Cardiologists prescribe a blood test for INR for many of their patients, what it is, why it is done and what is its decoding, you can find out from this article.
What does the INR of blood show?
The INR parameter was established in accordance with international standards, which is reflected in its name. International normalized ratio - this is how the abbreviation INR stands.
This parameter characterizes blood plasma clotting. A complete analysis of the blood coagulation system (hemostasis) includes many tests, the results of which are summarized in an extensive list - a coagulogram.
INR is one of the most important parameters of the coagulogram, which makes it possible to estimate the time of blood coagulation along the external pathway (in case of tissue damage).
This characteristic is called prothrombin time (PTT) and is measured in seconds. But PTV does not give an objective idea of the true clotting rate, since this indicator depends on the type of reagent used in the research.
In different laboratories, the PTV of one person will be different.
In order to bring the results of the PTV study to a single standard, the international normalized ratio (INR) was introduced into practice.
When calculating it, the sensitivity of the reagent used in research is taken into account.
The International Index of Sensitivity (MIC), which takes into account the deviation of the sensitivity of the reagent from the standardized sample, is indicated by the manufacturer on each package and is used when calculating the INR.
The MIC is usually between 1.0 and 2.0.
The definition of MNO is as follows:
- First, there is a quotient from dividing the PTT of the blood under study by PTV, taken as the norm.
- Then this quotient is raised to a power equal to the MIH indicator.
The result obtained is free from errors and equally indicative for doctors of all countries.
INR value
Coagulation parameters are one of the most important characteristics that determine the state of health. If the blood clotting rate goes beyond normal values in the direction of increasing, then the risk of blood clots increases. Blood clots can block the vascular bed, leaving without blood supply to areas of the most important organs - the heart, brain.
Blockage of arteries with blood clots is a direct cause of life-threatening diseases:
- Heart attacks;
- Cerebral infarction;
- Pulmonary embolism (pulmonary embolism).
The risk of clogged arteries with blood clots is especially high in individuals:
- Suffering from heart defects, coronary heart disease;
- Patients with thrombosis;
- With cardiac arrhythmias - with atrial fibrillation, extrasystole;
- With a history of ischemic strokes and myocardial infarction;
- Those who have undergone prosthetics of the heart valves and coronary arteries;
- Those with sclerotic changes in the arteries - people over 50 years old.
To reduce the risk of blood clots forming in these categories of patients, they are prescribed blood thinning medications, which have to be taken daily and for life.
But when taking anticoagulants such as Warfarin, Warfarex, blood clotting can decrease so much that there will be another danger - the threat of external and internal bleeding, hemorrhagic stroke.
In order to keep blood clotting indicators in a safe range, an INR test is prescribed.
Systematic control of this parameter makes it possible to monitor the dynamics of blood thinning, and by decreasing or increasing the daily dose of the anticoagulant Warfarin, return the INR to the safe zone - from 2.0 to 3.0.
For healthy people, MHO of which is approximately equal to 1, such results would be 2-3 times higher than the norm.
But for patients with cardiovascular diseases, this degree of blood thinning is optimal. Higher MNO values may already be a risk factor for hemorrhage.
Warfarin and its analogs are indirect anticoagulants. Their action is aimed at blocking the production of clotting factors by the liver.
These drugs interfere with the metabolism of vitamin K, which is involved in the synthesis of blood clotting factors. As a result, due to a lack of vitamin K, the liver is unable to maintain high coagulability, the blood becomes thinner, and the risk of blood clots is reduced.
Direct anticoagulants (heparin, hirudin, etc.), as well as drugs based on acetylsalicylic acid (aspirin), which directly affect platelet aggregation, do not affect the INR indicator.
When taking them, as well as when taking Xarelto, there is no need for MNO control.
Who is prescribed an INR test and what are the standards?
Tests for INR can be prescribed:
- On a systematic basis. Regular testing for MHO is indicated for anyone taking indirect anticoagulants such as Warfarin.
- One-time. Such studies are carried out in preparation for surgical intervention, during pregnancy, in the diagnosis of diseases accompanied by hemostasis disorders.
- At the request of the patient. From time to time, it is recommended to take an INR test for elderly people, men whose closest relatives had early heart attacks, women after menopause, people taking direct anticoagulants (heparin, hirudin, etc.) and cardio drugs based on aspirin for prophylactic purposes.
Healthy young people who are not preparing for surgery and childbirth do not need to donate blood for INR.
For them, normal indicators are close to unity and are in the range of 0.7-1.3. You can find out what the INR rate for other categories is from the tables below.
