Synonyms: ASL-O, ASLO, Antistreptolysin-O, ASO.

Streptococci are bacteria that produce special enzymes when they enter the human body. One of them is streptolysin-O, a protein that destroys red blood cells. It is on him that the immune system begins to produce anti-streptolysin-O (ASL-O), which can protect the body from the action of both the streptococci themselves and their toxins.

An examination for antistreptolysin-O allows timely detection of diseases provoked by streptococci and their metabolic products. However, this analysis has the greatest diagnostic value for detecting acute rheumatic fever, since it is one of the laboratory criteria for rheumatism.

General information

Streptococci are divided into groups according to the type of exposure and their characteristics. Group A beta-hemolytic streptococcus is the most dangerous, as it is the causative agent of serious pathologies:

• scarlet fever (highly contagious (contagious) infectious disease);
• glomerulonephritis (damage to the glomeruli of the kidneys);
• tonsillitis and tonsillitis (inflammation of the tonsils);
• erysipelas (skin infection);
• rheumatic fever - rheumatism (inflammation of the connective tissue);
• osteomyelitis (purulent-necrotic process in soft tissues, bone and bone marrow);
• bacterial endocarditis (damage to the inner lining of the heart muscle);
• pyoderma (purulent skin lesions), etc.

Different types of toxins released by bacteria cause different pathological symptoms or syndromes. One of these components is the protein streptolysin, which damages red blood cells - erythrocytes. In response to the release of streptolysin, the body secretes antibodies (Anti-streptolysin-O). Their concentration begins to rise 1-5 months after infection with streptococcal infection. The ASL-O indicator returns to normal only after six months or a year.

Indications

Deciphering the analysis for ASL-O can be carried out by an immunologist, an infectious disease specialist, as well as any general practitioner (therapist, pediatrician, family doctor, etc.).

Indications for analysis may be the following reasons:

• Recurrent diseases of the heart, kidneys, joints and nervous system (mainly in children);
• Diagnosis of rheumatism - an acute form of rheumatic fever;
• Monitoring the effectiveness of antistreptococcal therapy;
• Monitoring the treatment of purulent-inflammatory pathologies;
• Prolonged fever in a patient without established causes;
• Diagnosis of chronic diseases.

Important! Diseases caused by group A streptococcus often give serious complications to the internal organs (heart, liver, kidneys), joints, bone and nervous system. And since the concentration of ASL-O increases only a few weeks after infection with a streptococcal infection, this study only reveals the relationship between residual symptoms and bacterial activity in the body. Thus, analysis for ASL-O makes it possible to predict and prevent the development of severe complications.

Norms of antistreptolysin-O

Note: The peak concentration of ASL-O is reached not earlier than 1-1.5 months after the start of their production. It should also be borne in mind that antibodies remain in the patient's blood for several months.

Influencing factors

• A false-positive result is possible in healthy people who themselves are a carrier of group A streptococcus.
• False-positive results are given by tests performed on patients with liver disease.
• A false negative result can be obtained by taking antibiotics and anti-inflammatory drugs (Coldrex, ibuprofen, aspirin, etc.), steroids and corticosteroids, as well as hormones.
• A false-negative result is possible at the earliest stages of streptococcal infection (up to the moment when the maximum concentration of ASL-O is reached).

With local damage to the skin by streptococci, a high level of antibodies is determined only in 1/4 of all cases. Additionally, a test for antibodies to deoxyribonuclease B (anti-DNase B) is prescribed.

Raising ASL-O

An increase in the concentration of antistriptolysin-O is observed in the following diseases:

• reactive arthritis;

On a note: determination of the ASL-O index is necessary for the diagnosis of streptococcal infection during remission. However, the analysis is not informative enough, since an increase in the level of ASL-O antibodies in patients is possible only in 75% of cases. Therefore, diagnosis in the presence of certain symptoms characteristic of streptococcal diseases is necessarily supplemented by other laboratory tests.

Exceeding the concentration of ASL-O by 3-4 times may indicate a recent illness, the causative agent of which was streptococcus.

