Key Takeaways
- Ultrasound preparation varies by scan type: abdominal ultrasounds require 6 to 8 hours of fasting, pelvic ultrasounds require a full bladder, and thyroid or musculoskeletal ultrasounds typically require no preparation at all
- For a full bladder preparation, drink 1 to 1.5 liters of water approximately 1 hour before your appointment and avoid urinating until after the scan is complete
- Wear loose, comfortable, two-piece clothing to your appointment so the sonographer can easily access the area being scanned without requiring you to change into a gown
- Most medications can be taken as normal before an ultrasound, but if your scan requires fasting, swallow pills with only a small sip of water and avoid liquid medications unless approved by your doctor
- Arriving 10 to 15 minutes early with your doctor's referral, insurance card, and any previous imaging results helps ensure a smooth and timely ultrasound appointment at DCDC
Proper preparation is one of the most important factors in obtaining clear, diagnostic-quality ultrasound images. Unlike X-rays or CT scans, ultrasound relies on sound waves that must pass through tissue without interference from gas or an empty organ, so what you eat, drink, and wear before your appointment directly affects image quality. Incorrect preparation is the most common reason scans need to be repeated. This guide explains exactly how to prepare for an ultrasound based on the type of scan you are having, so you arrive ready for the best possible results.
Below you will find detailed ultrasound preparation instructions organized by scan type, including fasting requirements, water intake guidelines, clothing recommendations, medication advice, and a practical day-of checklist. All recommendations reflect the clinical protocols followed at Doctors Clinic Diagnostic Center (DCDC) in Dubai Healthcare City.
General Ultrasound Preparation Rules
While specific preparation instructions depend on the type of ultrasound you are having, several general principles apply to virtually every ultrasound examination. Understanding these universal rules provides a solid foundation before you review the scan-specific instructions that follow.
First, always confirm your preparation instructions with the imaging center when you book your appointment. Preparation protocols can vary slightly between facilities, and the instructions given to you at the time of booking take priority over any general advice you find online. At DCDC, patients receive clear preparation instructions by phone, WhatsApp, or email at the time of scheduling, and our reception team is available to answer any follow-up questions.
Second, timing matters. If your scan requires fasting or a full bladder, coordinate the timing of your last meal or water intake with your appointment time. Drinking water three hours before a pelvic ultrasound rather than one hour before may result in a bladder that has already partially emptied by scan time.
"The most common reason we need to reschedule or repeat an ultrasound is incorrect preparation," says Dr. Osama Elzamzami, Head of Radiology at DCDC. "When patients follow the preparation instructions carefully, we get clear images on the first attempt, which means faster results and a better experience for everyone."
Third, bring your referral letter and any previous imaging. Your doctor's referral tells the sonographer which organs to evaluate, and prior images allow the radiologist to compare findings over time.
Fourth, avoid applying lotions, creams, or powders to the skin over the area being scanned. These products interfere with the ultrasound gel's ability to transmit sound waves. The sonographer will apply a water-based gel at the start of the exam.
Preparation by Ultrasound Type
Different ultrasound examinations have different preparation requirements because the organs being scanned respond differently to food, water, and gas. The table below provides a quick-reference summary, followed by detailed instructions for each scan type.
| Ultrasound Type | Fasting Required | Full Bladder Required | Special Instructions |
|---|---|---|---|
| Abdominal (liver, gallbladder, pancreas, spleen) | Yes — 6 to 8 hours | No | Avoid carbonated drinks and chewing gum for 6 hours before the scan |
| Pelvic (uterus, ovaries, bladder, prostate) | No | Yes — drink 1-1.5L water 1 hour before | Do not urinate after drinking until the scan is complete |
| Thyroid and neck | No | No | Wear a top with an open neckline; remove necklaces |
| Pregnancy (obstetric) | No (first trimester: full bladder may be requested) | First trimester only | Drink 500 mL water 1 hour before if first trimester |
| Renal (kidneys and urinary tract) | Mild fasting preferred (4-6 hours) | Yes — moderately full | Drink 500 mL to 750 mL water 1 hour before the scan |
| Musculoskeletal (joints, tendons, muscles) | No | No | Wear clothing that allows easy access to the joint or limb |
| Breast | No | No | Avoid applying deodorant, powder, or lotion to the chest or underarm area |
| Scrotal / Testicular | No | No | No special preparation required |
| Doppler (vascular — legs, neck, abdomen) | Abdominal Doppler: 6 hours fasting; Leg/neck Doppler: none | No | Avoid caffeine for 4 hours before vascular Doppler scans |
Summary of preparation requirements by ultrasound type. Always confirm instructions with your imaging center at the time of booking.
