Tissue Plasminogen Activator (tPA) Antigen
Use
This test is used for the quantitative determination of human tissue plasminogen activator antigen in plasma by enzyme immunoassay. Tissue plasminogen activator serves to activate plasminogen to plasmin, which degrades fibrin to soluble fibrin degradation products. Elevated tPA levels are strongly associated with preclinical atherosclerosis and have been shown to indicate risk of future myocardial infarction. Elevated tPA levels are also associated with an increased risk of stroke, particularly in individuals within the top 5% of tPA values.
Special Instructions
Tissue plasminogen activator is stored in endothelial cells and is released following exercise, venous occlusion, and injection of substances like epinephrine. It is inhibited by plasminogen activator inhibitor-1 (PAI-1).
Limitations
The tPA levels may be increased with a difficult or traumatic venipuncture or if the tourniquet is left on too tight or too long during specimen collection. Elevated results may occur due to tPA release during strenuous exercise or specimen procurement.
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 5971-7
- 5971-7
Result Turnaround Time
4-8 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
Not provided
Container
Blue-top (sodium citrate) tube
Collection Instructions
Citrated plasma samples should be collected by double centrifugation. Blood should be collected in a blue top tube containing 3.2% buffered sodium citrate. The sample should be mixed immediately by gentle inversion at least six times. Centrifuge for 10 minutes and carefully remove 2/3 of the plasma. Deliver to a plastic transfer tube, cap, and recentrifuge for 10 minutes. Transfer the plasma into a Labcorp plastic lavender top tube with cap. The specimen should be frozen immediately.
Storage Instructions
Freeze; six freeze/thaw cycles are acceptable.
Causes for Rejection
Hemolysis; specimen clotted with fibrin; specimen contaminated with heparin.