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HelpTest Code PSGN Plasminogen Activity, Plasma
Reporting Name
Plasminogen Activity, PUseful For
Evaluating patients with ligneous conjunctivitis (strong association with homozygous plasminogen deficiency)
Evaluating fibrinolysis, in combination with other components of the fibrinolytic system (fibrinogen, tissue plasminogen-activator-inhibitor, and d-dimers)
Method Name
Chromogenic
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Plasma Na CitOrdering Guidance
Coagulation testing is highly complex, often requiring the performance of multiple assays and correlation with clinical information. For that reason, we suggest ordering AATHR / Thrombophilia Profile, Plasma and Whole Blood.
Necessary Information
If priority specimen, mark request form, give reason, and request a call-back.
Specimen Required
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (3.2% sodium citrate)
Submission Container/Tube: Plastic vial (polypropylene preferred)
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 separate 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 at -40° C or below.
Additional Information:
1. A 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.
Specimen 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 |
Special Instructions
Reference Values
75-140%
Day(s) Performed
Monday through Friday
CPT Code Information
85420
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PSGN | Plasminogen Activity, P | 28660-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| PSGN | Plasminogen Activity, P | 28660-9 |
Clinical Information
During the formation of a hemostatic (fibrin) plug, biochemical mechanisms are initiated to limit the extent of the hemostatic process at the site of injury and maintain vascular patency. This process of fibrinolysis is defined as the plasmin-mediated degradation of fibrin. Plasmin limits the extent of the hemostatic process at the site of vessel injury.
Plasmin is generated from its precursor, plasminogen, by plasminogen activators (ie, tissue plasminogen-activator: tPa; urokinase-type plasminogen activator: uPa). Plasminogen is a single-chain glycoprotein that is synthesized in the liver and has a biologic half-life of approximately 2 days.(1) Deficiency of plasminogen may be inherited or acquired. Persons with congenital plasminogen deficiency are at an increased risk for development of an ocular condition called ligneous conjunctivitis. Congenital deficiency of plasminogen is autosomally transmitted and rare in the general population, with a prevalence of approximately 0.4%.(2)
Based on the results of functional and immunologic (antigenic) assays, 2 types of plasminogen deficiency have been identified:
-Quantitative deficiency (type I)-defined by a corresponding decrease in both plasminogen activity and antigen level
-Functional deficiency (type II)-caused by a normally synthesized but dysfunctional plasminogen
This plasminogen activity assay will identify both types of deficiency.
Acquired causes of plasminogen deficiency include consumption such as with thrombolytic therapy (urokinase, tPa) or disseminated intravascular coagulation/intravascular coagulation and fibrinolysis (DIC/ICF), or decreased synthesis (liver disease).(1)
Interpretation
Plasminogen activity below 75% may represent a congenital deficiency state, if acquired deficiency can be excluded.
Hereditary abnormalities of plasminogen (deficiency or dysfunction) are very uncommon.
Acquired causes of plasminogen deficiency are much more common and may be the result of consumption due to thrombolytic therapy or intravascular coagulation and fibrinolysis or decreased synthesis (ie, liver disease).
Plasminogen levels are low at birth (approximately 50% of adult normal level) and reach adult levels at 6 months of age.
Cautions
Proper preparation of the blood (plasma) specimen is extremely important to help ensure accuracy of results and interpretation.
Plasminogen results are potentially affected by:
-Elevated levels of fibrinogen
-Heparin (unfractionated or low-molecular-weight) >4 U/mL
-Fibrin degradation products (FDP) >30 mg/dL
-Hemoglobin >200 mg/dL
-Bilirubin >20 mg/dL
-Triglycerides >1000 mg/dL
Method Description
This assay is performed using the HemosIL Plasminogen Kit on the ACL TOP instrument. The method is an automated chromogenic assay in which an excess of streptokinase in the presence of fibrinogen is added to sample plasma containing plasminogen. A plasminogen-streptokinase complex is formed. The complex catalyzes the splitting of p-nitroaniline (pNA) from the substrate S-2403 pyroGlu-Phe-Lys-pNAHCl. Under these conditions the enzymatic activity of the complex is not inhibited by plasma inhibitors. The rate at which the pNA is released is measured kinetically at 405 nm and is directly proportional to the plasminogen level in the test specimen. The concentration of plasminogen is calculated from a standard curve prepared from reference plasma dilutions.(Package insert: HemosIL Plasminogen. Instrumentation Laboratory Company; 03/2019)