1. What the test is and why I ordered it

Ultrasound uses sound waves, with no radiation, to look at the kidneys, bladder, and prostate. I order it to check for kidney swelling, stones, or cysts, to measure how well the bladder empties, and to estimate prostate size.

2. What the numbers usually mean

• Hydronephrosis: kidney swelling from a blockage, graded mild to severe.
• Simple kidney cysts: very common and benign.
• Post-void residual (urine left after you go): under about 50 to 100 mL is usually fine. Results repeatedly over about 200 to 300 mL suggest the bladder isn't emptying well.
• Prostate volume: about 20 to 30 mL is typical for a younger adult. Larger glands are common with age, though size doesn't closely match symptoms.
• Bladder wall thickening or pouches (diverticula): can be signs of long-standing blockage.

3. What usually happens next

A complex cyst or solid mass usually needs a CT or MRI. A high residual is often rechecked and paired with a flow test before discussing medication or a procedure. Hydronephrosis leads to finding and fixing its cause.

4. When to call right away

• You cannot urinate, or your bladder feels painfully full
• Fever with flank pain

5. Where to see your result and ask about it

Your actual result, and any note from your care team, is in your patient portal, the same one you use to book visits and send messages. Send questions about your result through the portal, or call the office at (516) 535-1900. If something feels urgent, call the office or go to the nearest emergency room. This page explains what results usually mean; it can't interpret yours.