5-Hydroxyindoleacetic Acid, 24 Hour, Urine

Reporting Name

5-Hydroxyindoleacetic Acid, U

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Biochemical diagnosis and monitoring of intestinal carcinoid syndrome using 24-hour urine specimens

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Ordering Guidance

This test is the preferred test for measurement of 5-hydroxyindoleacetic acid concentrations. If a random urine collection is preferred, order HIAAR / 5-Hydroxyindoleacetic Acid, Random, Urine.

Necessary Information

1. Collection duration and urine volume in milliliters are required.

2. Patient's age and sex are required.

Specimen Required

Patient Preparation:

1. Some medications could interfere with test results. The ordering provider should decide if any medications should be stopped and when they should be restarted. If clinically feasible, discontinue the following medications at least 48 hours prior to, as well as during, specimen collection:

-Acetaminophen (Tylenol or generic versions)

-Tryptophan containing supplements

2. For 48 hours prior to, as well as during, the urine collection, the patient should:

Limit the following to one serving per day:

-Fruits

-Vegetables

-Nuts

-Caffeinated beverages or foods

Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 5 mL

Collection Instructions:

1. Add 25 mL of 50% acetic acid as preservative at start of collection. Use 15 mL of 50% acetic acid for children <5 years old.

2. Collect a 24-hour urine specimen.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.

Specimen Type

Urine

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Urine	Refrigerated (preferred)	56 days
	Frozen	365 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Reference Values

	5-HIAA, mg/24 hour 99th percentile cutoff
Age	Female	Male
≤23 months	≤2.7	≤2.3
24-35 months	≤3.0	≤2.6
3 years	≤3.2	≤2.9
4 years	≤3.4	≤3.2
5 years	≤3.6	≤3.6
6 years	≤3.8	≤3.9
7 years	≤4.0	≤4.2
8 years	≤4.2	≤4.5
9 years	≤4.5	≤4.8
10 years	≤4.7	≤5.1
11 years	≤4.9	≤5.3
12 years	≤5.2	≤5.6
13 years	≤5.4	≤5.8
14 years	≤5.6	≤6.1
15 years	≤5.7	≤6.3
16 years	≤5.9	≤6.4
17 years	≤6.0	≤6.6
18 years	≤6.0	≤6.7
19 years	≤6.1	≤6.8
20 years	≤6.1	≤6.9
21 years	≤6.2	≤6.9
22 years	≤6.2	≤7.0
23 years	≤6.2	≤7.0
24 years	≤6.3	≤7.1
25 years	≤6.3	≤7.2
26 years	≤6.3	≤7.2
27 years	≤6.4	≤7.3
28 years	≤6.4	≤7.4
29 years	≤6.5	≤7.5
30 years	≤6.6	≤7.5
31 years	≤6.6	≤7.6
32 years	≤6.7	≤7.7
33 years	≤6.8	≤7.7
34 years	≤6.8	≤7.8
35 years	≤6.9	≤7.9
36 years	≤6.9	≤7.9
37 years	≤7.0	≤8.0
38 years	≤7.0	≤8.1
39 years	≤7.0	≤8.2
40 years	≤7.1	≤8.2
41 years	≤7.1	≤8.3
42 years	≤7.2	≤8.4
43 years	≤7.3	≤8.5
44 years	≤7.4	≤8.6
45 years	≤7.4	≤8.7
46 years	≤7.5	≤8.8
47 years	≤7.6	≤8.9
48 years	≤7.6	≤9.0
49 years	≤7.7	≤9.1
50 years	≤7.7	≤9.2
51 years	≤7.8	≤9.3
52 years	≤7.8	≤9.4
53 years	≤7.9	≤9.5
54 years	≤8.0	≤9.6
55 years	≤8.1	≤9.7
56 years	≤8.1	≤9.7
57 years	≤8.2	≤9.8
58 years	≤8.3	≤9.8
59 years	≤8.3	≤9.8
60 years	≤8.3	≤9.9
61 years	≤8.3	≤9.9
62 years	≤8.4	≤9.9
63 years	≤8.4	≤10.0
64 years	≤8.4	≤10.0
65 years	≤8.4	≤10.0
66 years	≤8.5	≤10.1
67 years	≤8.5	≤10.1
68 years	≤8.5	≤10.1
69 years	≤8.5	≤10.2
70 years	≤8.5	≤10.2
71 years	≤8.6	≤10.2
72 years	≤8.6	≤10.2
73 years	≤8.5	≤10.1
74 years	≤8.5	≤10.1
75 years	≤8.6	≤10.1
76 years	≤8.6	≤10.0
77 years	≤8.6	≤10.0
78 years	≤8.6	≤10.0
79 years	≤8.6	≤10.0
80 years	≤8.7	≤9.9
81 years	≤8.7	≤9.9
82 years	≤8.7	≤9.9
83 years	≤8.7	≤9.9
84 years	≤8.7	≤9.9
85 years	≤8.6	≤9.8
86 years	≤8.5	≤9.8
87 years	≤8.4	≤9.7
88 years	≤8.3	≤9.7
89 years	≤8.1	≤9.5
90 years	≤7.9	≤9.4
91 years	≤7.6	≤9.2
92 years	≤7.4	≤9.0
93 years	≤7.1	≤8.8
94 years	≤7.0	≤8.7
= 95 years	≤6.9	≤8.6

For SI unit Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Interpretation

If pharmacological and dietary artifacts have been ruled out, an elevated excretion of 5-hydroxyindoleacetic acid is a probable indicator of the presence of a serotonin-producing tumor.

Day(s) Performed

Monday through Friday

Report Available

2 to 4 days

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

83497

LOINC Code Information

Test ID	Test Order Name	Order LOINC Value
HIAA	5-Hydroxyindoleacetic Acid, U	1695-6

Result ID	Test Result Name	Result LOINC Value
9248	5-Hydroxyindoleacetic Acid, U	1695-6
TM35	Collection Duration	13362-9
VL33	Urine Volume	3167-4

Forms

If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.

Special Instructions

Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens

Urine Preservative Collection Options

Note: The addition of preservative must occur prior to beginning the collection.

Ambient (no additive)	No
Refrigerate (no additive)	OK
Frozen (no additive)	OK
50% Acetic Acid	Preferred
Boric Acid	OK
Diazolidinyl Urea	No
6M Hydrochloric Acid	OK
6M Nitric Acid	OK
Sodium Carbonate	OK
Thymol	OK
Toluene	OK

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Test Code Billings Clinic: 8900 Mayo: HIAA 5-Hydroxyindoleacetic Acid, 24 Hour, Urine