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Homocysteine

Test Code

31789

CPT Code(s)

83090

Preferred Specimen(s)

1 mL serum

Minimum Volume

0.5 mL

Alternative Specimen(s)

Plasma collected in: EDTA (lavender-top), or sodium heparin (green-top) tube

Collection Instructions

Red-top tubes: Place the specimen in a refrigerator or ice bath for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation has taken place.

Barrier gel separator tubes:
Place the specimen in a refrigerator for 30 minutes after collection. Centrifuge the specimen as soon as possible after complete clot formation has taken place. Do not place barrier tubes in an ice bath as freezing may prevent the barrier gel from adequately separating serum from cells.

EDTA or heparin tubes:
Place the specimen in a refrigerator or ice bath until the specimen can be centrifuged. Centrifuge the specimen as soon as possible and transfer the plasma to a plastic screw-capped vial.

(Royal blue-top) serum tube and (royal blue-top) sodium heparin tubes are acceptable containers. Instruction for collecting blood in (royal blue-top) serum tubes is similar to red-top or SS tubes or sodium heparin tubes.

Specimen Container

Plastic screw-cap vial

Transport Temperature

Refrigerated (cold packs)

Specimen Stability

Room temperature: 4 days
Refrigerated: 14 days
Frozen: 6 months

Reject Criteria

Gross hemolysis • Unseparated serum or plasma • Whole blood specimens • Grossly lipemic

Methodology

Enzymatic

Performing Laboratory

Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153

Setup Schedule

Set up: Mon-Fri night; Report available: Next day

Reference Range(s)

Male <11.4 umol/L
Female <10.4 umol/L

Clinical Significance

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).

LOINC®' Code(s)

The Result and LOINC information listed below should not be used for electronic interface maintenance with Quest Diagnostics. Please contact the Quest Diagnostics Connectivity Help Desk for more information at 800-697-9302.

NOTE: The codes listed in the table below are not orderable Test Codes.

Result
Code
Result NameLOINC CodeComponent Name
31789Homocysteine13965-9Homocysteine

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 guidelines 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.

LOINC assignment is based on a combination of test attributes, including the method used by the performing laboratory. For tests not performed by Quest Diagnostics, codes are assigned by the performing laboratory.

* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.