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Lab Dept:
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Coagulation
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Test Name:
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PLASMINOGEN ACTIVATOR INHIBITOR
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General Information
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Lab Order Codes:
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PAI1
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Synonyms:
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Plasminogen Activator Inhibitor 1 Activity; PAI-1 Antigen
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CPT Codes:
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83520 – Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; quantitative, not otherwise specified
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Test Includes:
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Plasminogen Activator Inhibitor 1 antigen level reported in ng/mL.
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Logistics
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Test Indications:
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Identification of heredity elevation or deficiency of plasminogen activator inhibitor type 1. Determination of risk for veno-occlusive disease associated with bone marrow transplantation. Differential diagnosis of impaired fibrinolysis. Prognostic marker of occurrence or recurrence of thrombosis.
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Lab Testing Section:
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Coagulation - Sendouts
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Referred to:
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Mayo Medical Laboratories (MML: 86083)
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Phone Numbers:
Minneapolis:
Saint Paul:
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612-813-6280
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651-220-6550
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Test Availability:
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Daily, 24 hours
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Turnaround Time:
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Testing performed once weekly on Thursdays.
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Special Instructions:
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See Patient Preparation. PAI-1 has a circadian rhythm, high in the early morning and falling in the afternoon and evening. This change should be considered when planning PAI-1 plasma studies. The PAI-1 antigen reference range is based on fasting morning samples in adults.
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Specimen
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Specimen Type:
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Whole blood
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Container:
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Light Blue (Buffered Na Citrate 3.2 %) top tube
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Draw Volume:
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2.7 mL blood in a 3 mL tube (Minimum:1.8 mL in a 2 mL tube)
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Processed Volume:
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1 mL (Minimum: 0.3 mL) plasma
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Collection:
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Routine venipuncture. Do Not use the first 2 mL of blood collected.
If the patient’s hematocrit is >55%, contact laboratory to obtain a special tube. Mix thoroughly by gentle inversion.
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Special Processing:
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Lab Staff:
PAI-1 is unstable and must be processed and frozen within 3 hours of specimen collection.
Double spin required: Centrifuge specimen (1500 g for 10 min), aliquot plasma to a plastic tube. Spin plasma again (1500 g for 10 min). Remove plasma to another plastic vial and freeze specimen immediately at < or = -40 degrees C. Forward promptly.
Note: Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results. Each coagulation assay requested, must have its own vial.
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Patient Preparation:
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It is recommended, but not required that specimen should be early morning fasting specimen (before 10 am).
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Sample Rejection:
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Improper tube; clotted samples; overfilled tubes; underfilled tubes; mislabeled or unlabeled specimens
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Interpretive
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Reference Range:
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3 - 72 ng/mL
Note: Based on fasting and early morning collections in adults.
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Critical Values:
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N/A
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Limitations:
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The plasminogen activator inhibitor type 1 (PAI-1) level shows a diurnal variation with the highest levels occurring in the morning. The PAI-1 level increases during pregnancy and decreases rapidly after delivery. The extremely rare presence of anti-mouse antibodies in certain patients may lead to anomalous results. Inappropriate specimen collection and processing may lead to platelet activation and release of platelet PAI-1. Consequently, care must be taken to remove all platelets and minimize platelet activation during specimen collection and processing.
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Methodology:
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Enzyme-Linked Immunosorbent Assay (ELISA)
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References:
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Mayo Medical Laboratories April 2012
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Harmening DH (1997) Clinical Hematology and Fundamentals of Hemostasis
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Updates:
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2/1/2008: Method change, units change. Now performed at Fairview, previously forward to SE Blood Center of Wisconsin.
5/24/2010: Tubing of patient specimens is no longer prohibited.
2/16/2012: Fairview now forwards test to Blood Center of Wisconsin.
4/12/2012: Test moved from Fairview forward to Blood Center of Wisconsin to Mayo Medical Laboratories.
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