Pathology - 24-hour urine collections (including those for 5-HIAA)

Please read the information and follow the instructions given carefully, as failure to do so may result in an inaccurate result and the need to repeat the test.

What is a 24-hour urine collection?

A 24-hour urine collection is a complete collection of all the urine produced in one 24-hour period. This involves collecting all the urine in a specially provided container, which may contain a preservative. Preservatives are used for some tests to ensure that the substance being tested does not degrade before it can be measured.

Why is a 24-hour urine collection needed?

Urine contains many waste products and chemicals produced by the body. In some situations, measurement of a particular chemical can help in diagnosing or monitoring a condition or disease.

For some tests a random urine sample is adequate, but in others a 24-hour collection is necessary, as it is important to find out how much of the substance is produced in a day.

What do we look for?

The first step with all 24-hour urine samples is to measure the volume of urine that has been provided. This is an important piece of information, as it is needed to calculate the total daily output of the substance under investigation. The sample is then tested in the laboratory, and the results are calculated.

What is a 24-hour urine collection for 5-hydroxyindoleacetic acid (5HIAA)?

Some patients may have higher than normal levels of a substance called 5-hydroxytryptamine in their body. This can occur when a rare type of growth, known as a carcinoid tumour, develops somewhere in the body. This can lead to symptoms such as diarrhoea and facial flushing. 5-hydroxytryptamine is broken down in the body to 5HIAA, which is passed into the urine. Measuring the amount of 5HIAA in a urine sample can help with diagnosing the condition and deciding whether treatment for the underlying condition is needed.

You may have been asked to make urine collections on more than one day because patients often have intermittently raised 5- HIAA levels.

Is there anything I should avoid before 24-hour urine collection for 5HIAA?

Some foods contain a substance related to 5HIAA which can be excreted in the urine and may affect the test results. These foods should be avoided in the 3 days prior and during the 24-hour collection:

• Avocados, bananas, aubergine (eggplant), kiwi fruit, pineapple, plums, walnuts, tomatoes and certain health food supplements containing 5 Hydroxytryptophan
• Avoid all nuts and seeds (including chia seeds) and fruit smoothies

Please write down any medications that you are taking on the request form, especially if they are for high blood pressure or depression.

What you need to do to prepare for this test

You will be given a special container to collect the urine. This may contain a preservative or acid (for example, for the 5HIAA test). It is important that this substance is left in the container and not thrown away. The label will tell you if a preservative is included. Take care not to spill or touch the preservative, as it can irritate or burn the skin. If any is spilled, mop it up with plenty of water. If the preservative comes into contact with your skin, rinse the area thoroughly with lots of water and inform your doctor.

You may find it is helpful to collect your urine in a smaller clean container first and then carefully pour it straight into the larger container you have been given.

When to collect the sample

Choose a convenient time to start the urine collection, such as when you get up in the morning (for example 8am). The collection will then continue for the next 24 hours. Once you have chosen your start time proceed as follows:

Day 1: 8am

• Empty your bladder completely and discard the urine
• After this, collect all urine you pass for the rest of the day into the container

Day 2: 8am

• Empty your bladder completely and add this urine to the container
• Do not add any more urine after this. This completes the 24- hour collection

Storage

Keep the urine container in a cool place throughout the collection period and until it is delivered to the hospital.

If any urine is accidentally discarded during the collection, stop the test and tell the laboratory what has happened. You will be given another container to start again.

After the sample has been collected

Carefully label the container with the following:

• Name (forename and surname)
• Date of birth
• Date and time of collection (start and finish time) and the ward or clinic you are attending (e.g. the Outpatients Department - OPD). Unfortunately, any sample received unlabelled cannot be accepted for analysis

What to do with the collected sample

Deliver the container and the request form if you were given one, as soon as possible after completion to either:

Salford patients should deliver to:
Salford Royal Pathology Laboratory Specimen Reception, Turnberg Building, Level 2, Stott Lane, Salford M6 8HD
Telephone 0161 206 4959

Oldham patients should deliver to:
Royal Oldham Pathology Specimen Reception, Pathology building, Rochdale Road, Oldham, OL1 2JH
Telephone 0161 656 1515

Fairfield patients should deliver to:
Fairfield General Pathology, Broad Oak Suite, Rochdale Road, Bury, BL9 7TD
Telephone 0161 778 2596

Laboratory hours are 8am to 8pm Monday to Sunday.

If you have been instructed to take the container to a ward or clinic, then take the container and request form there.

What are the limitations of this investigation?

The accuracy of the results depends on the quality of your sample, so it is very important that you follow the instructions on collection and delivery of the sample exactly.

Are there any alternatives to this investigation?

There are no alternatives to this test that will give as much information.

What happens to your results?

The results of the analysis will be sent to your doctor, who will explain to you what they mean and what, if any, treatment you may need. Laboratory staff members are not permitted to give you results or discuss the meaning of the results with you.

If you require further information about this test, please contact:

Salford Royal Clinical Biochemistry Department
Salford Royal, Stott Lane, Salford, M6 8HD
Telephone 0161 206 4958 or 0161 206 4959

Royal Oldham Clinical Biochemistry Department
Pathology Building, Rochdale Road, Oldham, OL1 2JH
Telephone 0161 656 1515