CME Information

Editorial Board

Lessons by Volume

Thrombophilia: How To Test? How To Manage?

By Julie Hambleton, MD

Print This | TOC | Previous | Next

**Table 3—***Laboratory Characteristics and Common Pitfalls*
AT Levels
Functional assay widely available Levels decrease with liver disease, DIC, heparin therapy (acutely), and nephrotic syndrome Levels may increase with warfarin therapy
PC Levels
Functional assay widely available Levels decrease with liver disease, DIC, ARDS, warfarin
PS Levels
Enzyme-linked immunosorbent assay–based test used to measure both total and free PS is currently the most reliable assay Functional assay less reliable Levels decrease with liver disease, DIC, warfarin Excessive binding of PS to C4b-BP may occur in states of acute or chronic inflammation (eg, systemic lupus erythematosus, nephrosis, pregnancy)
Factor V Leiden
Polymerase chain reaction–based assay is preferred (loss of an enzyme restriction site) Activated protein C (APC) ratio: activated partial thromboplastin time (aPTT) [+ APC] / aPTT [– APC] Normalize to reference plasma Affected individual's normalized ratio < 0.84 Affected by anticoagulation
Hyperhomocysteinemia
Plasma homocysteine levels: baseline fasting state ± postmethionine load DNA-based testing for MTHFR polymorphism
Prothrombin 20210
DNA-based test for polymorphism Prothrombin level (factor II activity) insensitive

Print This | TOC | Previous | Next




3300 Dundee Road • Northbrook, Illinois 60062-2348 • (847) 498-1400 • (800) 343-2227 Copyright ©1999-2008 American College of Chest Physicians. All Rights Reserved. ACCP Privacy Policy \| ACCP Web Site Terms of Use