5-HIAA
Biochemistry Overview / Directory
Purpose of the test
5-Hydroxy-indole-acetic acid (5-HIAA) is the metabolite of 5-hydroxytryptamine (serotonin). Serotonin is produced by the argentaffin cells of the GI tract.
Serotonin is over-produced in the carcinoid tumours of the GI tract. These are associated with flushing attacks, diarrhoea and abdominal pain. Most carcinoid tumours are metastatic to the liver at the time of detection. Resection of the primary tumour, partial hepatectomy and embolization are the primary forms of treatment, although radiolabelled octreotide has been used more recently. 5-HIAA is invariably increased in classical carcinoid, although some tumours may be non-secretory. 5-HIAA is also increased with high dietary serotonin intake or other GI tract disease e.g. coeliac disease. Dietary restrictions may be necessary prior to urine collections for 5-HIAA.
Sample Requirements
Timed (24h) urine collections are preferred for investigations of adults for phaeochromocytoma or carcinoid syndrome. Samples should be collected into containers with an anti-bacterial agent (boric acid) or into acid containing bottles. Acidification of the sample prior to despatch provides greater stability for the analytes measured. A 10-25 mL aliquot is preferred with the 24h urine volume provided. Note that we do not have reference ranges for 5-HIAA in random samples for either adults or children.
Storage and Transport
Send by overnight first class post.
Turnaround Time
Assays for biogenic amines are carried out weekly and a turnaround time of 1-2 weeks is typical. Markedly abnormal results will be telephoned or Faxed.
Price
Price available on application - please contact adrian.turner@kch.nhs.uk. Discounts could be available for significant workloads.
Contacts
Dr Roy Sherwood Tel: 020 3299 3726 e-mail: roy.sherwood@nhs.net
or
Mr Colin Stone Tel: 020 3299 4128 e-mail: colin.stone@kch.nhs.uk