INR norms for categories of people taking Warfarin
| Conditions requiring the use of warfarin | INR rate |
|---|---|
| Heart attack therapy | 3,0-4,5 |
| TPA therapy | 2,0-3,0 |
| Therapy for venous thrombosis | 2,0-3,0 |
| Postoperative prevention of venous thrombosis | 2,0-3,0 |
| Prevention of thromboembolism in myocardial defects | 2,0-3,0 |
| Prevention of thromboembolism in atrial fibrillation | 2,0-3,0 |
| Prevention after mitral valve replacement | 2,5-3,5 |
| After aortic valve replacement | 2,0-3,0 |
Norms for categories of persons who do not need regular monitoring of the INR
Non-compliance with the MNO norm when decoding the test result requires a doctor's consultation.
MHO deviations from the norm
If the MHO values are outside the norm, it indicates an increased risk of serious diseases and requires urgent measures to normalize it.
If the INR value in the analysis is outside the normal range in patients regularly taking Warfarin or similar indirect anticoagulants, this means that it is necessary to adjust the daily dose of the drug.
With an increase in values above 3.0, the daily dose of Warfarin should be reduced. The dose should be increased if the indicator went beyond the lower limit of the norm (less than 2.0). The decision to change the dosage must be made by the attending physician.
In people who do not take warfarin and similar drugs, deviations from the INR norm may indicate a disturbance in the functioning of the hemostasis system - excessive thickening or thinning of the blood.
If the INR indicator is increased, then there is hypocoagulation - a decrease in blood clotting.
The reasons for the decrease in the coagulation properties of blood can be:
- Genetically determined deficiency of coagulation factors;
- Disorders in the liver;
- Lack of vitamin K;
- Diseases of the gastrointestinal tract, accompanied by impaired absorption of lipids;
- Taking medications that have side effects on the hemostatic system. Such effects are caused by antibiotics, hormones, anabolic steroids and some other drugs.
If the INR analysis shows 6.0 and above, the situation becomes critical. In such cases, there is a high risk of bleeding at the slightest trauma and pathology of the vascular system. In combination with diseases of the gastrointestinal tract, accompanied by the appearance of ulcers, arterial hypertension, kidney pathology, such a high level of hypocoagulation can pose a threat to life at any moment.
Therefore, the patient is indicated for emergency hospitalization.
A low INR level may indicate improper blood sampling, as well as the fact that the tests were performed with errors. And if this is excluded, it means that blood clotting is increased - the patient has hypercoagulation.
Disturbances in the hemostasis system, leading to hypercoagulability, can be caused by internal causes or side effects from taking certain drugs.
Anticonvulsants, diuretics, hormones can give such a side effect.
The lower the INR value, the higher the likelihood of blood clots and the higher the risk of thromboembolic complications.
How often is INR control required?
Blood sampling for INR is performed from a vein. In hospital treatment, patients taking Warfarin and similar anticoagulants should donate blood for INR analysis daily. When the test results stabilize, at the decision of the doctor, it is possible to transfer to the mode of donating blood for INR once a week.
After the end of the hospital stay, the administration of indirect anticoagulants is not canceled, patients are forced to take these drugs daily for a long time, often for life.
At home, INR checks should be carried out for the first time 1 time in two decades. Depending on the patient's condition, he either visits a medical institution to donate blood for analysis, or the medical staff comes to his house.
In the future, with the stability of the results, the frequency of blood tests for INR may be reduced first to monthly, then to once every 2 months.
In addition to routine checks of INR values, there may also be a need for extraordinary measurements of this indicator.
The indications for this are:
- Such alarming symptoms as blood in urine, feces, vomit.
- Epistaxis, bleeding gums, spotting, and excessively heavy menstruation in women.
- The emergence of an acute infectious or inflammatory disease.
- The appearance of concomitant diseases requiring therapy adjustments.
- Changes in living conditions - physical activity, nutrition, regimen.
- Flights, trips to another climatic zone.
In order for the prevention of complications associated with disturbances in the functioning of the hemostasis system to be effective, strict regular monitoring of the INR value is necessary, as well as its extraordinary check in case of changes in the patient's health status and lifestyle, followed by adjusting the daily dose of Warfarin.
Video: Blood test rates
A blood test is the beginning of diagnostics and a mandatory component of medical examinations. Seeing the direction, patients ask themselves: what is INR blood test? A typical laboratory study that allows you to accurately determine the functioning of the hemostatic system. The INR analysis allows you to determine the blood plasma coagulation index. Unlike other research methods, the INR blood test is recognized by international experts as the most accurate.
Laboratory research
INR in a blood test - what is it? The ability of blood to maintain a liquid state ensures its normal circulation through the circulatory system. The ability to coagulate protects the body from possible bleeding in case of injuries and injuries of varying severity. This process is supported by a complex protein called prothrombin. Protein formation occurs in the liver with the participation of vitamin K. INR blood test is an index that reflects the rate of functioning of the hemostasis system.
The INR indicator is calculated as the ratio of the prothrombin time in the test sample to the prothrombin time of a healthy person. For this, a special formula is used. The obtained result is corrected relative to the sensitivity index of the reagent used in the analysis. The determination of INR is regulated by the relevant standards and is a process approved by the World Health Organization.
The results of analysis of the same patient in different laboratories will be identical.
The INR level indicates the risk of blood clots or the threat of bleeding in patients, which means that abnormalities in the analysis are an early diagnosis of serious diseases. It is most often indicated as a control over the effectiveness of treatment while taking direct or indirect anticoagulants. During the patient's stay in the hospital, blood biochemistry at the INR is carried out daily, over time, the study is carried out weekly, monthly, or less often as directed by the doctor.
When to see a doctor
It is not only patients taking blood thinners that should know what an INR is in blood and be regularly examined. The functioning of the circulatory system depends on the general health of the person and environmental factors.
Often, unforeseen circumstances and stress can change the usual way of life and serve as an excuse for a visit to the doctor and a referral for analysis:
- Changes and deterioration in diet, including low vitamin K in the diet
- Change of climatic zone, long distance travel
- Unusual work schedule (changes in rest and sleep patterns or additional physical activity)
- Drug treatment of diseases with drugs that can affect blood clotting (diuretics, anticonvulsants, antibiotics, etc.)
- Physical injuries of varying severity, tissue necrosis
- Exacerbation of chronic liver and heart disease
- Prolonged colds or infections
- Detection of bloody discharge in sputum, vomit, urine, etc.
- Frequent nosebleeds and bleeding of the gums, which indicate impaired coagulation.
- Unusually heavy and prolonged periods in women
- Painful sensations and swelling in the joints when taking anticoagulants
How to get tested
Donate blood for biochemical analysis International normalized ratio or INR can be in any laboratory in the direction of the attending physician. If the necessary equipment is available, a local therapist can conduct a study in his office. For patients who need to measure INR values quite often, there are special portable devices. The device allows you to do an analysis at home and quickly get the result.
Blood sampling under laboratory conditions is carried out from a vein. As a rule, it is recommended to take the test in the morning, since food cannot be eaten 8-12 hours before. Alcohol, fatty and smoked foods are excluded for 24 hours. On the day of the analysis, one should not smoke, drink tea or coffee; it is allowed to drink mineral water.
Self-measurement of INR using a portable device is a simple process that is understandable for every patient. For the test, capillary blood is used, that is, a sample is taken from a finger. The entire INR test kit can be purchased at a pharmacy or online store. For the test, you will need: a special portable device equipped with a display, a disposable sterile scarifier in individual packaging, a test strip and an antibacterial napkin or cotton wool with alcohol.
The skin of the finger is wiped with an antibacterial napkin and pierced with a scarifier. Blood is applied to a test strip and placed in the meter. After a short time, the analysis result will appear on the device screen. The test result should be reported to the attending physician. If necessary, a home test is confirmed by a laboratory analysis of venous blood.
Research results
The INR value may differ from the accepted norm, depending on external factors. Therefore, the interpretation of this value and the control of the INR is carried out by qualified specialists. The index for the INR of a healthy person, regardless of gender, should be as close to one as possible.
Depending on the diseases and drugs taken, an appropriate rate of blood plasma clotting of the patient is established:
- For healthy men and women, 0.7-1.3 is the norm
- Before surgery, in order to avoid severe bleeding and thrombosis, the recommended clotting index is 0.8-1.25
- In pregnant women, the INR should be in the range of 0.8-1.25
- When using heparin and other direct anticoagulants, the INR indicator should be in the range of 0.8-1.2
- When using neodikumarin, phenylin or other indirect anticoagulants, the norm is 2.0-3.0.
- With pathological changes in the heart valves, the norm is an indicator within 2-3 units of measurement.
- In patients with antiphospholipid syndrome, the coagulation index ranges from 2.5 to 3.5
- In case of vascular diseases, it is necessary to constantly monitor the INR, the noma is 3-4.5
Analysis deviations
The patient can influence the test result by ignoring the recommendations of the doctor and laboratory assistant before donating blood. For example, eating a large meal before going to the lab will result in a false INR result. In this case, the analysis is invalidated, and the blood test is re-assigned. Sometimes technical factors lead to the distortion of the analysis result.
