D-dimer - what is it? At what diseases it is necessary to pass such analysis?

Some patients, especially when it comes to pregnant women, prescribe an analysis for D-dimer. What it is? Why do we need these tests? What diseases can be diagnosed with this technique?

D-dimer - what is it?

The mechanism of folding the blood is quite complicated. But if we sum up, it looks like this. Under the influence of thrombin, fibrin is formed, which subsequently is susceptible to plasmin. This enzyme cleaves the molecules of fibrin and fibrinogen into smaller fragments.

Sometimes during the process of fibrinolysis plasmin is not able to completely break down the fibrous fiber, as a result of which D-dimers are formed - rather large structures. Thus, the analysis of the presence of D-dimers gives doctors the opportunity to evaluate the processes of blood coagulability and to detect a tendency to thrombosis.

How to prepare for blood donation?

Fortunately, modern medicine has developed tests that help determine whether D-Dimer is present in the blood plasma. What are these tests? The level of this substance can be determined using methods of immunological examination of blood plasma.

Blood sampling is carried out in the morning, always on an empty stomach (you can drink only pure water). You can not smoke before giving blood. Also, do not subject the body to heavy physical exertion. One day before the procedure, it is necessary to exclude fatty foods from the diet, since this can affect the blood test.

D-dimer is an important marker, as it helps to trace the mechanism of formation and disintegration of fibrinogen. This study is used for suspected thrombosis and DIC.

Indicators of "D-dimer" are increased: what does this mean?

Normally, the level of the dimer in the blood should not exceed 500 ng / ml. In most cases, an increase in this indicator indicates a thrombus. In particular, the analysis is often used to diagnose deep vein thrombosis or pulmonary embolism.

On the other hand, there are other reasons that can lead to such a violation. Risk factors include older age, since almost every patient over 80 years old D-dimer is elevated. In addition, a similar pattern is observed in pregnant women.

In some cases, an increase in the level of this substance is associated with diseases, for example, the presence of a tumor or infection. In addition, the same result is observed with some liver lesions, with active inflammatory processes disseminated by intravascular coagulation .

The risk factors include extensive hematomas, myocardial infarction, ischemic heart disease. Sometimes such results can be obtained against thrombolytic therapy.

Causes of false negative results

Under the influence of some factors, even with thrombosis, you can get the result, where the norm is D-dimer. What are these factors that affect the accuracy of the studies? First of all, it should be noted that D-dimer is a substance that decomposes relatively fast - six hours after the appearance in the blood it is already impossible to detect its traces.

In some cases, false negative results appear with too small clots. In any case, several diagnostic procedures are carried out for the patient to determine the exact diagnosis.