Important! A high concentration of antibodies in pregnant women does not affect the formation and development of the fetus, the course of pregnancy and the general well-being of the expectant mother.

Low antistreptolysin-O

A negative test result (low or no antibodies) rules out streptococcal infection. To confirm the result, it is advisable to conduct a second test after 2 weeks. If the disease was previously and in the future any of its complications are possible, then the level of antistreptolysin-O will rapidly increase.

Training

The biomaterial for the study is venous blood, which is taken from the cubital vein according to the standard venipuncture algorithm.

• Manipulation time - morning hours (from 8.00 to 11.00).
• A prerequisite is that blood is given strictly on an empty stomach. The use of clean drinking water without gas is allowed.

• 30-40 minutes before the manipulation, exclude physical and emotional stress;
• for half an hour - do not smoke and do not use nicotine-containing products (tobacco, chewing gum, spray, patch, etc.).

There are no special dietary requirements for this analysis.

Other rheumatology screening tests

Immunological blood tests are carried out to identify pathological conditions in the body, most often caused by systemic diseases. A blood test for ASO (antistreptolysin O) refers to rheumatic tests, which are a complex aimed at diagnosing inflammatory processes in the body, its severity and lesions.

Until now, it has not been precisely established under the influence of what factors the body begins to “fight” with itself: the developed ones destroy cells that the body mistakenly perceives as pathogens. Unfortunately, autoimmune diseases are one of the most common, they affect about 7% of the world's population, most of the patients are women.

Symptoms

The most common symptoms of autoimmune diseases include general malaise, various kinds of feverish conditions, joint and muscle pain, weight loss, skin rash, and sometimes baldness can be a symptom of an autoaggressive disease.

Blood test for ASO, what is it? This is antistreptolysin O, the patient for the presence and level of antibodies to beta-hemolytic streptococcus in the body.

Diagnostics

A blood test for ASO is carried out in combination with the study of markers of immunological disorders. Rheumoprobes are prescribed if the patient has autoimmune reactive arthritis, multiple sclerosis, autoimmune prostatitis, rheumatoid arthritis. This blood test is also prescribed for those who are often prone to diseases caused by streptococcus activity: scarlet fever, tonsillitis, including in acute form, tonsillitis,.

For the diagnosis of a disease, it is important to assess not only the presence or confirm the absence of antistreptolysin O in the blood, but also to evaluate quantitative indicators, which in some cases makes it possible to distinguish closely related diseases.

So, for example, if the protein content is low, then this indicates the presence of rheumatoid arthritis, and if, then this is most likely rheumatism.

An increase in the titer of antibodies in the blood, characterized by a short duration, may indicate the presence of infectious diseases. Usually, this increase lasts no more than two weeks. If the level of ASO in the blood persists for more than two weeks, this may indicate an acute form of the course of the disease or the presence of a chronic systemic disease. A longer increase in ASO titer may indicate the development of rheumatism.

Norm

For correct diagnosis in the laboratory, the level of ASO in the blood is assessed in accordance with accepted standards. The norm of a blood test for ASO in adults is the content of antibody titer less than 200 U / g, in children - less than 150 U / g.

Training

For a study on antistreptolysin O, the patient is carried out. It is recommended to have dinner the day before no later than 8-10 hours before the test. The day before the study, it is necessary to refuse fatty foods, exclude physical activity and alcohol. in the morning. Compliance with these requirements in preparation for the analysis will eliminate the erroneous diagnosis.

To obtain a diagnostically reliable picture of the level of antistreptolysin O in the blood, the analysis must be repeated after one week.

Blood analysis for ASO is an important means of early detection of pathological conditions of the body.

To understand what an elevated ASLO titer means, you should clearly know what parameters this analysis reflects. The name ASLO is an abbreviation of the term - antistreptolysin O. In turn, antistreptolysin O is a type of antibodiesproduced by cells of the immune system against streptococci of groups A, C or G that have entered the human body. ASLO are antibodies developed by the immune system to suppress streptococcal infection. Thus, the analysis of ASLO is the detection of antibodies to streptococci. The result of the ASLO analysis is expressed in titers and indicates the amount of antibodies to streptococci.

