Biochemistry and Formation

• Product of blood clot breakdown (fibrinolysis)
• Named for two cross-linked D fragments
• Forms when thrombin converts fibrinogen to fibrin
• Released into bloodstream during clot breakdown

Clinical Applications

• Essential for diagnosing thrombotic conditions
• Used in Venous Thromboembolism (VTE) diagnosis
• Helps assess Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE)
• Valuable in COVID-19 severity assessment

Measurement Methods

• ELISA: Gold standard with highest sensitivity
• Latex Agglutination Tests: Rapid but moderate sensitivity
• Immunoturbidimetric Assays: Automated with quick results
• Normal levels typically below 500 ng/mL FEU

Limitations and Confounding Factors

• False positives common in pregnancy, advanced age, and active malignancy
• Interpretation varies by laboratory
• Results affected by recent surgery, trauma, and underlying conditions
• Requires special consideration for specific patient groups

Future Directions

• Expanding role in COVID-19 management
• Growing applications in cancer monitoring
• Development of standardized testing methods
• Integration with artificial intelligence
• Improvements in point-of-care testing