Surgeon drained 500ml of thick red fluid from abdoman yet said it was a seroma is that correct as the second time 140ml was dark brown in colour?

Seroma: Seroma after any surgery can occur. Stay with your surgeon and ask for the culture results and when the ultrasound will be done. Post operative seromas are frustrating, painful, occasionally become infected, usually resolve spontaneously or with office drainage. The seroma can take 2 to 8 weeks to resolve.

Hematoma: Sounds like a hematoma as it is usually red at first then brown as the blood hemolyzes. Seroma fluid is usually clear. Treatment for both is usually the same.