Test Catalog

Test ID: HCYSP    
Homocysteine, Total, Plasma

Specimen Type Describes the specimen type validated for testing

Plasma EDTA

Necessary Information

1. Patient's age and sex are required.

2. Biochemical Genetics Patient Information (T602) is recommended, but not required, for suspected cases of inherited disorders of methionine metabolism.

Specimen Required Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Collection Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Green top (sodium or lithium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Immediately place specimen on wet ice.

2. Centrifuge and aliquot plasma into plastic vial within 4 hours of collection.

3. If blood cannot be placed on wet ice immediately, centrifuge and aliquot plasma into plastic vial within 1 hour of collection.

4. A refrigerated centrifuge is not required if the above time restrictions are met.


1. Biochemical Genetics Patient Information (T602) in Special Instructions

2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.

Specimen Minimum Volume Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.10 mL

Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen TypeTemperatureTimeSpecial Container
Plasma EDTARefrigerated (preferred)28 days
 Frozen 309 days
 Ambient 28 days