C reactive protein is an important indicator in a blood test

Causes of appearance in the blood

C reactive protein is produced in liver cells. It consists of carbohydrates and proteins. In the blood of a healthy person, the amount of the substance is minimal, so it is impossible to detect it even with the help of high-precision methods and modern equipment. Increased production of CRP begins only with the development of pathologies that pose a threat to the human body. They can be provoked by a variety of harmful microorganisms: bacteria, viruses, fungi.

CRP appears in increased quantities in the blood during injuries and surgical operations, damage to internal organs and the development of tumors. Also, CRP analysis shows the presence of a substance in the blood during autoimmune reactions of the body, which lead to impaired immunity. In this case, substances are produced that damage healthy tissue.

When C reactive protein in the blood is elevated, this indicates the activation of the natural defense systems of the human body. But at the same time, the substance at high concentrations has a negative effect on fat metabolism, which increases the risk of cholesterol plaques on the walls of blood vessels. That is, if the presence of CRP is confirmed, the likelihood of vascular complications can be assessed by its concentration.

C-reactive protein test: what is it for?

What is C-reactive protein? What can a test result for this substance tell a doctor? What is the normal level of C-reactive protein in the blood? Nikita Valerievich Vorobyov, a neurologist at the Expert Clinic Kursk, answers these and other questions.

— Nikita Valerievich, before we talk about the analysis for C-reactive protein, please tell us what kind of substance this is? Is it present in the body normally or does it appear only during certain diseases? And what is the significance of the C-reactive protein test?

— C-reactive protein is a kind of indicator of various diseases, the most sensitive marker of the inflammatory process. With its help, the doctor can determine the severity of inflammation in the body. This substance is synthesized by liver cells in response to inflammatory processes in the body: during tissue damage, cell necrosis, during an infectious process, during exacerbation of chronic diseases, for example, rheumatological ones, including ankylosing spondylitis.

Being in the body within normal concentrations, C-reactive protein has a protective function: it initiates immune processes, stimulates phagocytosis (a process in which special blood cells and body tissues - phagocytes - capture and absorb various foreign structures, such as destroyed cells, bacteria, antigen-antibody complexes, etc.).

When the content of C-reactive protein in the blood begins to exceed the norm, this indicates some kind of inflammatory process, the nature of which the doctor will have to find out. Moreover, during acute inflammation, the content of C-reactive protein increases very quickly, literally in 6 hours. Much faster than, for example, ESR changes - the erythrocyte sedimentation rate.

When the treatment itself has already begun, an analysis for C-reactive protein helps the doctor understand what phase the pathology is in: is the acute period still ongoing or the disease has declined.

— What is the normal level of C-reactive protein in the blood?

- Depending on the laboratory, the norm of C-reactive protein varies from 0 to 1 milligram per liter and from 0 to 5 milligrams per liter. There is no lower limit of normal; this protein is detected in the blood only in response to acute inflammation. Within acceptable limits, the level of C-reactive protein can fluctuate during physical activity (for example, after playing sports), smoking, or eating fatty foods.

- Then, it turns out, there is no point in asking under what circumstances C-reactive protein can be lowered? Is this question not valid?

- Right. There are two options: either the protein is normal, or its content is increased. There can be no reduction.

— Why can C-reactive protein be elevated?

— I have already partially answered this question: its content increases with the appearance of inflammatory processes in the body. The reasons for the increase in C-reactive protein may be:

• previous trauma, burn;
• rheumatological disease;
• presence of infection;
• transplant rejection reaction.

The content of this protein also increases during myocardial infarction, after undergoing severe operations.

An analysis for C-reactive protein - I repeat, as an auxiliary study - is used if there is a risk of developing cardiovascular complications, in particular, when diagnosing atherosclerosis: with inflammation of the vascular walls, the concentration of this protein also increases.

— Tell me, how does C-reactive protein behave during pregnancy?

— Since pregnant women have a higher immune system tension than non-pregnant women and, even more so, than men, the content of C-reactive protein during this period may be increased. If the woman is healthy and gestation is normal, this indicator increases from the 16th to the 28th week of pregnancy, then gradually begins to decrease. Then it may increase immediately before childbirth. A high concentration of C-reactive protein in the blood may indicate a risk of developing late toxicosis.

— Which doctor and under what circumstances prescribes a test for C-reactive protein? What might be the reason for this research?

— A general practitioner, therapist, or neurologist can refer a patient for this analysis. But, since this type of research is primarily used in the diagnosis of rheumatological diseases, most often this direction is issued by a rheumatologist.

An analysis for C-reactive protein is carried out, for example, if ankylosing spondylitis is suspected. When making a diagnosis, this study plays an auxiliary role; it is used in conjunction with other markers. When ankylosing spondylitis has already been detected, the doctor can determine by the concentration of C-reactive protein what phase the disease is in - in the stage of exacerbation or remission (the period of weakening or disappearance of the symptoms of the disease).

This test is also prescribed for joint pain, increased body temperature, and infectious processes.

Neurologists use this type of analysis to understand the nature of a patient's back pain.

— Do you always need a referral from a doctor to get tested for C-reactive protein? And if not, what is more correct: to take it as directed or on your own initiative?

— Having a referral for such an analysis is not a prerequisite. But it is still better to do any research after consulting a doctor.

— Does the patient need to somehow prepare for the C-reactive protein test?

— The procedure is a simple blood draw from a vein. No special preparation is required from the patient. The generally accepted rules in such cases apply. The test is taken on an empty stomach, after a 12-14 hour fast (usually this is done in the morning). The day before, 24 hours before the test, you need to avoid drinking alcohol and intense physical activity. It may be necessary to temporarily stop taking certain medications, but only after consultation with your doctor.

1-2 hours before the test, you need to refrain from smoking, tea, coffee, and juices. You can drink still water. Running and quick climbing of stairs should be avoided. It is not recommended to do the study after emotional stress or severe anxiety.

— How long should I wait for the test result?

- Usually no more than one day.

Interviewed by Igor Chichinov

Want to learn more about other tests? Read articles in our “Laboratory Tests” section If you need to get tested for C-reactive protein or other tests, you can sign up here You can make an appointment with specialists here ATTENTION: services are not available in all cities

The editors recommend:

Pain with rheumatoid arthritis: how to help the patient? Are you worried about pain in your lower back? We're talking about sacroiliitis Are you crunchy? What will an MRI of joints tell you?

For reference:

Vorobiev Nikita Valerievich

Graduate of the Faculty of Medicine of Kursk State Medical University in 2021. In 2021, he completed his residency at Kursk State Medical University in the direction of Neurology. Advanced training: interventional methods of treatment in neurology, First Moscow State Medical University named after. THEM. Sechenova, 2021. Advanced training: local therapy of diseases of the musculoskeletal system and compression-neural syndromes, Kursk State Medical University, 2021. Currently, a neurologist at the Expert Clinic Kursk. Receives at the address: st. Karl Liebknecht, 7.

Standard indicators

C reactive protein, the norm of which is universal for all categories of people, makes it possible to detect inflammatory processes in the human body. But it is impossible to make a diagnosis solely on the basis of a CRP blood test.

Today it is believed that the SRP norm is up to 5 mg/l. In newborns, the level can increase to 15 mg/l. When C reactive protein is elevated, suspicions arise about the development of an inflammatory or malignant process. This means that more accurate diagnostics using other methods is required.

But since the use of high-precision equipment makes it possible to determine the minimum amount of a substance in the blood, experts have begun to apply the concept of the basic value of CRP. It was introduced to assess the risks of damage to the heart and blood vessels, in cases where the development of any inflammatory processes is excluded. The norm for the basic indicator of the substance is less than 1 mg/l.

References

1. Kishkun, A.A. Immunological and serological studies in clinical practice. - M.: Medical Information Agency, 2006. - 536 p.
2. Sarapultsev, P.A., Sarapultsev, A.P. The role of c-reactive protein in the acute phase response in myocardial infarction. Cytokines and inflammation, 2013. - T.12. - No. 4. - P. 18-24.
3. Biasucci, M., Liuzzo, G., Colizzi, C. et al. Clinical use of C-reactive protein for the prognostic stratification of patients with ischemic heart disease. Italian heart journal: official journal of the Italian Federation of Cardiology, 2001. - Vol. 2(3). — P. 164-171.
4. Russell, A., Cunninghame, G., Shepherd, C. et al. Polymorphism at the C-reactive protein locus influences gene expression and predisposes to systemic lupus erythematosus. Human molecular genetics, 2004. - Vol. 13(1). — P. 137-147.
5. Mevorach, D., Mascarenhas, J., Gershov, D. et al. Complement-dependent clearance of apoptotic cells by human macrophages. The Journal of experimental medicine, 1998. - Vol. 188(12).