Insufficient mixing of the blood with the reagent inside the tube can lead to clot formation and sample deterioration.
If, when taking venous blood, capillary blood and tissue thromboplastin get into the material for research, the result will be unreliable. Laboratory and processing errors include improper or too long storage of the sample. As a rule, health workers immediately identify a clearly erroneous test result, and the doctor orders a second test.
If a significant deviation of the INR indicator from the norm is found, one should not make hasty conclusions. When decoding the results of the analysis, the attending physician takes into account all the factors and makes a well-founded conclusion. Additional research or medication may be needed.
Modern medicine and international organizations recognize the INR blood test and that it is an effective and stable method for studying the hemostasis process. The result of the study allows you to evaluate the coagulation and anticoagulation systems of the blood. With normal functioning of the circulatory system, the INR is 0.7-1.3, there is no risk of bleeding and thrombosis. To find out where to get tested for INR and what it is, it is enough to contact your local therapist.
In contact with
What is the norm of INR in blood in women is considered normal? A test or analysis for an international normalized attitude today is often prescribed to patients who are treated with drugs that can destroy blood clots from which blood clots develop. The purpose of this analysis is explained by the fact that treatment with anticoagulant drugs requires constant medical supervision from the patient. Such a biochemical analysis involves a blood test for the speed of clotting and the appearance of a clot. In order to find out the INR norms, you need to get acquainted in more detail with the test, the indications for its conduct and the methods of execution.
Each person has a coagulation and anticoagulant system, the normalized work of which ensures the "correct" density of the blood flow, while anticoagulant mechanisms are responsible for its fluid. If a patient experiences an imbalance between these two systems, then he has a risk of bleeding or blood clots (these are dangerous blood clots that clog blood vessels).
Prothrombin is responsible for the functionality and general condition of the coagulation system - this is a specific protein that is considered the most important indicator during a coagulogram.
Also, prothrombin, produced by the liver thanks to vitamin K, is also called factor II in the process of blood clotting. Prothrombin is considered a precursor of thrombin, therefore, after the analysis, its results can be understandable to the doctor, and he can easily assess the state of blood coagulation, as well as the possibility of the appearance of blood clots in the patient's body or the development of bleeding.
Determination of the concentration of this substance in a patient is carried out in the following ways:- prothrombin time (PTR);
- prothrombin index (PTI);
- the level of the substance on the Quick scale;
- INR of blood.
As a rule, INR is most often prescribed to patients, since such a study most thoroughly and accurately reflects the state of coagulation of a drop of blood and the general condition of the patient's body.
The norms of this important laboratory test are a reflection of the patient's PTT values to the PTT results in a healthy person. Due to the fact that a special table was developed that reflects the standards of the norm p 
rothrombin in the body, doctors manage to combine the results of various studies to a generally accepted indicator. This INR blood test has received widespread approval from various medical organizations. After all, it invariably gives the same analysis result, even if it was carried out in different clinical laboratories.
Thanks to the introduction of standards that subdivide the INR indicator, it is possible to effectively control the result of medical therapy in patients for whom the doctor prescribes a certain group of drugs that promote blood thinning - Finilin, Warfarin and Sinkumar. If necessary, which will be indicated by a change in the results of the INR, the norms of which will be different, it will be possible to take timely measures to stop the problem.
Anticoagulants today are prescribed to patients who are endowed with the risk of blood clots in the body, which is observed in various pathologies:- heart attack;
- thrombosis;
- pulmonary embolism;
- thromboembolic complication resulting from the development of coronary insufficiency in the body;
- thrombophlebitis;
- heart disease, etc.
If the interpretation of the INR results shows an increase, this indicates a patient's predisposition to bleeding, which gives the doctor a reason to reduce the dose of coagulants. If the test indicators are reduced, then the patient is diagnosed with the risk of developing blood clots in the body. This suggests that drugs that can thin the blood are endowed with low effectiveness, so the doctor increases the dose of drugs.
It is difficult for a person who does not delve into the abbreviation INR to make out this combination of letters. Moreover, many believe that such an analysis after decoding the first letters will not give anyone any explanation. In fact, an INR blood test is a specific blood test for the amount of prothrombin in the body. As mentioned above, prothrombin is a complex protein. In addition, this element allows you to assess how the patient's blood coagulation process proceeds. Thanks to this analysis, doctors assess the state of the liver and gastrointestinal tract, and also identify pathological processes in these organs, if any. A laboratory test for the determination of prothrombin in humans is considered the most necessary study that is aimed at assessing coagulation.
