From the Guidelines
A normal gallbladder ejection fraction is defined as ≥38%. This measurement represents the percentage of bile that the gallbladder expels during contraction after being stimulated, usually by a fatty meal or cholecystokinin (CCK) during a hepatobiliary iminodiacetic acid (HIDA) scan 1. The ejection fraction is calculated by comparing the amount of radiotracer in the gallbladder before and after stimulation.
Some key points to consider when interpreting gallbladder ejection fraction results include:
- Values below 38% are generally considered abnormal and may indicate gallbladder dysfunction or chronic cholecystitis 1.
- The test helps clinicians determine if the gallbladder is functioning properly, as poor contractility can cause symptoms even without gallstones.
- Some centers may use slightly different reference ranges, so it's always best to refer to the specific laboratory's normal values when interpreting results 1.
In clinical practice, a normal gallbladder ejection fraction is crucial in evaluating patients with right upper quadrant pain who have normal ultrasound findings but suspected gallbladder disease. The recommended normal value of ≥38% is based on a standardized protocol involving infusion of 0.02 g/kg of sincalide over 60 minutes 1. This protocol provides a reliable and consistent method for assessing gallbladder contraction and calculating the ejection fraction.
From the Research
Normal Gallbladder Ejection Fraction
The normal gallbladder (GB) ejection fraction is a topic of interest in the medical field, particularly in the diagnosis and treatment of gallbladder diseases.
- A study published in 2003 2 found that a gallbladder ejection fraction of less than 35% was considered abnormal.
- Another study published in 2004 3 defined a normal gallbladder ejection fraction as > or =35% with a 3-min infusion and > or =50% with a 10-min infusion of cholecystokinin-8 (CCK-8).
- A 2007 study 4 determined that the lower limit of normal gallbladder ejection fraction values was 27.46% at 30 min and 61.44% at 60 min using a standard fatty meal.
- Additionally, a 2017 case report 5 suggested that a normal unexpected gallbladder ejection fraction is sufficient evidence for normal gallbladder function and may obviate the need for sincalide stimulation.
Factors Affecting Gallbladder Ejection Fraction
Several factors can affect the gallbladder ejection fraction, including:
- Cholecystokinin stimulation: used to calculate the gallbladder ejection fraction during cholescintigraphy 2, 3.
- Fatty meal ingestion: can stimulate gallbladder contraction and affect the ejection fraction 4.
- Opioid intake: can affect the gallbladder ejection fraction and should be excluded before attributing a low value to an irreversible gallbladder motor dysfunction 3.
Clinical Implications
The gallbladder ejection fraction has clinical implications in the diagnosis and treatment of gallbladder diseases, including: