From this article you will learn:
- Everything you wanted to know about biochemical blood test
- Preparing for a biochemical blood test
- Biochemical blood test indicators
- Interpretation of biochemical blood test
Many people in the modern world are concerned about the decline in quality of life. Environmental problems, unhealthy diets and unhealthy lifestyles do not go unnoticed. Under such conditions, the occurrence of diseases is quite natural. When visiting a doctor, people want to be informed about the condition of their body and about those pathologies that may already exist and require immediate treatment. It is at this stage that a biochemical blood test is performed.
This study is prescribed at the first stage of diagnosing any disease. Biochemistry will tell you in time about the increased risk of developing cardiovascular diseases, about problems with the kidneys and liver, about malfunctions of the endocrine glands, and even about the beginning of oncological processes. The importance of this research can hardly be overestimated, but despite its simplicity, many do not dare to do it. In the article we will dispel all fears and doubts, talk about the features of the analysis and reveal the secret of how to pass it so that the result is as reliable as possible.
Everything you wanted to know about biochemical blood test
A standard biochemical blood test allows you to obtain information on the following indicators:
- carbohydrates (fructosamine, glucose);
- enzymes (ALT, AST, alkaline phosphatase, gamma GT);
- pigment substances (bilirubin);
- proteins (total and albumin);
- lipid profile (LDL, total cholesterol, triglycerides);
- nitrogenous compounds (uric acid, urea, creatinine);
- serum iron;
- electrolytes (K, Na, Cl);
- C-reactive protein.
1. Why donate blood for biochemistry.
A biochemical blood test is given to find out:
- how liver cells function;
- how the kidneys cope with urine filtration;
- is there an inflammatory process and how active is it;
- whether pancreatic hormones and digestive enzymes are formed;
- Is absorption good in the intestines?
- is there a risk of diabetes, atherosclerosis and angina;
- is there a need for minerals;
- degree of myocardial damage during infarction.
2. Indications for the study.
When a person seeks help from a doctor with certain symptoms, he is required to undergo a biochemical blood test. Indications for its implementation are:
- Problems associated with the female reproductive system, for example, menstrual irregularities, its disruptions, the cause of which is unclear, infertility, inflammatory processes in the appendages and uterus, ovarian cysts, fibroids, endometriosis.
- Diseases of the gastrointestinal tract and liver (gastritis, pancreatitis, stomach ulcers, enteritis, cholecystitis, gastroenteritis).
- Pathologies of the endocrine system (dysfunction of the adrenal cortex, diabetes mellitus, hyper- and hypothyroidism, suspicion of a tumor of the pituitary gland and hypothalamus, obesity).
- Problems related to the heart and blood vessels (stroke, heart attack, cerebral ischemia, hypercholesterolemia, coronary heart disease).
- Possible liver and kidney failure (to identify and treat the disease).
- Oncology.
- Pathologies associated with the musculoskeletal system of an inflammatory and degenerative nature (osteoporosis, arthritis, arthrosis).
Often, in order to make an accurate diagnosis of a patient, it is enough to conduct a biochemical blood test. However, in some cases it is necessary to resort to additional research methods, depending on the individual characteristics of the person and the course of the disease.
3. Types of biochemical blood tests.
To assess the condition of the patient’s body, the doctor, in addition to the minimal and extended panel, can select indicators that characterize the performance of a particular organ or system. Thus, a biochemical blood test can be of the following types:
- Liver tests, including indicators such as enzymes (alkaline phosphatase, ALT, AST, LDH, GGT), direct and total bilirubin.
- Kidney tests (urea, creatinine, total protein).
- Lipidogram (lipoprotein complexes, cholesterol, triglycerides).
- Acute phase inflammation (fibrinogen, C-reactive protein).
Why does jaundice appear?
There are several mechanisms for the occurrence of jaundice.
Cause of jaundice | What's happening? |
Increased breakdown of hemoglobin | Due to the too active production of indirect bilirubin, the liver simply cannot cope with its processing and excretion |
Liver diseases | The amount of bilirubin produced does not exceed the norm, but the affected liver cells are not able to fully function and cope with their work |
Impaired flow of bile | Instead of entering the intestines, bile accumulates in the liver and provokes its destruction. Bilirubin then enters the blood again. |
Jaundice is an indication for a biochemical blood test to determine the level of bilirubin in the blood. These indications also include liver tumors and cirrhosis, hepatitis, and hemolytic anemia.
Preparing for a biochemical blood test
In order for the results of a biochemical blood test to be as informative as possible, you should prepare for its delivery. To do this, you need to take into account a few simple requirements.
