With reactive protein SRP latex test. What is SRP in the blood? C-reactive protein - what is it?

The materials are published for informational purposes only and are not a prescription for treatment! We recommend that you consult a hematologist at your medical institution!

CRP is one of the mandatory indicators that are determined during a biochemical blood test. It helps to identify even minimal inflammation, which helps speed up the process of diagnosis and treatment. In addition, C-reactive protein is interesting from a scientific point of view. Scientists have already discovered its role in the pathogenesis of heart disease.

The CRP test is a quick and accurate way to detect the presence of inflammatory processes in the body. CRP (C-reactive protein) is a fast (acute) phase protein that is produced by the liver as a means of fighting inflammation. CRP is one of the indicators of biochemical processes occurring in the body.

Protein levels depend on the degree of inflammation. Normally, CRP should not be detected in a biochemical blood test in a healthy person or may be in a very small amount - up to 4.5 mg/liter.

Role of C-reactive protein

CRP is a diagnostically significant and reliable indicator of disorders in the body. It is not for nothing that it is so often prescribed as a study by clinicians. C-reactive protein performs the following important functions in the body:

• participates in the recognition of microbial agents. It reacts to the polysaccharide cell wall of bacteria, entering into a precipitation reaction with it;
• is a “bait” for phagocytes, absorbing pathogenic microorganisms;
• removes phospholipid residues from cell membranes formed as a result of the alterative (damaging) phase of inflammation;
• activation of the complement system and lymphocytes (involvement of humoral immunity).

Important. The lipid parts of destroyed cell membranes are themselves aggressive mediators of inflammation, promoting hemolysis of red blood cells and the formation of antibodies.

In the acute phase of inflammation, the CRP indicator in a biochemical blood test can increase 30 or even 300 times.

Note. It is believed that C-reactive protein plays an important role in the pathogenesis of atherosclerosis, including in diseases such as coronary heart disease. In patients with myocardial infarction, CRP increases at least 20 times.

Purpose of the CRP test

C-reactive protein is used to detect:

• acute infectious process;
• acute or aggravated chronic disease (nephritis, gastritis, colitis, hepatitis, pancreatitis, pneumonia, rheumatism);
• allergic reaction (as an additional confirmation method);
• IHD with stenosing coronary sclerosis and/or myocardial infarction;
• the effect of treatment - both medicinal and surgical. With proper therapy, CRP quickly disappears from the blood.

Important! C-reactive protein is more valuable as an indicator of the presence of inflammation than ESR and white blood cell count. This is a very sensitive and fast-reacting indicator.

• oncological diseases and metastases;
• burn toxemia (stage 1 of burn disease);
• injuries;
• autoimmune damage (thyroiditis, lupus, etc.);
• eating fatty and unhealthy foods.

Probable diseases

Depending on the degree of increase in CRP, the presence of various pathologies can be suspected:

• sluggish chronic diseases, cancer in the initial stages, localized viral infections give a slight increase in CRP - in the range of 5-30 mg/l;
• exacerbations of chronic pathology, bacterial infections, operations, myocardial infarction in the acute and acute stages give an increase in CRP of approximately 40-200 mg/l;
• generalized infections, septicemia, large area of ​​burns can increase C-reactive protein to a level of 250 mg/l or more.

Important! Against the background of complete well-being (no complaints of pain, malaise, weakness), the detection of increased concentrations of CRP in a biochemical blood test is a serious diagnostic sign and a reason for a mandatory more in-depth examination.

The role of CRP in the diagnosis of cardiovascular diseases

Determining the concentration of acute phase C-reactive protein helps cardiologists in the following cases:

• predicting complications in coronary artery disease and hypertension;
• determination of the width of the necrosis zone during myocardial infarction;
• assessment of the effectiveness of therapy after a course of treatment for ischemic heart disease (various types of angina), hypertension or heart attack;
• after heart surgery to determine the prognosis of mortality.

C-reactive protein (CRP) is a golden marker that is responsible for the presence of inflammatory processes in the body.

