- What is serological diagnosis?
- What is a non-treponemal method?
- Disadvantages of the
- method How is the analysis done?
- Analysis of
- When is the analysis done?
- Who is appointed?
- Indications for screening
What is serological diagnosis?
This is an indirect method of detecting a pathogenic microorganism. When serological examination of blood reveals not the causative agent of the disease, but antibodies, which are produced by immune cells when it is introduced, that is, determine its presence by the reaction of the body.
What is a non-treponemal method?
As it is known, syphilis causes pale treponema, related to spirochaetes( spiral-shaped bacteria).After its introduction in the body, antibodies( immunoglobulins IgG and IgM) begin to be produced to lipoproteins and phospholipids, which are released as a result of cell damage by the spirochete, and to the lipids of the membrane of the pathogen itself. Antibodies to lipids appear in the blood about a month after infection. With this test in primary syphilis, they are detected in the blood in 90% of cases 6 weeks after infection. In secondary syphilis, a positive result is recorded in almost 100% of cases.
The causative agent of syphilis is the spiral bacterium pale treponema
Disadvantages of the
method The main disadvantage of EMF is the low specificity and the possibility of false positive results. The fact is that anti-lipid antibodies can be produced not only with syphilis, but also for other reasons. Among them:
- chronic and acute diseases: tuberculosis, hepatitis, systemic lupus erythematosus, tumors, inflammatory heart diseases, blood diseases, diabetes, scleroderma, dermatosis and others;
- physiological conditions: menstruation, pregnancy;
- anesthesia, taking certain medications;
- addiction, alcoholism;
- eating fatty foods and alcohol on the eve of blood donation.
In addition, such testing is useless in the late stage of syphilis due to lack of sensitivity.
How is the analysis done?
Venous blood is usually used for research. It is taken in the morning on an empty stomach, that is, the last meal should take place no later than 8 hours before the procedure. On the eve it is not recommended to drink alcohol and eat fatty foods.
Two or three drops of the patient's blood serum are mixed with the cardiolipin antigen in the glass plate and a reaction that lasts for 30 minutes is monitored for syphilis. The conclusion is made by the amount of sediment and the size of the formed flakes. The intensity of the reaction is assessed on a scale of one to four( +, ++, +++, ++++).
If the reaction is positive, confirmation of the result is required with treponemal tests.
The result of EMF can be either negative or positive. The more pluses, the more serious the defeat:
- + and ++ - weakly positive reaction( with one plus the result is considered doubtful);
- +++ - positive;
- ++++ - sharply positive.
As a result, studies indicate antibody titers. If the analysis is carried out to monitor the treatment, then it is determined by titles if a recovery has occurred. As a rule, after treatment the patient is under observation for a year. During this time passes the test several times. On the effectiveness of treatment, they say, if the titles for the year fell four times or more. If there are no IgM immunoglobulins in the blood, then there is no renewal of the infection. Immunoglobulins IgG can be present in the blood for a long time after treatment, sometimes even all life.
Analysis result may be negative or positive
When is the analysis performed?
Non-treponemal tests are needed in the following cases:
- during medical examinations of healthy people;
- as a primary analysis in case of suspected syphilis;
- before conception and during gestation;
- for confirming the latent form of the disease;
- for donor verification;
- for assessing the effectiveness of syphilis treatment.
To whom appoint?
Referral to EMF is given to the following categories of persons:
- people with symptoms of the disease;
- persons who have been in contact with sick syphilis;
- people who have infected sexual partners;
- children born to sick mothers;
- people with other sexually transmitted infections.
Indications for screening
Some population groups are regularly subjected to preventive medical examinations, including EMF.These include:
- blood donors;
- pregnant women;
- military personnel;
- patients admitted to hospital;
- patients who are preparing for surgery;
- physicians, employees of children's institutions and public catering establishments;
- are in prison.
EMF is a convenient and fast way of preliminary diagnosis of syphilis in the early stages. The result can not be considered accurate, which means that it is impossible to make a diagnosis until a complete examination using other methods is carried out.