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5-HIAA

Source Urine
Mnemonic UHIAA and U24H
Specimen Requirements

Extra-regional sites: see 5-HIAA, Extra-regional

20 mL aliquot of acidified 24 hour urine collection.  Refer to charts in Specimen Handling and Additional Information sections.

Refrigerate during collection.
Urine specimen collection container must have preservative pouch(es) added prior to collection.

Specimen Handling

Acidify specimen in original collection container.

Record 24 hour volume and collection (start and end) dates and time
in the space provided on the requisition.

Mix well and pour off acidified aliquot. 
Sample pH should be less than 3.0.


Collection type

Weight of Sulfamic acid in pouch

 24 hour collections for
newborn up to 4 years		  Use acidification chart in
Additional Information section

24 hour and timed 
collections for
patients > 4 years

  7 g pouch in each 4 liter container collection 

Random collection available for
pediatric (<16) patients only

 Refer patient to ACH

 

 

 

Additional Information

Certain foods and medications may interfere. Patient handout available with collection instructions.  See form #CH3008. 

The following drugs cause physiological interference with the levels of urine 5-HIAA:
Physiological decreases: chlorophenylalanine, corticotropin, guanfacine, imipramine, isocarboxazid, isoniazid, levodopa, MAO inhibitors, methyDOPA, moclobemide, octreotide.
Physiological increases: cisplatin, fluorouracil, melphalan, reserpine, rauwolfia.

For Acidification of Pediatric 24 hour Urines:

 

Age

  Number of 0.5 g pouches of Sulfamic acid 
to add when Acidifying During Collection

Up to 1 month

No preservative required.
Upon receipt in lab, immediately measure volume and aliquot for HIAA and urine creatinine.
Freeze HIAA aliquot; once frozen, send to DSC.

1 up to 2 months

2

2 up to 4 months

3

4 up to 12 months

4

  12 months up to 4 years 

5

 



 







 

Testing Location Analytical Toxicology
Testing Frequency Every two weeks

 
Alternate Name(s) 5-Hydroxyindoleacetic Acid

 
Reference Interval

 24 Hour
 All ages  10-40 µmol/d

 Random

Age 

 µmol/mmol

 0-5 years

<13

 >5 years

 <10