Gallbladder Ejection Fraction: A Number Without Its Protocol

A gallbladder ejection fraction under 35% is read as a lazy gallbladder. But the number swings with how the test hormone is dripped in. In 93 patients it did not predict who got better after surgery. The classic gallbladder pain pattern did. Those patients were 22 times more likely to get relief.

A gallbladder ejection fraction under 35% with a clean ultrasound is how most operating rooms define a lazy gallbladder. It is the number that decides who loses an organ. It is also a product of the test method. For years I ordered it and treated its cutoff as a fact of nature.

Chapter 23 of The Angry Gut, Bile Is a Hormone, Not Soap, makes the case from body function. What follows is the case from measurement. What is that percentage made of? What does bile actually signal? And what terrain grew the stone in the first place?

Where does the gallbladder ejection fraction cutoff come from?

The normal range everyone quotes came from 60 healthy volunteers at four centers. The lower limit of normal landed at 38%, set at the 1% confidence bound. The scatter depended entirely on how the test hormone was dripped in. At best, the coefficient of variation (how much results scatter) was 19% with a 60-minute infusion. With the short infusion most places use, it was 52%. At 30 minutes, it was 35%.

So the test scatters more than the gap between a normal and an abnormal result. That study enrolled only volunteers. It was built to describe normal. It was never built to show that a low number predicts benefit from surgery.

What does predict benefit is the symptom pattern. Researchers followed 93 patients in a row with a proven slow gallbladder. The test number was the same in those who got better after surgery and those who did not: 19 plus or minus 9% against 16 plus or minus 7%. Patients with classic gallbladder pain were 22 times more likely to get relief, and 97% of them did. Among the patients with unusual pain, 9 of 32 got better with no operation at all. A cutoff with no method attached is a number wearing a lab coat. That is the same problem as a liver enzyme read without its context.

What does gallbladder sludge on an ultrasound mean?

The other word that gets an organ removed is sludge. Ultrasound found it in 1.7% of 17,021 patients. On repeat scans, most of it was gone. In 71.4% it cleared within about two months. Stones appeared in 8.9%, and acalculous cholecystitis (an inflamed gallbladder with no stones) in 7.1%.

Do not read that as permission to ignore it. Followed forward, 19.6% got stones or problems such as acute cholecystitis. That came from a small group of 56 people who grew sludge while being watched, over an average of 20.3 months. The stones that appeared caused no symptoms. One in five is not nothing. It argues for a watching plan with a date on it.

Bile is a hormone, and the signal is graded

Here is what the ejection fraction cannot see. Researchers exposed human small-bowel tissue to one bile acid at a time. They tracked a gut hormone called fibroblast growth factor 19. The half-maximal response came at 20 micromolar of chenodeoxycholic acid. The lower gut reaches that level after a fatty meal. The receptor is tuned to a dinner, not to a drug dose.

Then the ladder. Against chenodeoxycholate, cholate produced 81% of the response. Deoxycholate produced 40% and lithocholate 4%. Those last two are secondary bile acids. Your gut bacteria make them out of the primary ones. This is tissue grown in a dish. It measures gene signals, not blood sugar.

Here is what that means for terrain work. Your gut bacteria set the volume on a hormone your own gut makes, because the bacteria decide which bile acids exist to be read in the first place. Then the loop runs back the other way, since bile keeps the upper gut thinly populated and shapes who lives there. The bugs and the signal shape each other. That is the mechanism under a microbiome that drives symptoms elsewhere.

Why one blood draw cannot score this system

In a living person this system runs on a clock. Resting levels of that growth factor vary ten-fold between normal people. They fall when bile acids are bound up in the gut and rise when bile acids are fed. They peak 90 to 120 minutes after bile acids rise in the blood from a meal. Fasting wipes out the rhythm altogether.

There is no normal range waiting to be quoted here. After gallbladder surgery, bile acid production doubled. Yet blood bile acids, cholesterol and triglycerides did not budge. The tissue is a hormone source, and the routine panel cannot see it.

A number is only useful when its method, its timing and its reference group travel with it. That is the standard behind testing whether a body can heal rather than collecting results.

What a drug bought at that receptor, and what it cost

The obvious move was to hit the receptor with a drug. That experiment has run its course. In 20 patients on a lab-made drug that switches on the receptor, the growth factor rose from 95.0 to 234.4 ng/L. The liver’s bile acid production collapsed from 31.4 to 2.8 nmol/L. The bile in the gallbladder went dilute, 77.9 against 196.4 mmol/L on placebo. Its cholesterol saturation index rose to 2.8 from 1.8. That means more detergent and less power to hold cholesterol in solution.