Analysis for this element allows you to identify an infection or virus in the body at an early stage.

Its increase occurs within 6 hours from the onset of the inflammatory process, but additional research may be required to make an accurate diagnosis.

What it is?

C-reactive protein (CRP) is an indicator of acute inflammation. It is produced by the liver, and this is done during necrotic and inflammatory processes in any part of the body. In clinical diagnostics, it is used along with ESR, but has higher sensitivity.

Reactive protein can only be detected using a biochemical blood test. It increases in the blood within 6-12 hours from the onset of the pathological process. CRP responds well to therapeutic methods, which makes it possible to monitor the progress of treatment using a simple analysis.

In contrast to ESR, C-reactive protein returns to normal values ​​immediately after inflammatory processes have resolved and the patient’s condition has normalized. High ESR values, even after successful treatment, can persist for a month or more.

Indications for use

Most often, determination of the amount of reactive protein is prescribed for:

• Calculation of the risks of heart and vascular pathologies.
• After clinical examination of elderly patients.
• Postoperative period.
• Assessing the effectiveness of drug therapy.
• Diagnosis of autoimmune and rheumatic diseases.
• Suspicion of a tumor.
• Infectious diseases.

Laboratory testing of CRP is usually prescribed for acute inflammatory diseases of an infectious nature. It also helps in identifying pathologies of an autoimmune and rheumatic nature. It is prescribed for suspected tumors and cancer.

How is C-reactive protein determined?

Determination of C-reactive protein occurs through a biochemical blood test. To do this, use a latex test based on latex agglutination, which allows you to get a result in less than half an hour.

You can get tested in almost any laboratory. One of the most popular laboratories in all Russian cities is Invitro, where specialists will help you get results within a few hours after blood sampling.

Reactive protein concentration plays an important role in the diagnosis of cardiovascular pathologies .

In this case, conventional methods for detecting reactive protein do not suit cardiologists, and the use of highly accurate hs-CRP measurement, which is combined with a lipid spectrum, is required.

A similar study is carried out for:

• Pathologies of the excretory system.
• Difficult pregnancy.
• Diabetes mellitus.
• Lupus erythematosus.

Functions

Reactive protein is an immune stimulant that is produced during acute inflammatory processes.

During the process of inflammation, a kind of barrier arises that localizes microbes at the sites of their invasion.

This prevents them from entering the bloodstream and causing further infection. At this time, pathogens begin to be produced that destroy the infection, during which reactive protein is released.

An increase in reactive protein occurs 6 hours after the onset of inflammation and reaches its maximum on the 3rd day. During acute infectious pathologies, the level can exceed the permissible value by 10,000 times.

After the inflammatory reaction ceases, the production of reactive protein stops and its concentration in the blood decreases.

The SRB performs the following functions:

• Accelerate the mobility of leukocytes.
• Activate the complement system.
• Produce interleukins.
• Accelerate phagocytosis.
• Interact with B- and T-lymphocytes.

C-reactive protein is normal

Changes in indicators are carried out in mg. per liter If there are no inflammatory processes in the adult’s body, reactive protein is not detected in his blood. But this does not mean that it is not present in the body at all - its concentration is so low that tests cannot detect it.

The norms for adults and children are presented in the table:

If the reactive protein exceeds 10, a number of other studies are carried out to determine the cause of the inflammatory process. You need to be especially careful with high levels in newborns and children, which indicate a malfunction in the body.

Erythrocyte sedimentation rate (ESR) can also detect inflammation, but not at an early stage. The standards for ESR indicators have some differences:

ESR is an older and simpler method for detecting inflammatory processes, which is still used in many laboratories. The creative protein test is more accurate and allows you to get a reliable result at an early stage of the inflammatory process.

The advantages of analysis for C-reactive protein compared to ESR are indicated in the table:

Differential diagnosis is presented in the table:

Reasons for the increase

Elevated reactive protein indicates the presence of inflammatory and infectious diseases. Depending on the degree of increase in indicators, one or another pathology can be suspected.

There are many reasons for an increase in c-reactive protein and the more serious the pathology, the higher the indicators.

High protein levels may indicate:

After surgical interventions, the CRP value is especially increased in the first hours, after which a rapid decrease occurs. Even excess body weight can cause an increase in reactive protein.

The most common reasons for a slight increase include:

The increase in CRP in tonsillitis is indicated in the table:

Most often, reactive protein increases due to inflammatory diseases of an infectious nature.

The exact cause of the increase in indicators can be determined by additional symptoms, and if they are completely absent, the specialist will suggest taking a number of other tests:

Highly sensitive hs-CRP test

To identify pathologies of the cardiovascular system, a special highly sensitive hs-CRP test is performed. It allows you to detect even a slight increase in protein, which undoubtedly helps in calculating the risks of heart and vascular diseases.

In women and men, the risk of cardiovascular pathologies is most often determined using a cholesterol test. The Hs-CRP test provides more accurate data and helps to start treatment at an early stage. It is indispensable in monitoring the effectiveness of treatment and the course of the disease.

Analysis for c-reactive protein is important for making a diagnosis and identifying problems in the body. It allows you to determine the presence of serious pathologies at the initial stage and monitor the effectiveness of therapeutic measures. Unlike ESR, analysis for CRP gives a more accurate result and tracks the slightest changes in the body.

Video: C reactive protein 10

Blood, showing the activity of reactive protein, is the most accurate and fastest method of confirming or denying the presence of an inflammatory process in the body.

What is SRB?

Due to timely and effective treatment, a biochemical blood test for CRP will reflect a reduction in concentration within a few days. The level will approach normal within 7-14 days from the start of taking the medication. If the disease has developed from an acute to a chronic form, then the concentration of CRP will gradually reach zero. But if the disease progresses to an acute stage, the rate will increase again.

What does a CRP blood test show?

The study allows you to distinguish a bacterial infection from a viral one. This is due to the fact that in a viral disease the protein level is slightly increased. But in the presence of a disease of a bacterial nature, even if it is only in the initial stage of development, the activity level of C-reactive protein in the blood serum increases several times.

Normally, a biochemical blood test for CRP, which reflects the activity of reactive protein in a healthy person, should show a negative result.

Indications for donating blood

The attending physician may refer his patient for a blood test for CRP in the following situations:

Preparing for this study

The material for a blood test reflecting the activity of reactive protein is venous blood. For the most reliable results when decoding a biochemical blood test, SRB, you must adhere to the following rules on the eve of the test:

Decoding the results

The results of a blood test for CRP can be summed up by your attending physician. Only a qualified specialist can accurately assess how much C-reactive protein has increased, as well as correlate this information with symptoms and prescribe appropriate therapy.

When reading a blood test for CRP, the result should normally be negative, but despite this, the accepted reference values ​​are 0-5 mg/l. Next, let us consider in more detail the results of the analysis showing the activity of the reactive protein:

• Less than 1 mg/l indicates a low probability of developing pathologies of the cardiovascular system and the occurrence of their complications.
• From 1 to 3 mg/l - indicates the average probability of developing diseases of the cardiovascular system and the occurrence of their complications.
• More than 3 mg/l means a high probability of developing cardiovascular pathologies in practically healthy patients, and also indicates a high probability of developing complications in patients.
• More than 10 mg/l - in this case, there is a need for a repeat blood test and additional diagnostic examination in order to determine the cause of the disease.

The normal range for CRP blood tests in women, men and children ranges from 0 to 5 mg/l. The normal level of C-reactive protein in the blood of newborns is 0-1.6 mg/l.

Thus, we can conclude: deciphering blood tests for CRP in adults and children shows that the norm for them is almost the same values.

