FAST fails (Things that will mess up your FAST)

(This post first published on on November 4, 2015)

The FAST exam is an examination that is ubiquitous in emergency medicine, and the more I do them, the more I realize that their correct interpretation takes some training.  If you don’t know how to properly do a FAST exam, START HERE. The following is a list of things that will cause you to have a false-positive or false-negative FAST:

Right upper quadrant:

  • Perinephric fat
  • Gallbladder
  • Not looking at the inferior pole of the kidney/caudal tip of the liver interface


  • You’re too high (probe should sit right above the pubic symphysis)
  • Iliac vessels
  • Probe not oriented sagitally

Left upper quadrant

  • Perinephric fat
  • Stomach
  • Not looking superior to the spleen

Here’s a video summary: