D-Dimer (Lab Test)

WHAT IS IT?

A D-dimer test is an assay that detects the amount of D-dimer present within a patient’s blood. D-diemr is a degradation product of cross-linked fibrin. This will be present in a patient if there is a clot within their body that is being broken down.

Plasminogen will cleave cross linked fibrin to give about products such as D-dimer (source)
Plasmin will cleave cross linked fibrin to give about degradation products such as D-dimer (source)
WHY DO WE DO IT?

This test has utility in helping diagnose conditions that involve the formation of thrombi/emboli/clots such as deep vein thrombosis/pulmonary embolism.

HOW IS IT DONE?

There are multiple types of D-dimer assays that can be performed (both qualitative and quantitative). The quantitative methods use ELISA assays to calculate the concentration of D-dimer within the patient’s serum.

WHAT ARE THE REFERENCE VALUES?

The conventional cutoff value for a “normal” D-dimer result is <500 ng/mL

WHAT DOES IT TELL US?

This test is sensitive in that it is effective in detecting the present of a clot (or multiple clots) within the blood.

WHAT CAN’T IT TELL US?

The test is not specific. A positive D-dimer only means that cross linked fibrin is being degraded somewhere withthin the patients body, and will not establish WHERE the clot/clots are .

 

 

Page Updated: 05.30.2016