headquarters Hospital, telling his victims they would need to provide blood samples in order to qualify for the Punjab government's dowry fund".
"But instead of taking them to the hospital to obtain their 'blood samples', he would take them to the house of a female member of the gang to perform the procedure," Mr Khan added.