After the development of a streptococcal infection (for example, tonsillitis, scarlet fever, erysipelas, etc.), ASLO begins to accumulate in the human body. However, an increase in the ASLO level does not occur in the first days of the disease, but only after 3 to 5 weeks from the moment streptococcus enters the human body. Thus, at the time of the active course of a streptococcal infection, for example, tonsillitis, the ASLO titer will be normal. But 3-5 weeks later from the onset of the disease, the ASLO titer will be higher than normal. After a streptococcal infection, the ASLO titer will remain elevated for another 6 to 12 months, after which it will return to normal values.

Thus, an elevated ASLO titer means that the person has had some kind of streptococcal infection in the previous 6 to 12 months. Moreover, an increased level of ASLO does not in any way reflect the likelihood of developing complications of streptococcal infection in the heart, joints, kidneys and nervous system. An elevated ASLO titer only indicates that there was contact with a streptococcal infection during the previous 6 to 12 months, counting from the moment of the analysis.

However, if an active streptococcal infection occurs in the human body, then the ASLO titer will not decrease, but will remain constantly high. An elevated ASLO titer is observed in rheumatism caused by streptococci. The presence of an elevated ASLO titer makes it possible to distinguish rheumatism from rheumatoid arthritis. Moreover, in rheumatism, the following behavior of the ASLO titer is characteristic:

• During the period of exacerbation of rheumatism, the ASLO titer increases significantly;


• During the period of remission of rheumatism, the ASLO titer decreases compared to the figures at the time of exacerbation, but does not reach the norm, remaining still elevated.

Due to these patterns, the value of the ASLO titer can be used to control treatment and monitor the dynamics of the pathological process. Moreover, the serial determination of the ASLO titer with an interval between two points of the study of 1–2 weeks has the maximum diagnostic value. Such serial studies make it possible to evaluate the dynamics of the ASLO titer and, accordingly, to determine the course of the pathological process in rheumatism.

In addition to rheumatism and previous streptococcal infections, ASLO titer may be elevated in the following cases:

• Some healthy carriers

If antistreptolysin O is elevated in the patient's blood, then this indicates the presence of a streptococcal infection in the body. Such an analysis is not used for the urgent diagnosis of diseases caused by these bacteria. After all, antibodies to streptococcus appear in the blood only on the eighth day of the disease. A month after the first manifestations of pathology, their number reaches a maximum. However, streptococcal infections often produce complications such as glomerulonephritis and rheumatism. In order to detect the consequences early, this analysis is prescribed.

What is antistreptolysin?

(ASL-O) is an antibody that neutralizes the group A streptococcal enzyme (streptolysin). When bacteria enter the body, ASL-O recognizes their antigens and interacts with them. Proteins - immunoglobulins - also participate in this process. As a result, bacterial toxins are neutralized and excreted from the body.

The more bacteria in the body, the more antibodies are required to neutralize them. If ASL-O is elevated in the analysis, then this indicates the presence of group A streptococci.

Indications for research

A blood test for antistreptolysin O is prescribed if a streptococcal infection is suspected. Indications for research are the following pathologies:

• angina;
• scarlet fever;
• rheumatic diseases;
• otitis;
• osteomyelitis;
• glomerulonephritis;
• myocarditis;
• PANDAS syndrome (tics and mental disorders in children after a sore throat or scarlet fever).

It should be remembered that antibodies return to normal only 6-12 months after the infection. Therefore, even after recovery, a person may have increased antistreptolysin O. However, if such an analysis is performed for rheumatism, myocarditis or glomerulonephritis, then its results help to identify the etiology of the disease. If the level of antibodies to streptolysin is elevated in the blood, then most likely, rheumatic or renal pathology is a complication of streptococcal infection.

How is the analysis carried out?

For analysis, blood is taken from a vein. The antibody titer is then determined using a special latex agglutination test. In this way, the concentration of antistreptolysin O can be quickly determined.