- PTV - the period during which a drop of blood coagulates - this phenomenon is measured in seconds;
- determination of prothrombin according to Quick is the ratio of the activity of an element, which is measured as a percentage;
- PTI is the ratio of PTV of a sick person in relation to a healthy one;
- INR is a comparison of PTT in humans to the prothrombin period.
The indices of PTI are normally about 80-100 units in a person who does not suffer from diseases of internal organs. If the patient takes Warfarin during the test, a medicinal composition that can reduce blood clotting, then the PTI values are reduced to 24-42.
At the moment, several methods have been developed for determining the PTI indicators, but they do not give a reliable result, especially if the analyzes were carried out in different diagnostic centers.
Most doctors prescribe an INR to patients, since such blood biochemistry shows the most correct and truthful result, regardless of the laboratory conditions where it is carried out.
In adults, the INR rate is approximately 0.7-1.3, but it often varies within a "radius" of 0.85-1.25. If the patient takes anticoagulants as indicated by the doctor, the INR level after the tests is 2.0 or 3.0 units.
If people do not take medicinal formulations aimed at thinning the blood flow, then the disturbed INR indicators up or down indicate that the patient has serious pathological diseases.
The formation of elevated INR values, which are more than 1, indicates the presence of the following diseases:- Pathology and disruption of the liver.
- Lack of trace elements, as well as vitamin K in the body.
- Congenital or acquired pathologies of the coagulation system.
- The appearance of side signs as a result of taking antibiotics or anti-gout drugs.
- Impaired absorption of fats from food into the intestinal wall.
A condition in which increased INR values and deterioration of coagulability occur is called hypocoagulation, which threatens the development of external or internal hemorrhages in the patient. In this case, the first type of bleeding often occurs even after minimal damage to the skin (scratch, open wound, and so on). The causes of internal bleeding (uterine, cavity, stomach, and so on) can be any diseases and processes in the human body (for example, menstruation).
Especially dangerous, critical, can be called INR values exceeding 6.0. This threatens with serious problems in diseases of the vascular and urinary system, inflammation and lesions of the gastrointestinal tract with ulcers, as well as hypertension. In these cases, the patient needs prompt hospitalization and effective treatment.
It is also worth remembering that if a change in the INR results in a larger direction is observed in people taking anticoagulants as treatment, this indicates the need to adjust the dose of these drugs.
With a decrease in INR values in a patient, the following pathological conditions may develop:- an increase in the amount of antithrombin in the body;
- jumps in hematocrit up and down;
- side effects on the woman's body of diuretic medicinal compositions.
Collection of blood from the patient for the study is done from a catheter that was previously installed in the central vein.
A decrease in INR parameters is called hypercoagulation, in which patients have a high risk of serious complications such as pulmonary embolism and thrombosis.
Prescribing a biochemical blood test for an INR to a patient is prescribed according to specific indications.
- When examining a patient before the upcoming operation, the norm is values close to 1.
- Taking medications intended to thin the blood - INR values vary in the range of 2.0-3.0.
- In PE therapy, values from 2.0 to 3.0 are the norm.
- After the mitral heart valve replacement with a mechanical implant is done, the norm is 2.5-3.5.
- If a heart defect is detected in a patient, the results of the tests performed should vary in the range of 2.0-3.0 units.
A blood test for people who are taking anticoagulant drugs designed to thin the blood flow should be done after a specific amount of time, as prescribed by the doctor.
At the very beginning of the disease, while the patient is still in the hospital, such INR tests are performed daily. Later, the patient's INR study is carried out once a week, if the indicators do not go beyond the normal range, the frequency of blood tests will decrease to 1 time per month.
The reason for the discharge of an extraordinary INR study is some changes in the patient's rhythm of life, as well as symptoms of hypocoagulation:
- bleeding gums, manifested daily;
- regular nosebleeds;
- a long course of colds or other pathologies;
- climate change in the patient;
- the presence of blood droplets in the urine;
- bleeding that does not go away from wounds, scratches and cuts;
- adherence to a diet;
- the occurrence of seals and swelling in the joints;
- unreasonable occurrence of hematomas;
- blood in the stool;
- lumps of blood in sputum or when vomiting occurs.
Where is the INR test carried out?
To donate blood and get INR results, you need to take a doctor's referral for tests that are performed:- in the clinic;
- laboratories;
- at home.
