D-dimer Test. Elevated D-dimer level. D-dimer Range in Pragnancy
D-dimer is a breakdown product of fibrin protein, which is present in the blood after the destruction of a blood clot.
The products are formed during the lysis of a blood clot under the influence of plasmin and some fibrinolytics. In a number of pathological conditions characterized by the activation of blood coagulation, a constant process of formation of a fibrin clot occurs in the body, and then its splitting.
A normal D-Dimer is considered less than 500μg/mL (0.50 mg/ml).
An elevated level of D-dimer is found in numerous conditions associated with activation of coagulation: disseminated intravascular coagulation syndrome, deep vein thrombosis, pulmonary thromboembolism, massive tissue damage or surgery, heart failure, infections, inflammation, and neoplastic conditions.
D-dimer test allows PE to be ruled out when clininical suspicion is low or moderate, but interpretation is complicated by the fact that d-dimer levels normally rise with age.
In a recent multicenter European study, investigators prospectively evaluated the accuracy of an age-adjusted d-dimer cutoff in 2898 patient with low or moderate clinical probability for PE (pulmonary embolism). A d-dimer result was considered negative if it was less than age × 10 for patient aged 50 and older while, for younger patient , the cutoff was fixed at 500 μg/mL.
Patient with a positive result underwent CTPA (CT pulmonary angiogram). All patients were followed for 3 months . Of 331 patients aged 50 and older with d-dimer levels between 500 μg/mL and their age-adjusted cutoff, only one (0.3%) was found to have PE during follow-up. The use of the age-adjusted cutoff resulted in a 12% absolute increase and a 41% relative increase in the proportion of negative d-dimer result .
D-dimer during pregnancy
In pregnant women, from early pregnancy, the level of D-dimer in the blood gradually rises. By the end of the gestation period, its values can be 3-4 times higher than the initial level.
Pregnant women:
1 trimester: <1000 ng / ml;
2nd trimester: <1800 ng / ml;
3rd trimester: <3000 ng / ml.
Algorithm for Pregnant Patient Suspected to Have Pulmonary Embolus:
Venous U/S Venous ultrasound
VTE Venous thromboembolism
CXR Chest X-ray
V/Q ventilation/perfusion lung scan
CTPA CT pulmonary angiogram