Reasons for the increase

When C reactive protein is elevated, there may be different reasons. Today they are divided into three main groups:

• Oncology.
• Inflammatory processes.
• Vascular pathologies.

The risks of developing certain diseases are assessed by the concentration of the substance in the blood:

• Less than 19 mg/l. This deviation is considered insignificant. Exceeding the norm can be triggered by any negative factor affecting the body. As a rule, in this case, analysis is required at a certain frequency. If constantly elevated CRP is detected, diagnostics are required to exclude autoimmune and oncological pathologies.
• 20-50 mg/l. Indicators always rise to this level with various viral infections.
• More than 100 mg/l. A bacterial infection can provoke a strong immune reaction in the body, against which serious diseases develop: pneumonia, salmonellosis, pyelonephritis, etc.

Complexes with this research

Advanced anti-aging diagnostics in postmenopause Advanced monitoring of age-related changes during postmenopause 29,230 ₽ Composition
Women's check-up No. 1 38 studies for annual preventive examination 19,290 ₽ Composition

Joints 2,620 ₽ Composition

IN OTHER COMPLEXES

• Women's anti-aging diagnostics RUB 12,070
• Advanced male anti-aging diagnostics RUB 33,710
• Inflammation of joints 860 ₽
• Anti-aging diagnostics in postmenopause RUB 12,630
• Men's check-up No. 1 RUB 18,570

What do deviations from the norm mean?

A doctor should interpret the results. Since there is no protein in the blood of a healthy child or its concentration is minimal, there is no need to talk about a reduced level. Exceeding the normal level of CRP in the blood of children as a result of the analysis may indicate:

• up to 30 mg/l – viral diseases, systemic rheumatic pathologies, malignant diseases;
• up to 100 mg/l – acute bacterial infections, exacerbation of chronic and rheumatic pathologies, tissue damage, including after operations;
• up to 300 mg/l – extensive burns, sepsis.

Deviations from the norm are not a diagnosis and require additional examination. Depending on the clinical picture and complaints of the child, treatment can be carried out by otolaryngologists, urologists, dentists, surgeons and other specialized doctors. To establish a diagnosis and develop a treatment plan, doctors prescribe additional instrumental and laboratory tests.

Preparing for the examination

In order for an analysis to detect the level of CRP in the blood to show a reliable result, it is necessary to properly prepare the child for the test:

• stop taking painkillers and antipyretic non-steroidal anti-inflammatory drugs 1-2 weeks beforehand, after consulting with your doctor;
• 2-3 days before the analysis, remove heavy physical activity;
• the day before the test, remove fatty and fried foods from your diet;
• For 8-12 hours then study, do not eat or drink anything other than water.

The analysis cannot be taken after physiotherapeutic procedures, as well as ultrasound, rectal, x-ray examination, and fluorography.

C protein and pregnancy

Domestic and American scientists have long been interested in the connection between the course of pregnancy and this indicator. And after numerous studies, such a connection was discovered. In the absence of inflammatory diseases in a woman, protein levels can partially predict the course of pregnancy. Doctors discovered the following patterns:

• With CRP levels above 7 mg/l, the likelihood of developing preeclampsia is more than 70%. This is a serious complication that occurs only in pregnant women, in which there is an increase in pressure, disruption of the kidney filter, damage to the nervous and cardiovascular systems;
• An increase in C-protein above 8.8 mg/l increases the risk of preterm birth;
• In case of urgent birth (which occurred on time) and an increase in the rate of more than 6.3 mg/l, there is a high risk of chorioamnionitis. This is a bacterial complication that occurs when amniotic fluid, membranes or the endometrium of the uterus are infected.

What C-reactive protein means in each specific case can be quite difficult to determine. Since it can increase due to a large number of reasons, it is necessary to exclude all these factors before forming a prognosis for a pregnant woman. However, in case of correct diagnosis, the obstetrician-gynecologist can plan the optimal management tactics for his patient.

CRP and osteoporosis

Until now, doctors continue to study what this test shows, in addition to inflammation and cardiovascular risk. Recent studies have proven the connection of C-protein with depletion of calcium reserves and pathologies of bone tissue, that is, osteoporosis. Why does this condition occur, and why is it dangerous?

The fact is that maintaining the inflammatory process requires a large amount of enzymes and microelements, including calcium ions. If it lasts long enough, the amount of these substances in the blood becomes insufficient. In this case, they begin to arrive from the depot. For calcium, bones are such a depot.

A decrease in its concentration in bone tissue leads to its increased fragility. For a person with osteoporosis, even a minor injury is enough for them to experience a complete fracture or “crack in the bone” (incomplete fracture).

At this time, doctors have not determined the exact cutoff for CRP at which the risk of bone changes increases. However, scientists from the NIIR RAMS have found that prolonged excess of this test norm is a serious risk factor for depletion of calcium reserves.

Indications

A blood test for CRP is prescribed for children when:

• suspected infectious or inflammatory disease;
• carrying out antibacterial therapy and monitoring its effectiveness;
• there is a risk of developing cardiovascular pathologies;
• recovery and complications in the postoperative period;
• transplant operations and complications such as rejection;
• autoimmune pathologies;
• control and treatment of chronic inflammatory conditions.

When and who should undergo the study?

The complexes allow you to obtain all the necessary data from a single blood sample to quickly assess the state of your body and determine whether you are at risk for developing complications of COVID-19.

It is recommended that the following categories of people undergo the study:

• Pregnant.
• People over 60 years old.
• In the presence of chronic diseases - diseases of the cardiovascular system, diabetes, respiratory diseases, chronic liver and kidney diseases, oncological pathologies, blood diseases and autoimmune disorders.
• Abuse of smoking and alcohol.
• Overweight.

Even if you do not belong to any of the risk groups and you have a mild or moderate course of coronavirus infection, but you feel a deterioration in your health and condition (usually observed on the 5-10th day of illness), it is also recommended to undergo an examination. This is necessary to assess the severity of the condition, the extent of the lesions and determine the need for hospitalization, including emergency.

Benefits of analysis

The CRP test is the most sensitive and fastest method for detecting inflammation or damage. Its level rises even before the child feels the first signs of illness.

The dynamics of CRP in the body corresponds to the stage of development of the pathological process. That is, the more active the infectious or autoimmune process in the body, the higher the protein content in the blood. Therefore, this indicator is also called acute phase protein. As inflammation decreases, so does CRP levels. This allows you to monitor the course of the disease and evaluate the effectiveness of the developed therapeutic regimen.

Another important indicator of acute inflammation in the body is the erythrocyte sedimentation rate (ESR). These indicators are often compared, and the analysis of CRP is considered more effective. This is due to the fact that reactive protein in a child’s blood increases earlier than ESR, and decreases faster. This allows you to observe a more current picture of the course of the disease and take appropriate measures in a timely manner.

Assessing the risk of heart attack using CRP

What does C-reactive protein indicate if a person does not have inflammatory or oncological diseases? Not long ago, scientists discovered the connection of this substance with the development of vascular complications. This study is especially relevant for people with cardiovascular disease or risk factors.

For people with any of these conditions, a CRP level greater than 1 mg/L indicates a risk of a vascular complication. These patients are significantly more likely to have strokes, heart attacks, kidney damage, or heart failure.

• A protein level of 1-3 mg/l indicates an average risk of developing pathologies;
• Exceeding the limit of 4 mg/l demonstrates a high risk of vascular accident.

Effect of drugs on CRP concentration

Taking acetylsalicylic acid or aspirin, even in high doses, does not affect the quantitative level of CRP. This is somewhat surprising since aspirin is known for its anti-inflammatory properties.

Patients with high cholesterol who take statins are less likely to have a heart attack because statins not only lower lipid levels but also have anti-inflammatory properties. This is very important because high CRP and low cholesterol are more dangerous than high cholesterol and low CRP. The level of CRP is also reduced by drugs from the group of fibrates and beta-blockers, but less effectively than by statins.