From the Guidelines
A normal gallbladder ejection fraction is defined as ≥38%. This definition is based on the recommendations of an interdisciplinary panel that suggested the use of a standardized protocol for cholecystokinin-cholescintigraphy (CCK-CS) in adults, as described in a study published in the Clinical Gastroenterology and Hepatology journal in 2011 1.
Key Points to Consider
- The panel recommended a CCK-CS protocol involving infusion of 0.02 g/kg of sincalide over 60 minutes to determine the gallbladder ejection fraction.
- The primary indication for CCK-CS is in the diagnosis of functional gallbladder disease in well-selected patients.
- A gallbladder ejection fraction below the normal threshold may indicate gallbladder dysfunction, such as chronic cholecystitis or biliary dyskinesia.
Clinical Application
The measurement of gallbladder ejection fraction is crucial in clinical practice, particularly for patients presenting with biliary-type symptoms without evidence of gallstones on ultrasound.
- It helps clinicians assess gallbladder function and determine if symptoms are related to poor gallbladder function.
- This information is valuable when considering cholecystectomy for patients with suspected functional gallbladder disorders.
Evidence-Based Recommendation
The normal gallbladder ejection fraction of ≥38% should be used as a reference value in clinical practice, based on the most recent and highest quality evidence available 1.
From the Research
Normal Gallbladder Ejection Fraction
- A normal gallbladder ejection fraction (GBEF) is considered to be > or =35% with a 3-min infusion and > or =50% with a 10-min infusion of cholecystokinin-8 (CCK-8) 2.
- The mean GBEF value was reproducible between two sequential studies in the control group, with values of 66.0% +/- 20.5% and 73.9% +/- 17.7% 2.
- A study of 40 normal volunteers found that the maximum mean gallbladder ejection fraction occurred 15 minutes after CCK infusion and was 74.5% +/- 1.9% (mean +/- SEM), with a normal GBEF defined as greater than 40% (mean -3SD) 3.
Factors Affecting Gallbladder Ejection Fraction
- Opioid intake before the study can affect GBEF values, and exclusion of opioid intake is critical before attributing a low GBEF value to an irreversible GB motor dysfunction 2.
- CCK-induced cystic duct spasm is the etiology for low GBEF in both chronic acalculous cholecystitis (CAC) and chronic calculous cholecystitis (CCC) 2.
- The severity of GBEF reduction in CAC increases with time, with a mean reduction of 7.2% +/- 8.1% within 12 months, 16.1% +/- 14.9% in 13-47 months, and 23.5% +/- 21.3% in 48-168 months 2.
Clinical Implications
- A low GBEF value is associated with biliary dyskinesia, a functional gallbladder disorder characterized by altered gallbladder motility 4, 5.
- Cholecystectomy can alleviate symptoms in patients with biliary dyskinesia and a low GBEF value, with symptom resolution reported in 84% of patients in one study 5.
- However, the diagnostic value of cholescintigraphy in patients with acalculous right upper quadrant pain is low, and a low GBEF does not predict clinical outcome or histologic features of chronic cholecystitis 6.