To carry out the analysis, you need about 5 ml of venous blood, distributed over several tubes. It is worth noting that the indicators can be affected by a variety of factors, ranging from the food that the patient ate on the eve of the test and the water he drank, to physical activity, emotional arousal, and also taking certain medications.
That is why before visiting the laboratory you must adhere to the following rules:
- do not eat 10–12 hours before donating blood for analysis;
- you should not drink strong tea and coffee in the second half of the day preceding the study;
- Eliminate fatty, spicy, fried foods, alcoholic drinks, etc. from the diet for two to three days.
- give up procedures such as a hot bath, sauna or steam bath, as well as excessive physical activity one day before;
- Before donating blood on the same day, you cannot take medications, perform various manipulations and medical procedures (injections, intravenous administration of drugs, fluorography, dental treatment);
- on the day of collection, you need to avoid morning jogging, physical exercise, and long walks (including to the laboratory), otherwise the results may be unreliable;
- avoid nervous tension, stress, emotional overexcitation (this can also affect performance);
- before donating blood, you need to sit for 10 minutes and calm down, restore your heartbeat and breathing;
- if the blood is tested for glucose to diagnose diabetes, then in the morning you should not drink any drinks, not even water, brush your teeth (especially with toothpaste), or chew gum, since taste buds activate the activity of the pancreas and the production of insulin;
- a day before the analysis, stop taking hormonal, diuretic, thromboral-absorbing, antibacterial medications, as well as drugs that affect blood viscosity;
- to determine the amount of cholesterol in the blood while taking statins, you should stop the course 10–14 days before the test (only in consultation with your doctor);
- if a repeat test is necessary, blood donation should take place under exactly the same conditions at the same time and place (ideally, it is necessary to take an identical route from home to the laboratory on foot or by transport).
Alpha amylase
This enzyme is special. It breaks down complex carbohydrates into simpler compounds. Alpha amylase is concentrated in the salivary glands and pancreas. When examining blood, the doctor will definitely pay attention to the decrease and increase in the level of this enzyme.
Alpha-amylase exceeds the normal level in hepatitis, pancreatic cancer, pancreatitis, mumps, and renal failure.
A decrease in the level of the enzyme is observed with alcoholism, myocardial infarction, toxicosis during pregnancy, thyrotoxicosis, pancreatic necrosis, and taking steroid drugs.
Biochemical blood test indicators
It is not scary if the indicators obtained as a result of a biochemical blood test differ in each clinic, since there is a range of normal values. The final word regarding whether the indicators are considered low, high or acceptable always remains with the attending physician, who makes conclusions in accordance with the medical history.
Table of normal indicators for biochemical blood tests:
If we talk about what is included in a detailed biochemical blood test, then these are indicators both for preventive studies carried out periodically, and for identifying serious diseases and disorders. However, in the first case, there is no point in detailed biochemistry, as well as in the presence of certain symptoms and specific complaints. Additional indicators are included in the analysis depending on the health status of the person who consults the doctor.
The fact is that if a patient complains of extreme thirst, then first of all the amount of glucose in the blood will be checked. If the problem is high blood pressure, attention is paid to the lipid spectrum. In case of anemia, they look at transferrin, iron, ferritin, TIBC, that is, the iron-binding capacity of serum. If the doctor suspects problems with the liver, as well as hepatitis, then indicators such as bilirubin, liver enzymes (ALT, AST and alkaline phosphatase) are assessed.
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How do the quantitative indicators of urea, creatine, and residual nitrogen change?
Like all other indicators, these three can also vary up or down. Such results are possible due to the destruction of body tissues, as a result of which protein increases, or due to incomplete kidney function. In some cases, these indicators increase in older people, which is the norm.
Among these indicators, the quantitative increase in creatine and urea is very important. The higher their values, the more obvious the kidney pathology.
Decoding the biochemical blood test
1. Indicators of total protein and fractions.
In the results of biochemical analysis and clinical research, the amount of total protein and proteins, that is, its fractions, is necessarily assessed.
At least 160 different proteins can be found in the blood, which are combined into three protein fractions (according to functions and composition): globulins (4 types), albumins, fibrinogens.
Without proteins, the body cannot function properly. However, their content in a biochemical blood test is below normal, indicating that the liver, which is responsible for the production of proteins, is not capable of synthesizing them. This, in turn, may indicate diseases associated with this organ. In addition, such indicators can cause:
- low protein diet (fasting, vegetarianism, diet with limited protein foods);
- parasitosis, in particular helminthic infestations;
- blood loss caused by heavy menstruation, external or internal bleeding due to injury or illness;
- extensive skin burns;
- kidney disease with excessive release of proteins during urination, proteinuria of the gestational period, etc.;
- hepatitis, cirrhosis with reduced protein synthesis;
- long-term use of glucocorticosteroids;
- development of malignant tumors of the stomach and bladder;
- poor absorption of nutrients in the intestine with colitis, enteritis, celiac disease and pancreatitis;
- ascites, pericarditis and ascites accompanied by plasma accumulation.
