Methodology
Tandem Mass Spectrometry
Synonyms
Homocystine
Specimen Type
Serum or Plasma
Performing Lab
UCSD Biochemical Genetics
Epic ID
LAB00798
Lab Test Days
Monday-Friday
Standard TAT
12-16 Days
Collection Information
Specimen Required
2 mL Blood
Container Type
Light Green (Lithium Heparin PST)
Collection Instructions
Urine is NOT acceptable. See Homocystein, Urine to Quest forwards to Mayo. Plasma collected in sodium heparin (green-top) or EDTA (lavender-top) tube is also acceptable. Serum collected in a red-top or serum separator tube (SST) is also acceptable but only as an alternative if needed.
Processing Information - Lab Use Only
Transport Temperature
Frozen-Only
Test Volume Required
1 mL Plasma
Minimum Test Volume
0.5 mL Plasma
Processing Instructions
Centrifuge, separate serum or plasma freeze promptly. Complete UCSD Biochemical Genetics requisition and submit with specimen frozen.
Included Tests
Where older methods only measured free homocystine, this method detects total (free and protein-bound, reduced homocystein and oxidized homocystine).
Comments
Elevation of homocysteine is diagnostic for homocystinuria, and has been associated with vaso-occclusive and thrombotic disease. Noted that this method does not detect homocystine in healthy subjects, so normal range is not directly comparable to that of older methods.
CPT Codes
83090
Revised
01-18-15
Initials
SL