Homocysteine

Test code

31789

CPT code(s)*

83090

**CPT Code is subject to a Medicare Limited Coverage Policy and may require a signed ABN when ordering.

Not offered in Quest Diagnostics Nichols Institute (IFD) – San Juan Capistrano. Please provide Service Area Information to find available tests you can order.

In-home collection is not available in your area through Quest Mobile.

Clinical significance

Homocysteine - An elevated concentration of homocysteine is an independent risk factor for cardiovascular disease. When used in conjunction with methylmalonic acid (MMA), these tests are useful to diagnose and monitor vitamin B12 (cobalamin) and folic acid deficiency and are often useful in evaluating macrocytosis (an elevated MCV, an erythrocytic index).

Test resources

None found for this test
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Details

Test details

Methodology

Enzymatic

Specimen requirements
Patient preparation	None Specified
Preferred specimen(s)	1 mL serum
Alternative specimen(s)	Plasma collected in: Sodium heparin (green-top) tube or EDTA (lavender-top) tube
Minimum volume	0.5 mL
Collection instructions	⁠⁠⁠⁠⁠⁠⁠Red-top tubes (no gel): Place the specimen in the refrigerator or ice bath for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation. Transfer the serum to a plastic specimen transport tube. Mark the specimen type as serum on the transport tube. Barrier gel separator tubes: Place the specimen in a refrigerator for 30 minutes after collection. Do not place barrier tubes in an ice bath as freezing may prevent the barrier gel from adequately separating from cells. Centrifuge specimen as soon as possible after complete clot formation, ensuring that the barrier gel completely separates serum from cells. EDTA or heparin tubes: Place the specimen in the refrigerator or ice bath after collection. Centrifuge the specimen as soon as possible. Transfer the plasma to a plastic specimen transport container. Mark the specimen type as plasma on the transport tube. Do not submit whole blood. Note: It is very important to centrifuge and separate serum or plasma from red blood cells as soon as possible to avoid falsely elevated results.
Transport container	Transport tube
Transport temperature	Room temperature
Specimen stability	Room temperature: 4 days Refrigerated: 14 days Frozen: 6 months
Reject criteria	Gross hemolysis • Grossly lipemic • Unseparated serum or plasma • Whole blood specimens

Reference range(s)

Reference Range(s)

Age	Male (umol/L)	Female (umol/L)
0-1 years	Not Established	Not Established
2-9 years	≤7.6	≤7.6
10-14 years	≤9.7	≤8.4
15-17 years	≤11.3	≤10.2
18-29 years	≤12.9	≤10.9
30-49 years	≤13.5	≤11.0
>49 years	≤15.2	≤13.4

LOINC® codes

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Service Area Information

Performing lab & setup schedule

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Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

*The CPT codes provided are based on AMA guidance and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

This material contains content from LOINC® (http://loinc.org). The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license.

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