To diagnose diseases associated with parenchymal organs in a patient, identify rheumatism, and also if there are signs of the development of neoplasms, the doctor pays attention to the concentration of albumin in the blood. It can also be used to judge the effect of hormonal drugs and the consequences of fasting and dieting on the body.
If the indicators of the protein fraction of albumin in a biochemical blood test in an adult are below normal, this may indicate the development of nephrotic syndrome, renal or liver failure, the presence of tumors of the digestive system, cardiospasm, processes of tissue breakdown, paracentesis, lymphorrhea, exhaustion, etc.
2. Nitrogen metabolism.
When conducting a basic biochemical blood test, as a rule, creatinine and urea are examined, and other components related to low molecular weight nitrogenous substances (residual nitrogen, uric acid, ammonia) are added if it is necessary to verify or refute the presence of other pathologies and disorders.
The functioning of living organisms is always accompanied by the breakdown of cells and tissues, during which the production of nitrogenous compounds occurs. When, according to the results of the study, a deviation from the norm is observed, we can talk about disturbances in the functioning of the liver (nitrogen compounds are synthesized during the breakdown process), kidneys (accumulation due to poor filtration and incorrect excretion in the urine), and increased breakdown of proteins caused by various factors.
Connection name | What does exceeding the norm indicate? |
Urea | Hepatic or renal failure, hypertension, exposure to toxic substances, compartment syndrome |
Creatinine | Severe lesions and diseases of parenchymal organs, impaired functioning of the adrenal glands, tumors, diabetes mellitus |
Uric acid | Leukemia, gouty syndrome, anemia with vitamin B12 deficiency, dermatitis, poisoning, acute infectious process, liver disease |
If there is a decrease in nitrogen compounds in the blood, this may indicate liver failure, polyurine, hypothyroidism, prolonged fasting, or poor metabolism. In addition, such indicators can occur after hemodialysis and with the administration of intravenous glucose.
3. Carbohydrates in the blood.
Glucose is the main marker of carbohydrate metabolism occurring in the body. If a biochemical analysis shows an increase in the indicator, this indicates that the person has diabetes or a condition preceding it. However, in some cases, such results can occur due to burns, injuries, consumption of large amounts of sugar, and poor preparation for the test. Sometimes an increased amount of glucose in the blood is observed in diseases associated with the liver or pancreas.
To identify disorders of carbohydrate metabolism, in addition to assessing blood glucose, doctors may prescribe a determination of the amount of glycated or glycolyzed proteins (glycolyzed hemoglobin, glycated albumin (fructosamine), glycated lipoprotein).
If glucose levels in a biochemical blood test are below normal, this indicates hypoglycemia, if higher, this indicates hyperglycemia.
Possible causes of hypoglycemia | Possible causes of hyperglycemia |
Poor nutrition, fasting and dieting | Diabetes mellitus type 1 and 2 |
Diseases associated with the gastrointestinal tract that cause poor absorption of carbohydrates (colitis, enteritis, etc.) | Injuries, brain tumors (often pituitary gland) |
Hypothyroidism | Tumor neoplasms, diseases of the adrenal cortex |
Liver diseases | Thyrotoxicosis, diseases associated with the thyroid gland |
Long-term uncontrolled use of drugs containing insulin, as well as hypoglycemic medications | Epileptic syndrome |
Encephalitis, meningitis, meningoencephalitis | Increased excitability, psycho-emotional instability |
Insufficiency of adrenal cortex function | Long-term treatment with glucocorticosteroids |
4. Pigments in biochemical blood analysis.
As a result of combining with iron, chromium or copper, some types of proteins acquire a specific color. As they break down, bilirubin is released into the blood, which can be in free or indirect form. Further, during certain processes, it is transformed into a bound state.
In a biochemical blood test, three hemoglobinogenic pigments are identified, namely total, direct (conjugated, bound) and indirect (unbound, free, unconjugated) bilirubin. All of them can indicate the presence of diseases or pathologies in the body. In this case, special attention is paid to free bilirubin, since it is toxic.
An increase in pigment in the blood can occur as a result of genetic diseases, organ or tissue transplantation, or blood transfusions. The basis of diagnosis is the ratio of bilirubin fractions. For example, if elevated levels are observed, this may indicate diseases of the biliary tract or liver.