CRP level during pregnancy

Elevated CRP levels are not dangerous for pregnant women, provided other tests are normal. Otherwise, there is a need to search for the cause of inflammation. During toxicosis, the level can increase to 115 mg/l. If the indicator increases to 8 mg/l during the period from the 5th to the 19th week of pregnancy, then there is a risk of miscarriage. The cause of an increase in CRP can be bacterial (over 180 mg/l) and viral infections (less than 19 mg/l).

For what reasons is the norm violated?

An increase in the concentration of C-reactive protein in a person indicates the presence of pathological changes. This indicator may increase by only a couple of units within the established norms, or it may increase exponentially, which allows us to evaluate the changes occurring in the patient’s body.

The level of reactive protein activity in the blood serum could deviate from the norm for the following reasons:

What can affect the result?

Various factors can lead to abnormalities in the SBR blood test.

Causes of elevated C-reactive protein include pregnancy, excessive physical activity, use of combined contraceptives, smoking, hormone replacement therapy, drinking alcohol immediately before the test, and the presence of implants.

Taking beta blockers, corticosteroids, statin drugs and non-steroidal anti-inflammatory drugs (aspirin, ibuprofen) will help reduce the concentration of C-reactive protein.

To determine the baseline C-reactive protein level, it is necessary to take CRP blood tests every two weeks after the disappearance of symptoms of any chronic or acute disease.

Let's sum it up

So, based on the above, we can draw the following conclusions.

For quite a long time, a blood test for the concentration of C-reactive protein remains a fairly informative indicator of the development of diseases. Even the emergence of the newest technologies is not able to displace it from medical practice.

Timely warning from a qualified physician will help determine the reliability of the test results. There have been cases when the attending physician had to prohibit further use of medications or postpone the date of the analysis to determine the concentration of CRP until the end of the patient’s course of treatment.

It is worth remembering that during pregnancy in women with toxicosis in the early and late stages, the activity of reactive protein in the blood may be increased.

SRP latex test Set No. 1 250 determinations (Set of reagents for determining C-reactive protein in the latex agglutination reaction (qualitative and quantitative analysis) (12.01)

Instructions for useset of reagents"SRB LATEX-TEST"

Set of reagents for determinationC-reactive protein in latex agglutination reaction

Registration certificate No. FSR 2011/12205 dated 03.11.11

To identify and determine the content of CRP in human serum using the latex agglutination reaction (RAL). CRP is an acute phase protein, the concentration of which increases during inflammatory processes, tissue damage, bacteremia and viral infections. In inflammatory processes associated with bacterial infections, the concentration of CRP can increase to 300 mg/l in 12-24 hours.

1. SET CHARACTERISTICS

2.1. Operating principle

If CRP is present in the test sample, it interacts with the corresponding antibodies located on the surface of latex particles. The result of the interaction is agglutination of latex with the formation of small or large grains that are visually distinguishable.

2.2. Set contents

SRB latex reagent– a suspension of monodisperse polystyrene latex with immunoglobulin (IgG) to human SRP immobilized on the surface of its particles; a white suspension, during storage it separates into a white precipitate, easily broken by shaking, and a colorless transparent or slightly opalescent supernatant liquid. The sensitivity of SRP latex is calibrated against the reference material CRM 470/RPPHS.

Saline solution (PS)– 0.9% sodium chloride solution; contains a preservative - sodium azide in a final concentration of 0.1%; clear colorless liquid

Positive control serum (K+)— liquid human blood serum, inactivated by heating at 56° C for 1 hour, containing CRP in a concentration of at least 12 mg/l, giving a negative reaction to HBsAg and not containing antibodies to HIV-1, HIV-2 and HCV; preservative – sodium azide, final concentration 0.1%. Transparent colorless or yellowish to red-brownish liquid.

Negative control serum (K –)– liquid human blood serum, inactivated by heating at 56° C for 1 hour, containing CRP in a concentration of less than 6 mg/l, giving a negative reaction to HBsAg and not containing antibodies to HIV-1, HIV-2 and HCV; preservative – sodium azide, final concentration 0.1%. Transparent or yellowish liquid.

