After Panwar's 'A' sample was found positive, the Indian Weightlifting Federation (IWF) suspended her provisionally.
The National Anti-Doping Agency (NADA) conducted dope tests on all the national campers on March 25 in Patiala.
"Forty two weightlifters were tested and only Sushila's sample was found to be positive," IWF Secretary Sahdev Yadav told PTI.
Panwar, who hails from Uttar Pradesh, came to the limelight when she bagged a gold medal in the +75kg category at the 12th South Asian Games in Guwahati last year.
Panwar had clinched the lone gold medal in weightlifting with a total lift of 198kg ahead of Ishani Annushka of Sri Lanka and Tara Devi Pun of Nepal.
Photograph: Michael Regan/Getty Images