In the large liver scarring trial, a blinded re-read found improvement in 22.4% on the higher dose against 9.6% on placebo. Disease resolution missed significance. Itch appeared in 51% of patients on the high dose against 19%. Accelerated approval came in May 2016. Withdrawal came in November 2025. So the system is real and reachable, and the leading drug aimed at it is off the market. Your own body aims a meal at that receptor every day. It comes in a pulse, with an off switch. A tablet has none of those. That is why the interventions that open drainage are where this lands.

What causes gallstones in the first place?

Now the metabolic half, which is usually read backwards. A population cohort study tracked 4,307 people. Of those without a gallbladder, 67.2% had metabolic syndrome, against 51.9% of those who still had one. Moderate-to-severe fatty liver ran 42.7% against 34.2%. Those scans came a median of ten years after surgery. Adjusting for metabolic factors makes both links disappear.

The critic’s reading is fair, and I grant most of it. Only 265 of those people had lost a gallbladder. Fatty liver was graded on ultrasound, not biopsy. One shared cause can produce both the stone and the fatty liver. The conclusion is where I stop. Adjusting for body weight and diabetes removes the effect only if you treat them as confounders (outside factors that skew a result) and not as the path itself. The stone is a symptom of the terrain. The bile was made under high insulin, loaded with cholesterol, in a storage sac rarely asked to empty. A cohort study can adjust that away. A practice walks in with the patient.

Two more drivers sit upstream of the knife. Among people with gallstones, 65.7% report indigestion. That figure comes mostly from studies without proven criteria. The reviewers warned of operations that leave the complaint behind. Then there is the guideline driver. Decades of low-fat advice kept the organ quiet. Yet fat reaching the upper small bowel is what empties it. Bile that sits thickens into sludge. That is a policy failure, not a patient failing. It belongs beside the inflammatory terrain.

What should you ask about your HIDA scan result?

Sluggish liver and congested biliary system cannot be measured. No liver criterion returns a number for either. A real bile duct measurement looks different. One imaging method tracked 14 duct measures. It caught a rising count of narrowed ducts over a median 371 days while blood tests stayed flat.

So ask what method produced your ejection fraction. Ask whether your pain was the classic gallbladder pattern. Ask when any sludge gets rescanned. Settle the plan with the physician who prescribes, since nothing here is a reason to start or stop a medication. The Deep Dive for Chapter 23 lists every study and every number above. It says what each result shows, what it does not, and the one that argues against my own position. What the flora do to appetite comes next.

Frequently asked questions

What is a normal gallbladder ejection fraction?

In 60 healthy volunteers at four centers, the lower limit of normal came out at 38%. How well the test repeated depended on the infusion. The coefficient of variation was 19% with a 60-minute infusion, 52% with the short one, and 35% at 30 minutes. A percentage quoted without its method cannot be read. Ask which method produced yours. Context is what makes a number usable.

Does a low ejection fraction mean I need surgery?

It does not settle it. In 93 patients the number was the same whether the operation helped or not. Classic gallbladder pain predicted relief 22 times over. And 9 of 32 patients with unusual pain got better with no operation. A real gallbladder reason is a good reason to operate. An unclear percentage on its own is not. Imaging findings need a matching clinical picture.

Can a blood test show whether my bile signaling works?

Not reliably. Resting levels of the hormone vary ten-fold between healthy people. They peak 90 to 120 minutes after a meal and vanish on a fast. Fasting is when blood is usually drawn. After gallbladder surgery doubled bile acid production, blood bile acids and fats did not move at all. The routine panel is blind to this system. Measure what responds to treatment instead.

Is gallbladder sludge dangerous?

Mostly it clears. Of the patients followed with repeat scans, 71.4% were clear within about two months. Followed forward, though, 19.6% got stones or other problems. That came from 56 people watched for an average of 20.3 months. It argues for a scheduled repeat scan, not a scalpel or a shrug. Watchful plans need dates, not vibes.

What causes a low gallbladder ejection fraction?

Part of a low number comes from the test itself. The result swings with how the test hormone is dripped in. In healthy volunteers the scatter was 19% with a 60-minute infusion and 52% with the short one. The rest is terrain. Fat reaching the upper gut is what empties the gallbladder. Decades of low-fat advice kept it quiet, so bile sits and thickens.

Can you improve your gallbladder ejection fraction?