Abdominal Ultrasound Preparation
An abdominal ultrasound examines the liver, gallbladder, pancreas, spleen, kidneys, and aorta. The gallbladder is the organ most affected by preparation: after eating, it contracts to release bile and appears small and collapsed, potentially hiding gallstones or wall thickening. Fasting for 6 to 8 hours allows the gallbladder to fill with bile and distend to its natural size, giving the sonographer a clear view.
During the fasting period, avoid all food, milk, juice, and sugary drinks. Small sips of plain water are permitted to take essential medications. Do not chew gum or smoke, as both cause air swallowing and gastric secretions that increase intestinal gas — the biggest enemy of abdominal ultrasound because gas scatters sound waves and obscures the organs behind it. If your appointment is in the morning, simply fast overnight after dinner.
Pelvic Ultrasound Preparation
A pelvic ultrasound evaluates the uterus, ovaries, and fallopian tubes in women, or the prostate and seminal vesicles in men. The fluid-filled bladder serves as an acoustic window, pushing bowel gas aside and allowing sound waves to reach the pelvic organs clearly. An empty bladder collapses and provides no window, making it difficult to visualize these structures.
To achieve a full bladder, drink 1 to 1.5 liters (approximately 4 to 6 glasses) of plain water over a 15- to 20-minute period, starting approximately 1 hour before your appointment. Do not urinate after you begin drinking until the sonographer tells you the transabdominal portion of the scan is complete. If you are also having a transvaginal ultrasound, you will empty your bladder after the transabdominal images are obtained.
Thyroid Ultrasound Preparation
A thyroid ultrasound requires no fasting and no full bladder. The thyroid gland sits superficially in the front of the neck and is easily accessible with an ultrasound probe placed directly on the skin. The only practical preparation is to wear a top with an open or low neckline, such as a V-neck or button-down shirt, so the sonographer can access the neck without difficulty. Remove necklaces, scarves, and high-collared garments before the scan. The examination is painless and typically takes 15 to 20 minutes.
Pregnancy (Obstetric) Ultrasound Preparation
Preparation depends on the trimester. During the first trimester (up to 12 weeks), the uterus is small and deep in the pelvis, so a moderately full bladder is requested. Drink approximately 500 mL (two glasses) of water about 1 hour before your scan. In the second and third trimesters, the enlarged uterus rises out of the pelvis and the amniotic fluid provides an excellent acoustic window, so no bladder preparation is needed. Eat and drink normally before a mid- or late-pregnancy scan.
Renal Ultrasound Preparation
A renal ultrasound evaluates the kidneys, ureters, and bladder. Mild fasting of 4 to 6 hours is preferred to reduce bowel gas that can obscure the kidneys. A moderately full bladder is also helpful for assessing the bladder wall and post-void residual volume. Drink approximately 500 mL to 750 mL of water about 1 hour before your appointment. The goal is a comfortably full bladder, not an uncomfortably distended one.
Fasting Requirements: When and How Long
Fasting before an ultrasound serves two purposes: it keeps the gallbladder distended with bile for optimal visualization, and it reduces gas and food residue in the stomach and intestines that block the ultrasound beam. Not all ultrasounds require fasting, but when fasting is necessary, following the instructions precisely makes a significant difference in image quality.
For a standard abdominal ultrasound, fast for 6 to 8 hours before your appointment. This means no food, milk, juice, tea, coffee, or flavored drinks. Plain water in small sips is the only exception, and only if needed to take essential medication. Avoid chewing gum and smoking, as both stimulate gastric secretions and air swallowing. Carbonated beverages must be avoided for at least 6 hours because dissolved carbon dioxide expands in the stomach and creates acoustic interference.
For a renal ultrasound, a lighter fasting period of 4 to 6 hours is typically sufficient. The kidneys are retroperitoneal organs (located behind the intestines), so moderate bowel gas reduction is helpful but the gallbladder is not the primary focus.
For an abdominal Doppler ultrasound (aorta, mesenteric arteries, portal vein), fasting for 6 hours is required. Eating triggers increased mesenteric blood flow and can alter the hemodynamic measurements being evaluated.
"Fasting is not about discomfort — it is about diagnostic accuracy," says Dr. Osama Elzamzami, Head of Radiology at DCDC. "A full gallbladder and a gas-free abdomen allow us to see structures clearly and give you a definitive answer on the first visit, rather than asking you to come back for a repeat scan."
