Hector,
believe me doctors do not do anything. They did a blood test and an ultrasound. They look at results and if they are normal, just say yes it is IBS.
Every 15 minutes they take a patient and how can they think in detail.
Best to ask your doctor as they are the only one who knows the status of your both conditions.
By the way an ultrasound is not used to measure progression of liver disease. A liver biopsy or Transient Elastography test such as Fibroscan is used for that..
Good luck.
Hector