15 minutes. Lie on the proper table, prep the skin, insert needle...Sometimes under ultrasound guidance, remove needle, may need more than one specimen.
Pretty quick. Most of the time for the actual procedure is spent positioning the patient and ascertaining the exact location and approach needed to acquire tissue from the liver, avoiding other organs in the area. The results of a liver biopsy will often be available in 2 days, but additional studies may delay the case several additional days.