5-HIAA 24-hour urine test
Quick answer: A 5-HIAA test measures a breakdown product of serotonin in a 24-hour urine collection. Doctors order it when they suspect or are following up a carcinoid (neuroendocrine) tumour.
- Sample24-hour urine
- Takes24 hours of collection at home
- Before the testSome foods (such as bananas, pineapple, tomatoes, avocado, walnuts) and some medicines can affect the result, so follow your doctor's instructions and tell them what you take.
How the test is done
- 1Your doctor explains which foods and medicines to avoid for a few days
- 2You collect a container, often with a preservative, from the lab
- 3You collect all urine for 24 hours, starting after the first morning urine
- 4You return the container with a note of the start and end times
What your results can mean
Reading your report
Normal ranges differ between labs and by age and sex, so discuss your result with your doctor.
If the result is outside the usual range
A high level can be seen with some neuroendocrine (carcinoid) tumours, but certain foods and medicines can also raise it. A normal result does not rule out every type of tumour.
Who usually has this test
People with symptoms such as flushing and diarrhoea that suggest a carcinoid tumour, or people being followed after treatment.
Risks and aftercare
There are no physical risks; follow the diet advice carefully so the result can be read properly.
Names and options
Also called: 5-hydroxyindoleacetic acid, 5HIAA
Listed by the hospital as
- 5-HIAA 24 HRS URINE
Questions about this test
Which foods should I avoid before a 5-HIAA test?
Bananas, pineapple, plums, kiwi, tomatoes, avocado, aubergine and walnuts are commonly listed. Your doctor will tell you how many days before and during the collection to avoid them.
What symptoms lead doctors to order a 5-HIAA test?
It is usually ordered for flushing of the face, diarrhoea, wheezing or a heart valve problem that could come from a carcinoid tumour. It is also used to follow known tumours.
Can medicines affect the 5-HIAA result?
Yes, some cough medicines, pain relievers and other drugs can change the level. Tell your doctor everything you take, but do not stop any medicine unless they advise it.
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Tamara Hospital & IVF Centre, Rajajinagar
34/3, 10th Cross Road, opp. Vardhaka Sardar Patel School, 1st N Block, 2nd Stage, Rajajinagar, Bengaluru 560010
The hospital is open 24 hours. Call before you come to check the timing for your scan or sample collection.
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This page explains each test in general terms so you know what to expect. It is not medical advice: your doctor decides which tests you need and what your results mean. Reference ranges differ between laboratories. Updated 4 November 2026.