Mitra, who was asked by scribes whether TMC factionalism was responsible for his defeat, replied "There was no factionalism but because of the collusion between the police and CPI-M I lost. I have sent a report to Mamata Banerjee.
"I could not campaign, yet I have got so many votes. I express my gratitude to the people," he told reporters at SSKM hospital when he came out for a test.
Mitra, a Saradha chit fund scam accused was admitted to hospital due to chest pain and difficulty in breathing last month.
He is in jail for more than a year as a prime accused in the case and fought the assembly poll from behind the bars.