In addition, this test is often carried out in the doctor's office, however, if he has all the necessary equipment. You can independently make an INR test using a special portable device.
Home testing for INR is the most convenient option for many patients, since they do not need to constantly visit the clinic.
Carrying out this test involves the use of blood from a finger (in this case, a man and a woman should know how to properly prepare for donating blood). To get it, doctors use a scarifier to make a painless hole in the skin. After that, special test strips are inserted into the device for determining the INR, where the doctor applies a drop of blood. After a while, the INR values appear on the scarifier display.
According to the advice and recommendations of the WHO, an INR study must be prescribed for any method of treatment that requires regular monitoring of the level of blood clotting. After all, this analysis most accurately reflects the functional state of blood coagulation in the patient and quickly gives a reliable result.
Patients who are forced to constantly take drugs to thin the blood are required to control its coagulation abilities. This is necessary not only to assess the effectiveness of treatment, but also allows you to select an adequate dose of funds. In the same way, a person can be protected from an overdose of anticoagulants, preventing the development of corresponding complications against this background. One of the modern methods of such control is INR (International Normalized Ratio).
The essence of the study of the indicator
The blood test, which determines the international normalized ratio, consists of several stages. In general, the INR indicator is not an actual value that is obtained from a blood test. It can only be found out through mathematical calculations. The initial figures are:
- The value of the prothrombin time of the subject. This indicator refers to the components of the coagulogram (detailed analysis of blood coagulation). For this, in fact, the patient's blood is taken;
- Average normal prothrombin time. It is 11-16 seconds;
- International Thromboplastin Sensitivity Index (MIC). Thromboplastin is a reagent that a specific laboratory uses. Such reagents are manufactured by many different companies. Therefore, in the passport of a specific thromboplastin, the amount of its purification and sensitivity (MIC) is indicated.
The INR indicator can be obtained by raising the ratio of the patient's prothrombin time to its average normal value to a degree equal to the MIC of the thromboplastin used.
What is it for
It would seem, why carry out such complex calculations when there are actual indicators of blood clotting. The point is that not everything is so simple. Features are as follows:
- INR is an indicator purely for assessing the effectiveness and correctness of treatment with indirect anticoagulants (warfarin, syncumar, warfarex). The peculiarity of their action is that they affect only some factors of blood coagulation. None of the methods can so accurately show the state of this particular link of the blood coagulation system;
- Different degrees of purification and sensitivity of thromboplastin used by laboratories;
- Standardized doses of indirect anticoagulants for certain types of thrombotic diseases worldwide.
What does this give in the end? Experts get a true indicator of blood plasma clotting. At the same time, any errors, external influences and links of hemostasis that can affect its value are excluded.
Wherever the study was conducted, the resulting indicator would be identical and would be equally evaluated in any medical institution in the world. Thus, it is possible to select the required dose of anticoagulants and control the treatment.
To study INR, blood from a vein is needed
Technique and frequency of blood sampling
A blood test to determine the INR is carried out for persons who are on a constant intake of indirect anticoagulants (syncumar, warfarin), at intervals of two to three weeks. Sometimes it becomes necessary to conduct research more often. It all depends on the duration of treatment, the patient's condition and the specific type of pathology. Patients with a matched dose of anticoagulant and an appropriate INR can be monitored once a month.
It is possible to obtain blood for research only by taking it from a peripheral vein. The sampling technique does not differ from standard analyzes. Compliance with the fasting research rule is mandatory.
Interpretation of findings and norms
The general rule that is used when assessing INR during therapy with indirect anticoagulants is as follows: the higher the INR, the more liquid the blood is.
The obtained INR indicator can be interpreted as follows:
- INR corresponds to normal values - anticoagulant treatment is carried out correctly. The dose is adequate. It is recommended to continue taking them in the same mode;
- INR is higher than the established norms for a specific pathology. This indicates an overdose of indirect anticoagulants, which threatens with complications in the form of bleeding. The dose should be reduced;
- INR below normal values - treatment with anticoagulants does not bring the proper effect of blood thinning, which threatens the development of vascular thrombosis. The dose of the drug should be increased.
| Recommended norms of INR | Deciphering the conditions in which you need to strive for the specified indicator |
| 0,8 - 1,15 | INR in persons not under the influence of anticoagulants (normal) |
| 1,5-2 | Prevention of blood clots in the heart in all types of atrial fibrillation |
| 2,0 - 3,0 |
|
| 3,0 -4,0 | Treatment of single and multiple thromboembolic lesions of the peripheral main arteries; |
| 3 - 4,5 | Prevention of thrombosis and thromboembolism after operations with the introduction of any vascular and heart prostheses |
Compliance with the rules for taking anticoagulants under INR control will save you from unnecessary expenses for excessive doses of expensive drugs, inadequate treatment and severe complications.
