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HelpTest Code HCYSS Homocysteine, Total, Serum
Reporting Name
Homocysteine, Total, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Useful For
An aid for screening patients suspected of having an inherited disorder of methionine metabolism including:
-Cystathionine beta-synthase deficiency (homocystinuria)
-Methylenetetrahydrofolate reductase deficiency and its thermolabile variants:
-Methionine synthase deficiency
-Cobalamin (Cbl) metabolism
-Combined methyl-Cbl and adenosyl-Cbl deficiencies: Cbl C2, Cbl D2, and Cbl F3 deficiencies
-Methyl-Cbl specific deficiencies: Cbl D-Var1, Cbl E, and Cbl G deficiencies
-Transcobalamin II deficiency
-Adenosylhomocysteinase deficiency
-Glycine N-methyltransferase deficiency
-Methionine adenosyltransferase I/III deficiency
Screening and monitoring patients suspected of, or confirmed with, an inherited disorder of methionine metabolism
Evaluating individuals with suspected deficiency of vitamin B12 or folate
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Necessary Information
Patient's age and sex are required.
Specimen Required
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial within 4 hours of collection.
Specimen Type
SerumSpecimen Minimum Volume
0.3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 28 days | |
| Frozen | 309 days | ||
| Ambient | 28 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
|
Age |
Total Homocysteine (nmol/mL) |
|
|
Female |
Male |
|
|
0-11 months |
3.1-8.3 |
3.2-9.7 |
|
12-23 months |
3.2-8.3 |
3.3-9.6 |
|
24-35 months |
3.2-8.2 |
3.3-9.6 |
|
3 years |
3.2-8.2 |
3.3-9.6 |
|
4 years |
3.3-8.2 |
3.4-9.5 |
|
5 years |
3.4-8.1 |
3.5-9.4 |
|
6 years |
3.5-8.1 |
3.6-9.4 |
|
7 years |
3.5-8.1 |
3.7-9.4 |
|
8 years |
3.6-8.2 |
3.8-9.3 |
|
9 years |
3.7-8.2 |
3.9-9.4 |
|
10 years |
3.8-8.3 |
4.1-9.4 |
|
11 years |
3.9-8.4 |
4.3-9.4 |
|
12 years |
3.9-8.6 |
4.4-9.5 |
|
13 years |
4.0-8.7 |
4.6-9.6 |
|
14 years |
4.1-8.8 |
4.8-9.7 |
|
15 years |
4.2-8.9 |
5.0-9.8 |
|
16 years |
4.2-9.1 |
5.2-9.9 |
|
17 years |
4.3-9.2 |
5.4-10.0 |
|
18 years |
4.3-9.3 |
5.6-10.1 |
|
19 years |
4.4-9.5 |
5.7-10.3 |
|
20 years |
4.4-9.6 |
5.9-10.5 |
|
21 years |
4.4-9.8 |
6.0-10.6 |
|
22 years |
4.4-9.9 |
6.1-10.8 |
|
23 years |
4.4-10.1 |
6.2-11.0 |
|
24 years |
4.4-10.3 |
6.2-11.1 |
|
25 years |
4.4-10.4 |
6.3-11.3 |
|
26 years |
4.4-10.6 |
6.3-11.4 |
|
27 years |
4.3-10.8 |
6.4-11.6 |
|
28 years |
4.3-11.0 |
6.4-11.7 |
|
29 years |
4.3-11.2 |
6.4-11.8 |
|
30 years |
4.3-11.4 |
6.4-11.9 |
|
31 years |
4.4-11.6 |
6.4-12.1 |
|
32 years |
4.4-11.8 |
6.4-12.2 |
|
33 years |
4.4-11.9 |
6.4-12.3 |
|
34 years |
4.5-12.1 |
6.4-12.4 |
|
35 years |
4.5-12.2 |