A more complex diagnostic method is the study of blood using a photometer and a spectrophotometer. This allows accurate quantitative measurement of antibody levels.

Usually, when testing blood for ASL-O, other immunological indicators are also determined:

• total protein;
• uric acid;
• C-reactive protein;
• circulating immune complexes.

Before passing the analysis, the following rules must be observed:

1. The last meal should be no later than 8-12 hours before the study.
2. On the eve of the analysis exclude physical activity.
3. The day before the test exclude the use of alcohol.
4. Within 1 hour before the study, you must refrain from smoking.
5. Before the analysis, it is undesirable to take medication. If the patient constantly uses any medications, then this should be reported to the doctor.

It should be remembered that sometimes antistreptolysin O is elevated for random reasons. The analysis may give false readings if the patient has used drugs, alcoholic beverages, or smoked. Therefore, it is necessary to strictly adhere to the above rules. This is necessary for the reliability of the results of the study.

Analysis norms

Normally, antistreptolysin O should not be present in the blood. If antibodies to streptolysin are not detected, this means that the patient has not experienced streptococcal infection in the last 6 months.

However, if antibodies are determined in a very small amount, then this does not indicate pathology. The maximum allowable ASL O values ​​are shown in the table below.

Causes of an increase in antibodies

If antistreptolysin O is slightly elevated, then this indicates that the person has recently become infected with streptococcus A. If the antibody titer significantly exceeds the norm, then this indicates a long-standing presence of infection in the body.

If, after the start of treatment, the ASL-O index gradually decreases, then this indicates that the therapy is chosen correctly.

An increased titer of antibodies to streptolysin can be observed in the following pathologies:

• angina;
• myocarditis;
• hepatic pathologies;
• rheumatism;
• scarlet fever;
• erysipelas.

In some cases, an increase in ASL-O can be observed in healthy people. Therefore, it is necessary to pay attention to other indicators of the analysis, such as the level of total protein and the presence of paraproteins.

What to do with an increased antibody titer?

What to do if antistreptolysin O is elevated in the blood? Treatment is prescribed only after additional research. It is necessary to pass the following tests:

• biochemical blood test;
• test for creatine phosphokinase and lactate dehydrogenase.

If the diagnosis is confirmed, then penicillin antibiotic therapy is prescribed:

• "Bicillin";
• "Extencillin".

Additionally, corticosteroids and anti-inflammatory drugs are prescribed.

If the patient has myocarditis, then the following drugs are indicated:

• "Mildronata";
• "Elkara".

With kidney damage (glomerulonephritis), the patient is placed in a hospital. The patient is prescribed a salt-restricted diet. Urine output and blood pressure should be monitored daily.

The main method of treatment of streptococcal infection and its complications is antibiotic therapy. However, it should be remembered that antibacterial drugs adversely affect the intestinal microflora. Therefore, it is necessary to take probiotics and try to consume sour-milk products more often. The use of immunomodulators is also shown. Only an integrated approach to therapy will help to cope with streptococcal infection.

What is ASLO? This is the name of antibodies against a special type of microorganisms: when a person becomes ill with one of the many varieties of streptococcal infection, antibodies called antistreptolysin O are produced in his body. For greater convenience in medicine, it is abbreviated as ASLO.

The ASLO index is a marker of the presence of the β-hemolytic streptococcus group A antigen (GABHS) in the body. This harmful microorganism occupies the skin and mucous membranes, has an affinity for connective tissue, causing rheumatism. If the level of ASLO in the blood is elevated, this is a symptom of diseases caused by GABHS. These include, for example, tonsillitis and scarlet fever. If a biochemical blood test did not reveal this antigen in a person or its proportion is negligible, then there is no reason for concern, this is a completely normal state of the body. Such results are not only direct evidence of the absence of infection, but also that the person has not had to deal with streptococcus over the past 6 months.

Antistreptolysin O or ASL - O

Before finding out the level of ASLO in the blood, what it is, let's learn more about the antigenic structure of streptococcus. This will help to better understand the pattern of antibody production.