If a person suffers from vascular diseases and is prescribed a long-term intake of drugs that promote blood thinning, he must monitor its coagulation and take a biomaterial for analysis every 15-20 days.
Physicians will be able to assess how effective the prescribed therapy regimen is and, if necessary, adjust the dosage of drugs. To identify the value, a blood test for INR is assigned.
How the abbreviation stands
When issuing a form with the results of the analysis, patients do not understand what it is - INR. The definition of the term is as follows: international normalized ratio. The index is not actual, it is calculated in four stages.
It is calculated in a mathematical way, for this you need to know the following data:
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- The value of the prothrombotic period. The patient needs to pass the biomaterial for analysis, after which a coagulogram is performed, the blood coagulation index is determined.
- Average value . In a healthy person, the value ranges from 11 to 16 seconds.
- International Thromboplastin Sensitivity Index. The laboratory component is manufactured by various pharmaceutical companies.
- INR. To determine the value, the ratio of the prothrombin period to the average normal value is raised to the power of the ISI coefficient (equated to MIH).
It takes 5-8 hours to obtain information in the laboratory and calculate the results. When tested in a public hospital, the result is announced after a week.
What data does a blood test for INR show?
Why do laboratories carry out such long and difficult calculations when the actual value of blood clotting exists? Doctors assure that the analysis is of the utmost importance:
- The indicator is needed to assess the effectiveness of the prescribed therapy. The study is prescribed if indirect anticoagulants are prescribed (Warfarin, Sinkumar). Medicines of this pharmaceutical group affect coagulation factors, therefore, other analyzes and tests will not give a reliable picture of the state of these functions of the coagulation system.
- The test result varies depending on the susceptibility of thromboplastin used in laboratories.
- Doctors evaluate how effective the prescribed dose of drugs is for a specific disease of the vascular system.
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Taken together, blood clotting indices give physicians the opportunity to determine the real plasma clotting index. The technique excludes the probability of an error in the final result, external factors do not have side effects on the study.
The effectiveness of the method is confirmed by the fact that the result of the analysis is equally assessed in any clinic, regardless of the country and city. The study is necessary, with the help of it you can choose the optimal dosage of drugs, which makes it possible to control the treatment.
Blood sampling for research is carried out from a patient treated with indirect anticoagulants. The analysis is carried out every 15 days, if necessary, the study is prescribed more often. The frequency depends on the condition and well-being of the person, the type and stage of development of the disease.
When a study is prescribed
The analysis for the level of INR in the blood does not belong to the standard (like biochemistry, general), it is carried out with specific indications:
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- The person is prescribed surgical intervention. Preparation for surgery includes this analysis, the MHO level should be at least 0.85, but not exceed 1.25.
- Carrying a child (for the 1st, 2nd, 3rd trimester).
- Treatment of deep vein thrombosis with anticoagulants, venotonics.
- Diagnostics of the antiphospholipid syndrome.
- Prevention of thromboembolism and vascular pathologies.
- Recovery and rehabilitation after prosthetic heart valves.
The results are deciphered by the attending physician, the physician is repelled by the index norm, the condition of a particular patient. When taking drugs prescribed for the treatment of vascular pathologies, the value of the norm will differ from the standard.
Preparation and analysis
The International Normalized Relationship Index is identified in different ways. You need to donate blood at a medical facility or diagnostic center. The main thing is the availability of the necessary equipment. The result is announced in 4-6 hours. To obtain a referral for analysis, a visit to a therapist is required.
Doctors warn patients: to get a reliable result, you will have to adhere to the rules, external factors affect the blood clotting rate. If you ignore the preparation, an unreliable result will appear.
- within 3 days before the analysis, the use of alcoholic beverages is prohibited;
- 24 hours before the delivery of the biomaterial, it is recommended to abandon foods saturated with fats, spicy and salty foods;
- it is forbidden to take medicines of any pharmaceutical category before the event;
- sampling of biomaterial is not carried out during menstruation;
- the test is carried out before lunch on an empty stomach.
International norm of INR
An increased indicator directly affects the consistency of the plasma. By international standards, the INR index should be within one. It deviates from the accepted value for internal pathologies, inappropriate dosage of drugs:
- The index is increased. It is required to adjust the dosage of the prescribed medications, taking into account the specific pathology. Otherwise, there is a possibility of complications (bleeding).
- Downgraded index. It manifests itself when the treatment is ineffective and the blood does not thin. If the dosage of anticoagulants is not increased, blood clots will form in the patient, and the structure of the vessels will change.
Adult norm
In women and men, the INR rate varies from 0.7 to 1.3. If the test showed that the indicator does not move away from these values, the person is healthy, does not suffer from pathological processes. Experts say that in adult men, the norm does not differ from that of women.
The only difference is that special control over blood clotting is carried out during the gestation of a child, since the woman's body is undergoing tremendous changes. During pregnancy, plasma is donated every trimester.
Expectant mothers need to take into account that the index can be increased, which is not considered a deviation from the norm. A danger to the fetus arises if the value is more than 4, the possibility of miscarriage or premature birth cannot be ruled out.
To make an accurate diagnosis, a woman is prescribed a second test, after decoding the result, doctors prescribe a competent treatment.
Norm for a child
In children, after birth, the INR indicator is kept within unity; as it develops and grows, the index is equated to adult values.
Decoding the results
A table of normal values for both sexes and different ages is available in the doctor's office issuing the results form. According to it, they are guided by how much the results deviate up or down. The data obtained depend on the presence of diseases, medication intake.
To correctly decipher the result, take into account all factors in the aggregate. More often, the test is prescribed for the reasons that are indicated in the form:
- Treatment of chronic atrial fibrillation. When warfarin is prescribed as the main medication, the INR rate varies from 2 to 3.
- Therapy for pulmonary thromboembolism. The index ranges from 2-3.
- Heart disease. If violated, the value will be about 3.
- Vascular diseases. The result is in the range of 3-4.5.
- Thrombosis treatment. The indicator ranges from 2 to 3.
Deviation of INR from the norm
If the analysis shows that the mno index has risen above the norm or deviated to the lower side, and the person does not take indirect anticoagulants to combat thrombosis, this is a sign of a pathological process.
Increased INR value
When the result shows a high value, blood clotting is reduced. More often, pathology develops due to such factors:
- congenital deficiency of substances and compounds responsible for blood clotting;
- lack of vitamin K;
- pathological changes in the liver;
- dysfunction of the gastrointestinal tract;
- manifestation of side effects due to prolonged use of medications.
A person suffering from a stomach ulcer, when diagnosed with an elevated index, requires immediate hospitalization.
Reduced value
It occurs when the biomaterial is improperly removed or the device malfunctions. If the blood sampling was carried out correctly and the equipment is in good order, the lowered index indicates the presence of pathologies:
- excessive content of antithrombin;
- thrombosis of the lower extremities and thromboembolic complications (manifested during pregnancy);
- the appearance of a side effect from taking anticonvulsants.
If the INR indicator decreases while taking Warfarin, the prescribed dose is not suitable for the patient, immediate correction is necessary.
How to level up
Depending on the patient's condition and his diseases with a lowered index, doctors prescribe an increase in the dosage of Warfarin, they advise to adjust the index by changing the diet.
It is recommended to avoid foods containing vitamin K, as this substance helps to lower the level. The largest amount is found in liver, green and black tea, chicory, Brussels sprouts, spinach, lettuce. It is necessary to limit the consumption of fresh cucumbers and apples, asparagus, mayonnaise.
If Warfarin is prescribed, products will help to increase the indicator in the shortest possible time: garlic, ginseng, red currants, fish oil. When combined with the drug, these products have a beneficial effect.
How to lower the INR index
When the INR level exceeds the normal value, it is required to reduce the dose of prescribed drugs. The patient is assigned a diet based on:
- oatmeal, buckwheat;
- wholemeal pasta;
- sunflower oil;
- baked and boiled potatoes;
- lean river, sea fish;
- fermented baked milk and kefir;
- crackers;
- eggs;
- dried fruit compotes.
What happens if you do not fight the violation
If the measurement showed that the INR level deviates from the norm, the patient needs an immediate correction of the dosage of drugs, a change in diet, otherwise deviations will appear:
- the formation of pathogenic blood clots in the vessels;
- pulmonary embolism;
- progression of liver disease;
- intestinal dysfunction.
If the index is above 5, there is a risk of developing internal and external bleeding, which cannot be stopped without professional help. When the indicator is close to the critical value, urgent hospitalization is required.
If a person does not suffer from chronic diseases, an INR test is not required. But experts advise to undergo a study every 1.5-2 years.
Such a preventive measure will help identify the presence of certain pathologies and prevent their progression, which will preserve the patient's health and help avoid unwanted complications.
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