6.4-12.6 |
|
36 years |
4.6-12.4 |
6.4-12.8 |
|
37 years |
4.6-12.5 |
6.4-12.9 |
|
38 years |
4.7-12.7 |
6.4-13.1 |
|
39 years |
4.7-12.8 |
6.4-13.2 |
|
40 years |
4.8-13.0 |
6.5-13.4 |
|
41 years |
4.8-13.2 |
6.5-13.5 |
|
42 years |
4.8-13.4 |
6.5-13.7 |
|
43 years |
4.9-13.5 |
6.6-13.9 |
|
44 years |
4.9-13.7 |
6.6-14.0 |
|
45 years |
4.9-13.9 |
6.6-14.2 |
|
46 years |
4.9-14.0 |
6.7-14.4 |
|
47 years |
4.9-14.2 |
6.7-14.5 |
|
48 years |
5.0-14.3 |
6.8-14.7 |
|
49 years |
5.0-14.4 |
6.8-14.9 |
|
50 years |
5.0-14.5 |
6.8-15.0 |
|
51 years |
5.1-14.6 |
6.8-15.2 |
|
52 years |
5.1-14.7 |
6.9-15.4 |
|
53 years |
5.1-14.8 |
6.9-15.5 |
|
54 years |
5.2-14.9 |
6.9-15.6 |
|
55 years |
5.2-15.0 |
6.9-15.7 |
|
56 years |
5.3-15.0 |
6.9-15.8 |
|
57 years |
5.3-15.1 |
6.9-15.9 |
|
58 years |
5.3-15.2 |
6.9-16.0 |
|
59 years |
5.4-15.2 |
6.9-16.0 |
|
60 years |
5.4-15.3 |
6.9-16.1 |
|
61 years |
5.4-15.4 |
7.0-16.2 |
|
62 years |
5.5-15.4 |
7.0-16.2 |
|
63 years |
5.5-15.5 |
7.0-16.3 |
|
64 years |
5.6-15.5 |
7.1-16.3 |
|
65 years |
5.6-15.6 |
7.1-16.3 |
|
66 years |
5.7-15.6 |
7.1-16.3 |
|
67 years |
5.7-15.7 |
7.2-16.3 |
|
68 years |
5.8-15.7 |
7.2-16.3 |
|
69 years |
5.9-15.7 |
7.2-16.3 |
|
70 years |
6.0-15.8 |
7.3-16.3 |
|
71 years |
6.1-15.8 |
7.3-16.3 |
|
72 years |
6.2-15.8 |
7.3-16.3 |
|
73 years |
6.3-15.9 |
7.3-16.3 |
|
74 years |
6.4-15.9 |
7.3-16.3 |
|
75 years |
6.5-15.9 |
7.3-16.3 |
|
76 years |
6.6-15.9 |
7.3-16.3 |
|
77 years |
6.7-16.0 |
7.4-16.3 |
|
78 years |
6.8-16.0 |
7.4-16.3 |
|
79 years |
6.9-16.0 |
7.5-16.3 |
|
80 years |
7.0-16.0 |
7.5-16.3 |
|
81 years |
7.1-16.0 |
7.7-16.2 |
|
82 years |
7.2-16.0 |
7.8-16.2 |
|
83 years |
7.2-16.0 |
7.9-16.2 |
|
84 years |
7.3-16.0 |
8.0-16.2 |
|
85 years |
7.3-16.0 |
8.2-16.2 |
|
>85 years |
7.4-16.0 |
8.3-16.2 |
Interpretation
Elevated homocysteine concentrations are considered informative in patients evaluated for suspected nutritional deficiencies (vitamin B12, folate) and inborn errors of metabolism. Measurement of methylmalonic acid (MMA) distinguishes between vitamin B12 (cobalamin) and folate deficiencies, as MMA is only elevated in vitamin B12 deficiency. Treatment response can be evaluated by monitoring serum homocysteine concentrations over time.
Day(s) Performed
Monday through FridayReport Available
3 to 5 daysTest 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
83090
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HCYSS | Homocysteine, Total, S | 13965-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 35836 | Homocysteine, Total, S | 13965-9 |
Forms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-Biochemical Genetics Test Request (T798)
-Cardiovascular Test Request (T724)