Preparing for your ultrasound

You have just left your doctor's office with a requisition form for a "Complete Abdominal Ultrasound." You look at the instructions, and you see words like "fasting required" or "nothing by mouth after midnight."

 

Suddenly, you have questions. Can you drink water? What about your morning coffee? Why does it matter anyway?

 

At Frontier Diagnostics in Guelph, this is the number one question our patients ask when booking this common exam. It is natural to be anxious about medical tests, especially when they involve disrupting your daily routine.

 

The short answer is: Yes, preparation is critical. Following the fasting rules is the single best thing you can do to ensure we get clear, high-quality images so your doctor can make an accurate diagnosis.

 

Here is a simple, physician-approved guide on how to prepare for your abdominal ultrasound, and exactly why we ask you to do it.

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The "Why": Why Do I Have to Fast?

 

It’s not just to make you hungry! We aren't trying to be difficult. There are two primary physiological reasons why an abdominal ultrasound requires an empty stomach:

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1. To Reduce Stomach Gas

 

Ultrasound technology uses high-frequency sound waves to create images of your internal organs. These sound waves travel beautifully through fluid and soft tissue, but they bounce right off air and gas.

 

When you eat, you swallow air. Furthermore, the digestion process creates gas in your stomach and intestines. If your abdomen is full of gas, it acts like a cloudy windshield. It blocks our view of the organs sitting behind the stomach and bowel, such as the pancreas and the aorta. Fasting ensures that "windshield" is clear.

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2. To Inflate the Gallbladder

 

The gallbladder is a small organ located under your liver that stores bile. When you eat something fatty, your gallbladder squeezes that bile out to help with digestion.

 

To get a good look at your gallbladder—to check for stones, sludge, or inflammation—we need it to be full and distended, like an inflated balloon. If you eat breakfast before your scan, your gallbladder will shrink down, making it almost impossible to evaluate properly.

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The Rules: Your Preparation Checklist

 

For a complete abdominal ultrasound (which typically looks at the liver, gallbladder, pancreas, spleen, kidneys, and aorta), standard protocol in Ontario generally requires the following:

• Fast for 8 to 12 hours before your appointment. (For most morning appointments, this means nothing to eat after midnight the night before).

• Do not eat any solid food.

• Do not drink milk, juice, soda, coffee, or tea. Even black coffee can stimulate your digestive system and cause the gallbladder to contract.

• Do not chew gum or suck on hard candies. Chewing gum makes you swallow significantly more air, which fills your stomach with gas and obscures our view.

• Do not smoke before the exam, as this also causes you to swallow air.

 

The Big Questions: Water and Medication

 

This is the area that causes the most confusion.

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Can I drink water? Generally, yes, small sips of plain water are acceptable to keep you hydrated and comfortable. However, avoid gulping large amounts of water right before the exam unless specifically instructed otherwise (some pelvic or renal scans require a full bladder, but a standard abdominal scan does not).

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Should I take my medication? Yes. You should almost always continue to take your prescribed medications as usual with a small amount of plain water.

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Exception: If you are diabetic, please inform our reception staff when you book your appointment. We prioritize booking diabetic patients as early in the morning as possible to minimize disruption to your insulin and blood sugar routines. Follow your doctor's specific advice regarding insulin dosage while fasting.

 

What Happens If I Forget and Eat?

 

We are human; mistakes happen. If you accidentally eat breakfast on the morning of your scan, please call our clinic immediately.

 

Depending on what you ate and when, we may still be able to perform the scan, but it is more likely we will need to reschedule. Trying to scan a patient who has just eaten often results in suboptimal images, and the radiologist may have to recommend you come back for a repeat scan anyway.

 

Summary

 

By following these simple preparation steps, you are playing an active role in your own healthcare. A well-prepared patient means better images, which leads to a more confident diagnosis from your referring physician.

 

Do you have a requisition for an abdominal ultrasound? If you are in Guelph or the surrounding surrounding areas, contact Frontier Diagnostics today to book your appointment. Our compassionate team is here to make the process as smooth and comfortable as possible.

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This blog is for general information only and isn’t intended to be medical advice. Please consult a healthcare provider for any questions or concerns about your own health.