Start with the measurement. Ask which infusion method produced your number. A 60-minute infusion scattered far less than the short one most places use. Then look at the terrain. The gallbladder empties when fat reaches the upper small bowel. A storage sac rarely asked to empty turns bile into sludge. Bring your imaging reports and recent labs, so the number is read with its method attached.

Sources

1. Al-Dury, S., Wahlström, A., Panzitt, K., Thorell, A., Ståhlman, M., Trauner, M., Fickert, P., Bäckhed, F., Fändriks, L., Wagner, M., & Marschall, H.-U. (2019). Obeticholic acid may increase the risk of gallstone formation in susceptible patients. Journal of Hepatology, 71(5), 986-991. https://doi.org/10.1016/j.jhep.2019.06.011
2. Barrera, F., Azócar, L., Molina, H., Schalper, K. A., Ocares, M., Liberona, J., Villarroel, L., Pimentel, F., Pérez-Ayuso, R. M., Nervi, F., Groen, A. K., & Miquel, J. F. (2015). Effect of cholecystectomy on bile acid synthesis and circulating levels of fibroblast growth factor 19. Annals of Hepatology, 14(5), 710-721. https://pubmed.ncbi.nlm.nih.gov/26256900/
3. Carr, J. A., Walls, J., Bryan, L. J., & Snider, D. L. (2009). The treatment of gallbladder dyskinesia based upon symptoms: Results of a 2-year, prospective, nonrandomized, concurrent cohort study. Surgical Laparoscopy, Endoscopy & Percutaneous Techniques, 19(3), 222-226. https://doi.org/10.1097/SLE.0b013e3181a74690
4. Janowitz, P., Kratzer, W., Zemmler, T., Tudyka, J., & Wechsler, J. G. (1994). Gallbladder sludge: spontaneous course and incidence of complications in patients without stones. Hepatology, 20(2), 291-294. https://pubmed.ncbi.nlm.nih.gov/8045489/
5. Trivedi, P. J., Arndtz, K., Abbas, N., Telford, A., Young, L., Banerjee, R., Eddowes, P., Jhaveri, K. S., & Hirschfield, G. M. (2024). Quantitative MRCP and metrics of bile duct disease over time in patients with primary sclerosing cholangitis: A prospective study. Alimentary Pharmacology & Therapeutics, 59(11), 1366-1375. https://doi.org/10.1111/apt.17944
6. Latenstein, C. S. S., Alferink, L. J. M., Darwish Murad, S., Drenth, J. P. H., van Laarhoven, C. J. H. M., & de Reuver, P. R. (2020). The association between cholecystectomy, metabolic syndrome, and nonalcoholic fatty liver disease: A population-based study. Clinical and Translational Gastroenterology, 11(4), e00170. https://doi.org/10.14309/ctg.0000000000000170
7. Latenstein, C. S. S., de Jong, J. J., Eppink, J. J., Lantinga, M. A., van Laarhoven, C. J. H. M., de Reuver, P. R., & Drenth, J. P. H. (2019). Prevalence of dyspepsia in patients with cholecystolithiasis: A systematic review and meta-analysis. European Journal of Gastroenterology & Hepatology, 31(8), 928-934. https://doi.org/10.1097/MEG.0000000000001463
8. Lundåsen, T., Gälman, C., Angelin, B., & Rudling, M. (2006). Circulating intestinal fibroblast growth factor 19 has a pronounced diurnal variation and modulates hepatic bile acid synthesis in man. Journal of Internal Medicine, 260(6), 530-536. https://doi.org/10.1111/j.1365-2796.2006.01731.x
9. Ziessman, H. A., Tulchinsky, M., Lavely, W. C., Gaughan, J. P., Allen, T. W., Maru, A., Parkman, H. P., & Maurer, A. H. (2010). Sincalide-stimulated cholescintigraphy: A multicenter investigation to determine optimal infusion methodology and gallbladder ejection fraction normal values. Journal of Nuclear Medicine, 51(2), 277-281. https://doi.org/10.2967/jnumed.109.069393
10. Zhang, J. H., Nolan, J. D., Kennie, S. L., Johnston, I. M., Dew, T., Dixon, P. H., Williamson, C., & Walters, J. R. F. (2013). Potent stimulation of fibroblast growth factor 19 expression in the human ileum by bile acids. American Journal of Physiology. Gastrointestinal and Liver Physiology, 304(10), G940-G948. https://doi.org/10.1152/ajpgi.00398.2012

Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP, board certified in anesthesiology, pain medicine, interventional pain management, addiction medicine and obesity medicine. Adapted from Chapter 23 of The Angry Gut by Dr. Padda and Ami Michelle Grimes. Last reviewed September 2026.