19Feb

Blood test for Wasserman reaction( RW)

Most screening methods are associated with various blood tests. They are designed for a massive survey of people to identify dangerous diseases. The technique of their implementation( analysis from a vein or a finger) and the price of reagents is so simple and accessible that every public medical institution examines its patients for free. But recently there have been conflicting data regarding the analysis of blood on the RW.According to them, this research is not always as informative as it was thought before.

What is this analysis of

? The essence of the RW blood test is to determine the specific markers of syphilis. This venereal disease, like any infectious process, causes the appearance of antibodies that provide an immune response and protect the body from the progression of the disease. The analysis in which these specific antibodies are determined is called the Wasserman reaction, or the blood on the RW.

How it is done and what blood is needed for the analysis of

Any blood can be used as a material for the analysis, both from the vein and from the finger. The specificity and reliability of the analysis carried out depends on many factors. It is important to consider that this is a nonspecific analysis, which has a lot of false positive and false negative results. Therefore, it can not be relied on with complete certainty in any case. This is due to the fact that blood from the finger can be examined only by the micro-precipitation reaction

. It allows us to quickly determine the presence of antibodies in the body. But their specificity can not be determined. Such antibodies can be any proteins that are formed in large numbers in any infectious processes, allergic reactions of immediate and delayed type. This means that a true disease is capable of masking under a false positive RW and mistakenly perceived for syphilis. On the other hand, venous blood from the finger is not able to detect small concentrations of specific antibodies to the causative agent of syphilis in the initial stages of the disease or in its slow flow. This causes a false negative result.

It's important to remember! The diagnostic significance of a finger blood test on RW is so low that it makes this method inappropriate for medical practice. More reliable results can be obtained only in the study of venous blood. In contrast to the analysis of the finger, which makes it possible to investigate only a small amount of whole capillary blood, a plasma can be obtained from the venous blood, which contains all the antibodies circulating in the body!

Do not forget about the correctness of the study. To give blood is best in the morning or at least on an empty stomach. The day before, strong physical and psychoemotional loads are excluded. It is desirable to minimize the administration of drugs that affect the activity of the immune response and cause an allergic reaction.

In what cases is the

appointed? Expediency in carrying out a blood test for RW has two purposes.

Diagnostic

Assumes examination of persons at risk for developing syphilis or those who must necessarily be excluded from this disease:

  • In the presence of complaints typical of sexually transmitted diseases or unprotected casual sex;
  • In the presence of any manifestations of syphilis;
  • When pregnant. All pregnant women are examined on the RV when being registered in a female consultation and again during pregnancy;
  • All patients who are hospitalized in medical institutions, especially surgical hospitals;
  • All persons undergoing routine medical examinations;
  • Medical workers;
  • in contact with sick syphilis;
  • Drug addicts and patients with HIV;
  • Persons with prolonged fever and doubts about the reliability of the diagnosis.
Pale treponema under the microscope
The analysis of blood on RW allows to detect antibodies to pale treponema - the causative agent of syphilis

The therapeutic purpose of

Assumes the conduct of RW in the dynamics of all patients with syphilis. This allows you to identify secondary and tertiary forms of syphilis, which are disguised as a mask of any internal diseases. In patients undergoing treatment with the established diagnosis of syphilis, due to RW, the dynamics of the course of the process, its activity and the effectiveness of the medicines used are determined.

How to correctly assess the results of

The interpretation of the results of a blood test for RW can be represented in several ways.

RW negative( norm)

Also read: Pathological microorganisms in the bloodstream
How does the infection of blood appear?

Says that no antibodies to syphilis are found in the blood of the patient. This means that he has nothing to do with this disease.

RW positive

There are 4 degrees of positive reaction, which are indicated by the corresponding number of + signs. The more of them, the greater the likelihood of contracting syphilis. All persons with positive RW are subject to re-examination. In patients who have recovered from syphilis, a positive RV in the form of 4 pluses can be lifelong.

RW False positive

May be with:

  • Active inflammatory process in lung tissue, including tuberculosis;
  • Systemic diseases of connective tissue;
  • Arthritis of various origin;
  • After vaccination or infectious diseases;
  • In pregnant women;
  • Malignant tumors;
  • Diabetes mellitus;
  • Viral hepatitis and HIV infection.

If there is any doubt about the reliability of the results of the performed blood test for RW, it can be performed using more modern serological diagnostic methods( take blood from the vein for RIF, ELISA), which have higher specificity and reliability.

It's important to remember! Negative RW does not give a 100% guarantee of the absence of syphilis. This is due to the presence during this disease, the so-called, seronegative window. This means that from the moment of infection with syphilis, some time must elapse for the formation of the corresponding antibodies. If the blood from the vein, and even more so from the finger, is withdrawn in this time interval, a false negative result will be obtained!