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This page provides information for an adult to perform an accurate Mid-Stream Sample of Urine (MSSU). This can then be tested by the microbiology laboratory.

What is a MSSU?

A MSSU is the middle part of your urine stream, passed in a single urination, which is required for testing.

Why is a mid-stream urine sample needed?

A sample of urine is needed to find out which, if any, germs are present. If a Urinary Tract Infection (UTI) is identified, the appropriate antibiotic treatment can be given.

When can a sample of urine be taken?

It is best to collect a sample of urine when the bladder feels full. It is often recommended to collect the sample the first time you pass urine in the morning.

Equipment needed to collect a MSSU

  • Sterile pot (will be provided by the person requesting the specimen).
  • Red topped (lidded) urine container containing boric acid (this is a preservative). Do not swallow or tip out the contents from the container.
  • Laboratory request form.
  • Plastic specimen bag.
  • Bedpan/urine bottle (optional).

How to collect a MSSU for laboratory testing

Clean your hands with soap and water before collecting the MSSU. The urine sample should be collected in a clean, sterile container, free from detergents. The sample should not be collected in a pulp bed pan or any other container made from pulp as this can affect the result.

The first quantity (stream) of urine that is passed may be contaminated with germs from the skin. Urine is normally sterile (no germs present).

Do not open the sterile pot or red topped (lidded) urine container until you are ready to collect the urine sample as this can also contaminate the sample.

Instructions for women:

  1. It is advised to hold open the labia (entrance to the vagina) and pass some urine into the toilet (about 15 to 30 mls). Then without stopping the flow of urine, pass urine into the sterile pot (supplied by the nurse or doctor). Some women might find this difficult, therefore, placing a sterile pot inside a bed pan can help to collect a sample.
  2. Once the pot is near full, finish passing the rest of the urine into the toilet.

Instructions for men:

  1. Retract the foreskin.
  2. Pass the first part of the stream of urine (about 15 to 30 mls) into a urinal, toilet or bedpan/bottle.
  3. Place the sterile container (supplied by the nurse or doctor) into the urine stream without interrupting the flow. Collect the mid-stream part of the urine.
  4. Continue the remaining part of the urine stream into the urinal, toilet or bedpan/bottle.

After the procedure

  1. Transfer the MSSU into the red topped (lidded) urine container containing boric acid. Screw the lid on tightly. The container does not need to be filled to the top; a line on the sticker will indicate the ideal amount of urine. However, the minimum amount required is that the container is half filled. If this is difficult, check with your nurse or doctor.
  2. The sticker on the pot should be labelled with your name, date of birth and the date and time of when the sample was taken. The nurse will add your hospital number.
  3. Put the sample inside the plastic specimen bag.
  4. Wash your hands with soap and water.
  5. Take the MSSU to your GP’s surgery or laboratory as soon as possible. The sooner the sample is given in, the more accurate the result will be.

Results

Your GP should receive the results in 4 days.

Sometimes the results can come back contaminated. This may be because of contamination from your skin or from using an unsterile sample container. To avoid this please follow the instructions within this page carefully.

Contact information

Gloucestershire Continence Service

Cheltenham General Hospital

Sandford Road

Cheltenham GL53 7AN

Tel 0300 422 5305

Monday to Friday, 9:00am to 4:00pm

Email: ghn-tr.gloscontinenceservice@nhs.net

Printable version of this page

Collection of MSSU GHPI1185_04_24 Department: Urology Review due: April 2027 PDF, 326.6 KB, 4 pages
Reference number GHPI1185_04_24
Department Urology
Review due April 2027