If you have diabetes or another condition that makes prolonged fasting inadvisable, inform the imaging center when booking. Your appointment can be scheduled as the first scan of the morning to minimize fasting duration.
Water Intake: Full Bladder Preparation
A full bladder is essential for certain ultrasound examinations because it acts as an acoustic window that transmits sound waves efficiently to the pelvic organs behind it. Without this window, bowel gas scatters the ultrasound beam and clear images become impossible. The full bladder also pushes the uterus and ovaries into a more favorable scanning position.
The standard protocol is to drink 1 to 1.5 liters of plain water over 15 to 20 minutes, beginning approximately 1 hour before your appointment. Timing is critical: drink too early and the water passes through your kidneys before the scan; drink too late and your bladder will not be sufficiently full.
- Pelvic ultrasound: Drink 1 to 1.5 liters of water starting 1 hour before the scan. Do not urinate after you begin drinking.
- First-trimester pregnancy ultrasound: Drink approximately 500 mL (2 glasses) of water starting 1 hour before the scan.
- Renal ultrasound: Drink 500 mL to 750 mL of water starting 1 hour before the scan for a moderately full bladder.
- Abdominal ultrasound: A full bladder is generally not required. Do not drink large amounts of water if you are fasting for an abdominal scan.
Drink only plain water — not tea, coffee, juice, or carbonated drinks. Caffeine is a mild diuretic that may cause you to need the bathroom before your scan. Carbonated water introduces gas into the stomach, and juice or milk can stimulate gastric activity.
If you arrive and cannot hold your bladder any longer, inform the reception staff immediately so your scan can be prioritized. If you must urinate before the scan, the sonographer may ask you to partially empty and then drink more water to refill — less than ideal, but better than scanning with an empty bladder.
Book Your Ultrasound at DCDC
At Doctors Clinic Diagnostic Center in Dubai Healthcare City, our radiology team provides expert ultrasound scan imaging with advanced equipment and experienced specialists. Receive clear preparation instructions and same-day results.
What to Wear to Your Ultrasound
What you wear to your ultrasound appointment directly affects your comfort and the efficiency of the examination. The sonographer needs to apply gel and place the probe directly on your skin, so the relevant body area must be easily accessible without requiring a full change of clothing.
The best approach is to wear loose, comfortable, two-piece clothing. A separate top and bottom allows the sonographer to expose only the area needed while you remain otherwise clothed. For an abdominal or pelvic ultrasound, a loose shirt and elastic-waist pants or skirt are ideal. For a thyroid ultrasound, a V-neck or button-down shirt provides easy neck access.
- Abdominal / Pelvic: Loose top and elastic-waist pants or skirt. Avoid belts, high-waisted jeans, or tight waistbands.
- Thyroid / Neck: V-neck or open-collar top. Remove necklaces and scarves before the scan.
- Pregnancy: Comfortable two-piece maternity clothing. A loose dress is also acceptable as the sonographer only needs access to your abdomen.
- Breast: A separate top and bra that are easy to remove. Avoid applying deodorant, powder, or lotion to the chest and underarm area on the day of the scan.
- Musculoskeletal (shoulder, knee, ankle): Clothing that allows the joint or limb to be exposed easily. Shorts for knee or ankle scans; a sleeveless or loose-sleeved top for shoulder scans.
Avoid wearing jewelry over the scan area, as it will need to be removed. At DCDC, a gown is available if your clothing does not allow adequate access, but wearing the right clothes usually eliminates the need for one.
Medications Before an Ultrasound
In most cases, you can and should continue taking your regular medications before an ultrasound. Because ultrasound does not involve sedation, contrast injections, or radiation, there are very few medication-related restrictions. However, there are practical considerations depending on whether your scan requires fasting.
If your ultrasound does not require fasting (thyroid, breast, musculoskeletal, or second/third-trimester pregnancy scan), take all medications as prescribed at their normal times with no restrictions.
If your ultrasound requires fasting (such as an abdominal ultrasound), you can still take essential medications. Swallow tablets and capsules with a small sip of water only — approximately 30 to 50 mL, not a full glass. This small amount will not affect your fasting status or image quality. Avoid liquid medications, syrups, and suspensions during fasting if possible, as these can stimulate gastric secretions. If you take a liquid medication that cannot be skipped, inform the imaging center when you book so they can advise on timing.
- Blood pressure medication: Take as normal with a small sip of water, even if fasting.
- Diabetes medication (oral): Consult your doctor. Metformin and sulfonylureas may need timing adjustment if you are fasting for an extended period.
