CHICAGO (CBS) — Police Supt. Eddie Johnson was released from the hospital Saturday afternoon, three days after he received a kidney transplant from his son, Daniel.

Johnson received his new kidney on Wednesday at Rush University Medical Center. He has been suffering from a rare kidney disease for more than 30 years, but did not need a transplant until this year, when his doctors informed him his kidneys were functioning at only 10 percent capacity.

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The superintendent was released from the hospital around 4:30 p.m. Saturday.

“According to Mr. Johnson’s transplant team, his kidney function is excellent. He is in good condition and making great progress,” Rush spokeswoman Deb Song said in an email Saturday afternoon.

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Johnson’s doctors have said he will need to spend 3 to 6 weeks recovering at home, doing normal activities, but no heavy lifting, before he returns to work.

First Deputy Supt. Kevin Navarro has been running the department during Johnson’s treatment, but the two have been in regular contact.

The city’s top cop revealed he suffers from a rare kidney disease earlier this year, after falling ill at a press conference in January.

After the family learned his kidneys were functioning at only 10 percent capacity earlier this year, his 25-year-old son, Daniel, offered to donate a kidney to his dad.

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Daniel was released from the hospital earlier.