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HelpTest Code HCYSS Homocysteine, Total, Serum
Specimen Type
SerumNecessary Information
Patient's age and sex are required.
Specimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Within 4 hours of collection, centrifuge and aliquot serum into plastic vial.
Specimen Minimum Volume
0.3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 28 days |
| Frozen | 309 days | |
| Ambient | 28 days |
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
| Gross icterus | OK |
Clinical Information
Homocysteine is an intermediary in the sulfur-amino acid metabolism pathways, linking the methionine cycle to the folate cycle. Inborn errors of metabolism that lead to homocysteinemia or homocystinuria include cystathionine beta-synthase deficiency (homocystinuria) and various defects of methionine remethylation. Genetic defects in vitamin cofactors (vitamins B6, B12, and folate) and nutritional deficiency of vitamin B12 and folate also lead to abnormal homocysteine accumulation.
Homocysteine concentration is an indicator of acquired folate or cobalamin deficiency and is a contributing factor in the pathogenesis of neural tube defects. Homocysteine was once thought to be an independent predictor of cardiovascular disease (atherosclerosis, heart disease, thromboembolism), as early observational studies prior to the year 2000 linked homocysteine to cardiovascular risk and morbidity and mortality. However, following US Food and Drug Administration mandated folic acid supplementation in 1998, homocysteine concentrations decreased by approximately 10% without a similar change in cardiovascular or ischemic events. Currently, the use of homocysteine for assessment of cardiovascular risk is uncertain and controversial. Based on several meta-analyses, at present, homocysteine may be regarded as a weak risk factor for coronary heart disease, and there is a lack of direct causal relationship between hyperhomocysteinemia and cardiovascular disease. It is most likely an indicator of poor lifestyle and diet.
This test should be used in conjunction with plasma amino acids, quantitative acylcarnitines, methylmalonic acid, and urine organic acids to aid in the biochemical screening for primary and secondary disorders of methionine metabolism.
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 |
Day(s) Performed
Monday through Friday
Report Available
3 to 5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
83090
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
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)