UMEM Educational Pearls

Category: Ultrasound

Title: FAST exam Pitfalls

Keywords: POCUS; FAST exam; Trauma (PubMed Search)

Posted: 6/17/2024 by Alexis Salerno, MD
Click here to contact Alexis Salerno, MD

Although the FAST exam can be helpful in expediting care of patients with intraabdominal injuries, there are a few pitfalls. 


1. The FAST exam has a wide sensitivity which depends on sonographer skill and the patient's body habitus. It is best used as a “Rule In NOT Rule Out” exam. 

2. The FAST exam is not good for identifying bowel injury or retroperitoneal bleeding and may not be able to pick up low volume hemoperitoneum. 

3. The FAST exam is not able to identify the type of fluid e.g. ascites vs blood. 

Some Tips for Performing the FAST exam:

1.Go slow, fan through the view completely. In the RUQ view make sure you are evaluating the liver tip.

2. Place the patient in slight Trendelenburg. 

3. If you have clinical concern for injury, don't stop at a negative FAST.


Savatmongkorngul S, Wongwaisayawan S, Kaewlai R. Focused assessment with sonography for trauma: current perspectives. Open Access Emerg Med. 2017 Jul 26;9:57-62. doi: 10.2147/OAEM.S120145.