1. ANALYTICAL AND DIAGNOSTIC CHARACTERISTICS OF THE KIT

The kit is designed to carry out 250 studies, including control samples.

The kit allows you to detect CRP in undiluted human serum at concentrations of 6 mg/l and higher.

1. PRECAUTIONARY MEASURES

The kit is biologically safe, but when handling test serum samples, they must be treated as potentially infectious materials.

1. EQUIPMENT AND MATERIALS

— Orbital shaker (any brand with a vibration amplitude of 10-20 mm).

— Graduated pipettes of class 2 accuracy or pipette dispensers.

— Automatic micropipettes or stirring pipettes (20 µl).

Glass or plastic rods.

— Clock or timer.

1. SAMPLES STUDYED

Freshly obtained blood serum is used. The use of blood plasma as samples is not permitted. Blood collection should be done according to standard procedure. Samples can be stored for 7 days at 2-8 ˚С or 3 months at minus 20 ˚С. Do not subject samples to repeated freezing and thawing.

The serum being tested must be transparent and free of suspended particles.

Do not use hemolyzed or contaminated samples.

1. CONDUCTING THE ANALYSIS

7.1. Preparation of reagents and materials

Keep all components of the kit and test samples for at least 20 minutes at room temperature. Lightly shake the bottle and thoroughly mix the SRB-latex reagent. Control sera and saline are ready for use.

Prepare additional equipment:

• glass plate or card for staging the reaction;
• automatic micropipettes or stirring pipettes (10-50 µl);
• glass or plastic rods;
• clock or timer.

7.2. Qualitative definition

Apply 20 μl of K + to the first cell of the card, and 20 μl of K – to the adjacent cell of the card. Apply 20 µl of the test samples to the free cells of the card.

Add 20 µl of thoroughly mixed SRP-latex reagent to each sample well. Using the flat end of a stirring pipette (glass rod), carefully mix each drop, distributing the reaction mixture over the entire area of ​​the cell. For each drop, use a new stirring pipette (glass rod).

7.3. Semi-quantitative determination

Directly on the reaction card, prepare the following dilutions of the test sample in 9 g/l physiological solution: 1:2, 1:4, 1:8, 1:16, 1:32 and 1:64. If necessary, the number of dilutions can be increased.

Lightly shake the vial to mix the CRP-latex reagent and add 20 µl to each cell with a dilution of the test sample, then mix each drop as indicated above for qualitative determination.

Rock the card manually or on a shaker for 2 minutes, then immediately record the reaction results.

1. REGISTRATION AND ACCOUNTING OF RESULTS

The results are recorded visually against a dark background after adding the reagent to the test sample no later than 2 minutes; with later recording, false positive results may be obtained.

Positive RAL is considered to be the presence of latex agglutination (any appearance of graininess or distinguishable particles).

Negative RAL is considered to be the absence of agglutination (the liquid in the cell remains cloudy and homogeneous).

Results of the reaction with the test samples are taken into account only if the reaction is positive with K + and negative with K –.

Qualitative definition

A positive reaction indicates the presence of CRP in the test serum at a concentration of more than 6 mg/l. All samples that give a positive reaction are subject to additional quantitative research.

A negative reaction indicates that the CRP concentration is less than 6 mg/l.

quantitation

Based on the results of sample titration, determine the reciprocal of the SRP titer.

CRP concentration (mg/l) = 6 mg/l×(reciprocal of sample titer)

where 6 mg/l is the minimum concentration of SRP determined in the RAL;

Example:

The titer of the test sample with positive RAL is 1:32;

SRP concentration =6 mg/l x32 = 192 mg/l

If the concentration of CRP in the sample is more than 1600 mg/l, a prozone effect may be observed. To avoid this, it is recommended to dilute the serum.

With timely and effective treatment, a CRP blood test will show a decrease in protein concentration within a few days. The indicator normalizes 7-14 days after starting medication. If the disease has passed from the acute stage to the chronic stage, then the value of C-reactive protein in the blood serum will gradually become zero. But as the disease worsens, it will increase again.