Gram-positive streptococci secrete enzymes. One such enzyme is streptolysin. It plays an important role in the formation of the immune response, and is toxic to the tissues of the heart, it can cause a rise in temperature, a rash with scarlet fever.

The body reacts to this aggression by secreting antistreptolysin O. This is how the immune system tries to protect the targets - the mucous membranes and the epidermis. But such antibodies can only eliminate the waste products of bacteria; they are powerless against streptococcus itself. Therefore, proper and timely treatment is indispensable.

But when making a diagnosis, it is still worth considering the nuances of increasing the number of antibodies in a blood test:

• The beginning of the increase in concentration occurs only at 3-5 weeks of infection;
• After reaching the maximum mark, the level decreases;
• High ASLO results can last from 6 months. up to a year;
• If measures were not taken in time, and the concentration of antistreptozilin was high for a long time, then this can result in complications in the form of rheumatic fever. In this case, the stabilization of indicators occurs after 4-8 months;
• If within 6 months the level of ASLO remains high, then the patient should expect a relapse of the disease, and you need to prepare for an attack.

It is worth noting that in 15% of those infected, antistreptolysin remains at a normal level, so you should not rely on this analysis alone, without taking into account other methods.

A short video about streptococcus:

Indications for examination

For timely diagnosis, as well as monitoring the course of the disease, a blood test for antistreptolysin is prescribed.

Group A streptococcus can cause diseases such as:

• scarlet fever;
• face;
• tonsillitis (tonsillitis);
• Pyoderma - a purulent lesion of the skin;
• rheumatic fever;
• Glomerulonephritis - damage to the renal glomeruli.

Without timely medical intervention, the likelihood of complications increases significantly. Can be affected:

• joints;
• cardiac muscle;
• Renal nephrons;
• Nervous system.

All this helps to prevent the determination of the ASLO level. Abroad, the passage of such an examination for diseases of the heart, kidneys, nervous system is mandatory for children. And even a year after they have been cured, experts prescribe a second analysis for antistreptolysin - O. This is done to make a more accurate diagnosis, as well as to exclude the possibility of relapse.

It is assigned to solve the following tasks:

1. To identify the fact that the patient was recently infected with streptococcus A;
2. Assess his current condition and predict the further course of the disease;
3. Identify arthritis in acute rheumatic fever;
4. Assessment of the condition after 2 weeks of therapy for rheumatism and glomerulonephritis.

A blood test for ASLO is prescribed for all patients suffering from the following ailments:

1. Arthritis;
2. arthrosis;
3. Pain in the back;
4. Pharyngitis is an inflammatory process in the mucous membrane and lymphocyte tissue;
5. Angina;
6. Laryngitis;
7. Tracheitis - inflammation in the trachea;
8. Nasopharyngitis - inflammation of the nasopharynx;
9. Scarlet fever.

Biochemical examination is one of the obligatory items of the examination program for patients with rheumatism, glomerulonephritis and myocarditis.

In dispensary treatment, patients have to donate blood 2 times a year before starting an anti-relapse course of therapy. The first delivery is made 30 days after the transferred infectious diseases of the respiratory system. The concentration of antibodies begins to rise during this period, reaching a peak value at week 6. Control blood sampling is done six months later, because that is how much the body needs for complete recovery.

Preparation for visiting the laboratory

As with any examination, donating blood for ASLO has its own “tricks” to obtain the most accurate results. Preparing the body for a visit to the laboratory includes the following items:

1. Last meal 8-12 hours before;
2. After undergoing antimicrobial or antibacterial therapy, at least 3 weeks must pass;
3. Limit the intake of medications on the eve of blood donation;
4. For 24 hours it is prescribed to follow a diet. Sweet, salty, spicy, flour and meat are excluded from the diet;
5. Give up bad habits in 7 days. In particular, do not drink strong drinks.

You need to visit the laboratory in the morning, before 11.00

How is the research done?