- Insulin: Consult your doctor for dose adjustments during fasting. An early morning appointment is strongly recommended for insulin-dependent patients.
- Thyroid medication: Take as normal with a small sip of water.
- Pain medication: Take as needed with a small sip of water. Anti-gas medications (simethicone) are actually beneficial and can be taken before abdominal ultrasound to reduce intestinal gas.
- Anticoagulants (blood thinners): Take as normal. These do not affect ultrasound imaging.
If you are unsure whether a specific medication will affect your ultrasound, contact the imaging center or your doctor before your appointment. It is better to ask in advance than to skip a medication unnecessarily.
Day-of Checklist for Your Ultrasound
Use this checklist on the day of your ultrasound appointment to ensure everything is in order.
- Confirm your preparation: Verify whether you need to fast, drink water for a full bladder, or both. Check the timing relative to your appointment time.
- Take your medications: Continue essential medications as normal. If fasting, swallow tablets with only a small sip of water.
- Dress appropriately: Wear loose, comfortable, two-piece clothing that allows easy access to the scan area. Avoid tight waistbands, belts, and jewelry over the scan area.
- Skip lotions and creams: Do not apply lotion, cream, or powder to the skin over the area being scanned. For breast ultrasound, avoid deodorant and antiperspirant.
- Bring your referral letter: Have your doctor's referral or request form, either printed or as a digital copy on your phone.
- Bring your insurance card or ID: Your Emirates ID and insurance card (if applicable) are needed for registration.
- Bring previous imaging: If you have had prior ultrasound, CT, or MRI scans of the same area, bring the reports or CDs so the radiologist can compare findings.
- Arrive 10 to 15 minutes early: This allows time for registration, confirmation of preparation, and any last-minute questions before your scan.
- Prepare questions: Write down any questions you want to ask the sonographer or radiologist about the procedure, timeline for results, or follow-up steps.
Patient Tip: How Preparation Made the Difference
A 38-year-old patient came to DCDC for an abdominal ultrasound to investigate persistent upper abdominal pain. She had already had a scan at another clinic the previous week, but the report stated the gallbladder was "suboptimally visualized due to non-fasting status" and the results were inconclusive. When she booked at DCDC, the reception team explained the fasting requirements clearly. She scheduled an early morning appointment, fasted overnight, and arrived well-prepared.
"The difference was immediately apparent," says Dr. Osama Elzamzami, Head of Radiology at DCDC. "Her gallbladder was fully distended, and we identified multiple small gallstones and early wall thickening that had been completely missed on the non-fasting scan. The surgeon had the information needed to plan treatment the same day. This is why we emphasize preparation — it is not a formality, it is a medical necessity."
Schedule Your Ultrasound at DCDC Dubai Healthcare City
DCDC offers a comprehensive range of diagnostic ultrasound services with experienced radiologists, advanced equipment, and same-day results. Our team provides clear preparation instructions tailored to your specific scan to ensure the best image quality on your first visit.
Or WhatsApp us for preparation instructions specific to your scan type.
Frequently Asked Questions
Final Thoughts
Proper preparation is the foundation of a successful ultrasound examination. Whether you need to fast for an abdominal scan, drink water for a pelvic scan, or simply wear the right clothing for a thyroid check, following your preparation instructions ensures the clearest possible images and an accurate diagnosis on your first visit. The small effort of preparing correctly saves you the inconvenience, cost, and delay of a repeat scan.
At Doctors Clinic Diagnostic Center (DCDC) in Dubai Healthcare City, our radiology team provides personalized preparation instructions, experienced sonographers, and consultant radiologists who deliver same-day reports. If you have questions about how to prepare for an ultrasound, our team is available by phone or WhatsApp. For more information, visit our complete ultrasound guide or our ultrasound cost in Dubai article.
Sources & References
This article was reviewed by our medical team and references the following sources:
- American College of Radiology (ACR) — ACR Appropriateness Criteria: Ultrasound Guidelines
- RadiologyInfo.org — Ultrasound: General Information and Patient Preparation
- NHS — Ultrasound Scan: How to Prepare
- American Institute of Ultrasound in Medicine (AIUM) — Practice Parameters for the Performance of Diagnostic Ultrasound Examinations
Medical content on this site is reviewed by DHA-licensed physicians. See our editorial policy for more information.
Written by
Dr. Osama Elzamzami
Diagnostic Radiology
MD, FRCR
Dr. Osama Elzamzami is a Consultant Radiologist and Head of Radiology at DCDC Dubai Healthcare City, specializing in diagnostic imaging including ultrasound, CT, MRI, and interventional radiology.