A Patient’s Story
When Sarah arrived for her abdominal ultrasound, she looked slightly anxious. “I wasn’t sure if I was supposed to eat breakfast,” she said, clutching a half-finished coffee. It’s a common moment we see in clinic: patients trying to do the right thing, but unsure whether fasting will affect the results. Her question, though simple, is an important one. Knowing when to fast and when not to can make a real difference to how clear the scan images turn out.
When Fasting Helps and When It Doesn’t
Not every ultrasound requires fasting. In fact, for many patients, you can eat and drink normally right up until the appointment. However, there are a few specific situations where fasting is essential for accuracy, particularly if your scan focuses on the gallbladder, liver, or pancreas.
When you eat, your gallbladder contracts to help digest fat. If you arrive for your scan after a meal, the gallbladder may be partly or completely empty, which can make it difficult to assess its size, wall thickness, or the presence of stones or sludge.
That’s why, at LSDC, we usually recommend fasting for about 8 hours before gallbladder or upper abdominal scans. This allows the gallbladder to fill fully with bile, providing a clear, diagnostic image.
Fasting also reduces gas and air bubbles in your stomach and small intestine. Excess gas can block the ultrasound waves, especially when we’re trying to visualise deeper organs such as the pancreas.
On the other hand, if the ultrasound is being done for other reasons, for example, to assess your kidneys, bladder, or lower abdomen: fasting is not necessary. In fact, for pelvic or bladder-focused imaging, we’ll often ask you to have a comfortably full bladder instead. A full bladder helps lift the bowel loops out of the way and acts as a window, improving visibility.
What You Can Do Before Your Scan
Here’s a simple breakdown of what most patients should do:
If your scan includes the gallbladder, liver, or pancreas:
Avoid all food and drinks (except small sips of water) for 8 hours before your appointment.
You can take essential medications with a little water unless told otherwise.
Avoid chewing gum, mints, or smoking before your scan, as these can trigger digestion and contract the gallbladder.
If your scan is focused on the kidneys, bladder, or lower abdomen:
No fasting is required.
Drink 3–4 glasses of water one hour before your appointment.
Try not to empty your bladder until after the scan.
If you’re unsure which type of scan you’re having, you can always call the clinic ahead of time. Our team will confirm the preparation that’s right for you.
Why Fasting Matters for Clear Images
Ultrasound waves travel best through fluid and soft tissue, but they can’t pass through air or gas. When your stomach or intestines are full of food or gas, it scatters the sound waves and creates shadows; this can hide small stones, cysts, or even subtle inflammation.
Fasting keeps the stomach and upper small intestine as empty as possible, giving your doctor a clearer window to see the underlying organs. The difference between a fasted and a non-fasted scan can sometimes mean spotting a tiny gallstone versus missing it entirely.
FAQ's
Can I drink water before my abdominal ultrasound?
Can I drink coffee or tea?
What if I accidentally eat something before the scan?
Do I need to fast for a kidney or bladder ultrasound?
Can I take my medication before the scan?
Does fasting mean I can’t even chew gum or suck on sweets?
How will I feel during the scan?
A Word from LSDC
At LSDC, our approach is simple: clarity, comfort, and confidence.
Before every abdominal ultrasound, our clinical team explains exactly how to prepare so your scan produces the most accurate images possible. Whether it’s a full upper abdominal study or a focused gallbladder assessment, our sonographers are highly experienced in producing crystal-clear diagnostic images even in technically challenging cases.
We believe preparation shouldn’t be stressful. That’s why every patient at LSDC receives personalised pre-scan instructions based on their test type and medical background – no guesswork, no unnecessary fasting.
If you’re preparing for an abdominal ultrasound and aren’t sure whether you should fast, reach out to us before your appointment. A few simple steps can make a big difference in getting a reliable result.