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HelpTest Code A2PI Alpha-2 Plasmin Inhibitor, Plasma
Specimen Required
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. For complete instructions, see Coagulation Guidelines for Specimen Handling and Processing.
2. Centrifuge, transfer all plasma into a plastic vial, and centrifuge plasma again.
3. Aliquot plasma into a plastic vial leaving 0.25 mL in the bottom of centrifuged vial.
4. Freeze plasma immediately (no longer than 4 hours after collection) at -20° C or, ideally, -40° C or below.
Additional Information:
1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results.
2. Each coagulation assay requested should have its own vial.
Secondary ID
602169Useful For
Diagnosing congenital alpha-2 plasmin inhibitor deficiencies (rare)
Providing a complete assessment of disseminated intravascular coagulation, intravascular coagulation and fibrinolysis, or hyperfibrinolysis (primary fibrinolysis), when measured in conjunction with fibrinogen, fibrin D-dimer, fibrin degradation products, soluble fibrin monomer complex, and plasminogen
Evaluating liver disease
Evaluating the effects of fibrinolytic or antifibrinolytic therapy
Special Instructions
Method Name
Chromogenic
Reporting Name
Alpha-2 Plasmin Inhibitor, PSpecimen Type
Plasma Na CitSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Clinical Information
Alpha-2 plasmin inhibitor (antiplasmin) is synthesized in the liver with a biological half-life of approximately 3 days. It inactivates plasmin, the primary fibrinolytic enzyme responsible for remodeling the fibrin thrombus, and binds fibrin together with factor XIIIa making the clot more difficult to lyse. Absence of alpha-2 plasmin inhibitor results in uncontrolled plasmin-mediated breakdown of the fibrin clot and is associated with increased risk of bleeding.
Reference Values
Adults: 80-140%
Normal, full-term, and premature infants may have mildly decreased levels (≥50%) that reach adult levels within 90 days postnatal.*
*See Pediatric Hemostasis References section in Coagulation Guidelines for Specimen Handling and Processing.
Interpretation
Patients with congenital homozygous deficiency (with levels of <10%) are clinically affected (bleeding). Heterozygous individuals having levels of 30% to 60% of mean normal activity are usually asymptomatic.
Lower than normal levels may be suggestive of consumption due to activation of plasminogen and its inhibition by alpha-2 plasmin inhibitor.
The clinical significance of high levels of alpha-2 plasmin inhibitor is unknown.
Cautions
Alpha-2 plasmin inhibitor results are potentially affected by the following:
-Heparin, unfractionated or low-molecular-weight >4 U/mL
-Alpha-2-macroglobulin >7 mg/mL; potentially leading to a falsely increased result
-Hemoglobin >200 mg/dL
-Bilirubin >20 mg/dL
-Triglycerides >1000 mg/dL
Clinical Reference
1. Lijnen HR, Collen D. Congenital and acquired deficiencies of components of the fibrinolytic system and their relation to bleeding or thrombosis. Blood Coagul Fibrinolysis. 1989;3(2):67-77. doi:10.1016/0268-9499(89)90034-9
2. Francis RB Jr. Clinical disorders of fibrinolysis: A critical review. Blut. 1989;59(1):1-14
3. Aoki N. Hemostasis associated with abnormalities of fibrinolysis. Blood Rev. 1989;3(1):11-17
4. Singh S, Saleem S, Reed GL. Alpha2-antiplasmin: The devil you don't know in cerebrovascular and cardiovascular disease. Front Cardiovasc Med. 2020;7:608899
Method Description
This assay is performed using the HemosIL Plasmin Inhibitor Kit on the Instrumentation Laboratory ACL TOP Family. Patient plasma, containing alpha-2 plasmin inhibitor, is mixed with reagent containing excess plasmin. Plasmin activity in the reagent is rapidly inhibited by alpha-2 plasmin inhibitor. Residual plasmin activity is then measured using an amidolytic activity assay, in which residual plasmin lyses a synthetic chromogenic substrate and subsequently releases para-nitroanline (detected at 405 nm) to a level that is inversely proportional to the amount of alpha-2 plasmin inhibitor in the sample.(Teger-Nilsson AC, Friberger P, Gyzander E. Determination of a new rapid plasmin inhibitor in human blood by means of a plasmin specific tripeptide substrate. Scand J Clin Lab Invest. 1977;37(5):403-409; package insert: HemosIL Plasmin Inhibitor. Instrumentation Laboratory; 11/2019)
Day(s) Performed
Monday through Friday
Report Available
3 to 7 daysSpecimen Retention Time
7 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
85410
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| A2PI | Alpha-2 Plasmin Inhibitor, P | 27810-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| A2PI | Alpha-2 Plasmin Inhibitor, P | 27810-1 |
Forms
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.