How to do a Midstream Urine Sample (MSU)

Why do I need a midstream urine sample?

Your doctor, nurse or midwife may ask for a midstream urine sample to check for:

• Urinary tract infections (UTIs)
• Kidney problems
• Blood, protein or sugar in the urine
• Pregnancy or other medical conditions

Collecting the middle part of your urine stream helps reduce contamination from bacteria or cells normally found around your urethra (urine outlet).

✅ Before you begin:

• Use the sterile container provided by your healthcare provider or pharmacy.
• Wash your hands thoroughly with soap and water and dry them before starting.
• If possible, avoid collecting the sample during menstruation. If unavoidable, inform the healthcare provider.

For women:

1. Wash your hands with soap and warm water. Dry with a clean towel or tissue.
2. Clean your genital area: Use a disposable wipe or clean flannel. Gently part the labia (folds of skin) and wipe from front to back. Use a fresh wipe or cloth for each stroke if needed.
3. Begin to urinate into the toilet for a second or two.
4. Without stopping the flow, hold the sterile container in one hand and pass it into the stream to collect the middle portion of urine (about halfway through peeing).
5. Once the container is about half full (usually 30–60ml), remove it from the stream and finish urinating into the toilet.
6. Replace the lid securely on the container without touching the inside. Wash your hands again.

For men:

1. Wash your hands thoroughly with soap and water.
2. Retract the foreskin (if present) and clean the tip of the penis using a disposable wipe or clean cloth.
3. Begin urinating into the toilet to start the stream.
4. Without stopping the flow, collect the middle portion of urine in the sterile container.
5. Fill it to the marked line or about halfway (usually 30–60ml).
6. Finish urinating into the toilet, and secure the lid on the sample container. Wash hands again.

After collecting the sample:

• Label the container clearly with your name, date of birth, and the date/time of collection if not already pre-labelled.
• Return the sample as soon as possible, ideally within 2 hours. If there’s a delay, store the container in the fridge (not freezer) and bring it in within 4 hours.

⚠️ Important reminders:

• Do not touch the inside of the lid or container.
• Avoid letting the container touch your skin or clothing during collection.
• If you can’t produce urine at the time requested, let your clinician know.

UK References:

• NHS England. Urine tests. https://www.nhs.uk/conditions/urine-test/
• NICE Clinical Knowledge Summary. Urinary tract infection (lower) – women. https://cks.nice.org.uk/topics/uti-lower-women/
• Public Health England (now UKHSA). Diagnostic Urine Specimen Collection Guidelines. (Laboratory Standards for Urine Samples)