What is ASLO analysis and how is it performed? For the study, venous blood is taken from the patient. To do this, use a syringe with a volume of 10 ml.

There are several methods for determining antistreptolysin O (ASLO). The most popular is the latex test. Carrying out this analysis does not require much time and cost. With its help, you can not only detect a high content of antibodies in the blood, but also determine their titer (the mass of a substance in a milliliter of serum). Carry out the procedure as follows:

• Pre-frozen reagents and blood samples are warmed to room temperature;
• A drop of biomaterial is placed on 2 separate glasses;
• A positive control is added to the first sample, and a negative control to the second;
• The next step is to add the latex reagent;
• After the sample is stirred;
• The glass is then rotated using a mechanical rotor.

A result greater than 200 IU/ml should mean that the test for the presence of streptococcus bacteria is positive.

There are medical professionals who prefer another technique - turbidimetric titration. This method is good when quantitative measurements are needed. To do this, use such devices as:

• Photometer;
• Spectrophotometer.

ASLO blood cannot be donated 1 time - this will not provide all the necessary information for diagnosis and prognosis. That is why, to monitor the dynamics of the development of the disease, it is carried out 2 times with a break of 7 days, that is, 1 time per week.

ASLO norm in a blood test

If the result obtained in adults or children is 0, this is a completely normal result. The main thing is that the upper limit of the standards is not exceeded. ASL O norm depends on the age of the child. The table below shows the limit values:

In women, as well as in men, the upper limit of the standard is 200 U / ml. There is some increase in the norm in children, which corresponds to the age of various streptococcal infections - childhood sore throats, and so on, therefore, there are methods according to which the upper limit of the norm is higher in children from 7 to 14 years old than in adults.

Deciphering possible results

• In 85% of patients with acute rheumatic fever;
• Diffuse glomerulonephritis;
• Erysipelas;
• Otite;
• Chronic tonsillitis;
• scarlet fever;
• osteomyelitis;
• Pyoderma.

Also, a low level of antibodies is observed in babies at the age of 6 months. - 2 years. Low results in diagnostics do not play an important role, so a detailed interpretation of the data is not required. This can happen as a result of:

• Medications: antibiotics, glucocorticosteroids;
• Nephrotic syndrome (false negative result);
• liver problems;
• Hypercholesterolemia.

To double-check the information received, the patient is sent for re-testing after 10 days.

This pathogen, group A β-hemolytic streptococcus, quite often provokes the appearance of secondary infectious diseases. Naturally, in this case, since the bacteria will have already settled in the body by that time (active reproduction, production of toxins). Complications in the form of secondary infections can be:

• Meningitis;
• Infectious - toxic shock;
• Purulent otitis;
• pyoderma;
• Sepsis;
• Osteomyelitis;
• neurological disorders;
• Endocarditis.

Some patients may develop hypersensitivity to the agent (prone to relapse). What does the analysis result show in such patients? The ASLO level is constantly high.

Therapy

The origin of the inflammatory process plays an important role in the choice of treatment, especially when it comes to a child. If angina should resort to antibiotic therapy, then in other cases, this treatment method is not so effective. The ASLO blood test helps to avoid unnecessary antibiotics and complications.

Additional studies to the above analysis are:

• A smear from the mucous membrane of the oropharynx;
• Analysis of blood and urine.

Based on the data obtained, a group of drugs and their dosage are selected. It also takes into account the individual characteristics of the organism, for example, the presence of allergies.

The most popular drugs for adults are:

• "Ampicillin";
• "Amoxiclav"
• "Augmentin".

Take them 2 times a day for 500-1000 mg. The course of treatment is 10 days.

In addition, they take antihistamines ("Suprastin"), anti-inflammatory ("Acetylsalicylic acid" 500 mg 3 times a day, for a week), immuno-strengthening ("Immunal", tincture of ezinacea) and means for normalizing the intestinal microflora (Linex, Hilak-forte) . It is worth thinking about nutrition. Increase the intake of fermented milk products (ryazhenka, sour cream, cottage cheese, kefir).