A biochemical blood test, CRP, makes it possible to distinguish a viral infection from a bacterial one. Since with the viral nature of the disease, the protein level does not increase much. But with a bacterial infection, even if it has just begun to develop, the concentration of C-reactive protein in the blood increases exponentially.

In a healthy person, CRP is normally negative.

When to send for a biochemical blood test CRP

The doctor sends the patient a biochemical blood test for CRP in the following cases:

1. Preventive examination of elderly patients.
2. Determination of the likelihood of cardiovascular complications in patients with diabetes, atherosclerosis, and on hemodialysis.
3. Examination of patients with hypertension, coronary heart disease to prevent possible complications: sudden cardiac death, stroke, myocardial infarction.
4. Identification of complications after coronary bypass surgery.
5. Assessing the risk of restenosis, recurrent myocardial infarction, and death after angioplasty in patients with acute coronary syndrome or exertional angina.
6. Monitoring the effectiveness of prevention and treatment of cardiovascular complications using statins and acetylsalicylic acid (aspirin) in patients with cardiac problems.
7. Collagenosis (to determine the effectiveness of therapy and the reactivity of the process).
8. Monitoring the effectiveness of treatment of bacterial infections (for example, meningitis, neonatal sepsis) with antibacterial drugs.
9. Monitoring the effectiveness of treatment of chronic diseases (amyloidosis).
10. Neoplasms.
11. Acute infectious diseases.

How to prepare for analysis

Venous blood is donated for a biochemical blood test for CRP. On the eve of blood sampling, you must adhere to simple rules:

• Do not drink alcohol, fatty or fried foods.
• Try to avoid physical and emotional stress.
• Last meal 12 hours before analysis.
• You should not drink juice, tea or coffee before the test. You can quench your thirst only with still water.
• You should not smoke 30 minutes before donating blood.

Analysis transcript

The CRP blood test must be deciphered by a doctor. Only a specialist will be able to correctly assess how much the C-reactive protein level has increased, compare this with the symptoms and prescribe appropriate treatment.

Although the normal biochemical blood test for CRP is negative, reference positive values ​​of 0 to 5 mg/l are accepted. Let's look at the indicators of DRR and condition, they are shown in the table.

C-reactive protein during pregnancy

Elevated CRP levels are not dangerous for a pregnant woman if other tests are normal. Otherwise, it is necessary to look for the cause of the inflammatory process. With toxicosis, readings may increase to 115 mg/l. When increasing to 8 mg/l from 5 to 19 weeks, there is a risk of miscarriage. The reason for an increase in CRP can be viral infections (if the indicator is up to 19 mg/l), bacterial infections (if the indicator is above 180 mg/l).

Reasons for deviations

• Acute bacterial (neonatal sepsis) and viral (tuberculosis) infections.
• Meningitis.
• Postoperative complications.
• Neutropenia.
• Diseases of the gastrointestinal tract.
• Tissue damage (trauma, burn, surgery, acute myocardial infarction).
• Malignant neoplasms and metastases. (an increase in the level of CRP is observed in cancer of the lungs, prostate, stomach, ovaries and other tumor sites)
• Arterial hypertension.
• Diabetes.
• Excess body weight.
• Hormonal imbalance (increased levels of progesterone or estrogen).
• Systemic rheumatic diseases.
• Atherogenic dyslipidemia (decreased cholesterol levels, increased triglyceride concentrations).
• A chronic inflammatory process associated with an increased likelihood of cardiovascular diseases and the occurrence of their complications.
• Exacerbation of chronic inflammatory (immunopathological and infectious) diseases.
• Reaction of transplant rejection.
• Myocardial infarction (an increased level of CRP is determined on the 2nd day of the disease; by the beginning of the 3rd week, the value of C-reactive protein returns to normal).
• Secondary amyloidosis.

What can affect the analysis result?

Pregnancy, taking oral contraceptives, intense physical activity, hormone replacement therapy, and smoking can cause an increased CRP blood test value.