5. Bilirubin.
After bilirubin passes through the gallbladder and liver, it ends up in the intestines. Here it is converted into urobilinogen compound, that is, a pigment that colors feces and urine.
If the gallbladder, liver or bile ducts are not working well, then some of the bilirubin may remain in the human body. As it spreads through the tissues, they will turn yellow. The well-known name “jaundice” arose precisely because of this symptom. However, many are mistaken when they associate this disease only with hepatitis A. At the moment, jaundice can appear for three reasons:
- Due to poisoning of the body, including toxic, hemolytic anemia and pathologies of the spleen with concomitant hyperfunction. When the pigment protein breaks down too quickly, unbound bilirubin is produced in such quantities that the liver cannot process it. As a result, it begins to accumulate in tissues and blood.
- Due to liver failure caused by injury, hepatitis, tumors and cirrhosis, when the organ cannot process the required amount of bilirubin.
- This can be observed in diseases such as cholelithiasis, cholecystitis, acute cholangitis and tumors. All of them lead to the fact that the outflow of bile from the gallbladder is hampered due to compression of the pathways, and bilirubin flows back into the blood, and then into the tissues.
Total bilirubin is one of the main indicators of a biochemical blood test. As a rule, to diagnose diseases such as liver cirrhosis, jaundice, hepatitis of various etiologies, when characteristic symptoms appear, a specialist examines the level of fractions, that is, bilirubin (unbound and conjugated).
6. Lipids.
No less important indicators in a biochemical blood test are those that indicate the content of fats (lipids). They, in turn, make up the lipid spectrum. During the study, the specialist evaluates the level of lipoproteins (high, low density), which are commonly called “bad” or “good” cholesterol, total cholesterol and triglycerides. Based on the data obtained and the ratio of components, the atherogenicity coefficient is determined. If there is a need to clarify the diagnosis, an additional study is carried out to determine the amount of phospholipids.
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7. Cholesterol levels.
In an adult who has no health problems, the level of total cholesterol in a biochemical blood test should be in the range of 3.0–5.2 mmol/l, with 40–60% of it being considered “good.”
Cholesterol in the body can be contained in the form of a high molecular weight compound with proteins and low molecular weight. High-density lipoproteins, produced largely in the liver, are involved in the regulation of processes associated with hormones, the psycho-emotional state, as well as in the formation of the cell membrane, etc.
If we talk about low and very low density lipoproteins, they enter the human body most often with food. Over time, these compounds begin to accumulate in blood vessels and turn into cholesterol plaques. This in turn leads to the fact that the lumen of the vessel becomes narrower, and the blood supply to organs and tissues decreases. However, even in the case of destruction of lipoprotein accumulations, there is a danger that their fragments can lead to the formation of blood clots.
Increased total cholesterol | Lowering total cholesterol |
Poor nutrition, diabetes, obesity, myocardial infarction, hypertension, alcoholism, ischemia, gestation period, cholelithiasis, etc. | Liver pathologies, malnutrition, hyperthyroidism, gastrointestinal diseases in which lipid absorption is difficult, chronic obstructive pulmonary disease, rheumatoid arthritis |
8. Enzymes.
When it comes to enzymes in a biochemical blood test, these are most often “liver tests”, amylases, ALT and AST. If an extended study is carried out, then this list increases significantly.
9. Analysis for “liver tests”.
ALT levels, that is, alaminoninottransferase, provide information regarding how efficiently the liver works in the body. In some cases, they talk about problems with the heart muscle or skeletal muscles.
A blood test for the level of AST (aspartatominotransferase) is performed if there is a suspicion of diseases and pathologies of the liver, heart (rheumatic carditis, myocardial infarction, angina), as well as infectious inflammatory processes.
10. Alpha amylase and pancreatic amylase.
Without the presence of these enzymes in the blood, the breakdown of complex carbohydrates would be impossible. For diagnostic purposes, a biochemical blood test examines the concentration of amylase, and the indicators can be either below normal or above it.
As a rule, an increase indicates the presence of diseases associated with the pancreas. In some cases, a high concentration of amylase may indicate viral hepatitis, mumps (endemic mumps), alcoholism, and renal failure. In addition, an excess of amylase in the blood is observed with long-term use of glucocorticosteroids and tetracycline drugs.
Based on a drop in values below normal in a biochemical blood test, the following diseases and conditions can be diagnosed:
- thyrotoxicosis;
- gestational toxicosis accompanying the first trimester of pregnancy;
- necrosis of pancreatic tissue;
- myocardial infarction.
11. Creatine kinase and its fractions.
Based on the concentration of the creatine kinase enzyme in the blood, the specialist assesses how efficiently energy metabolism occurs in the tissues of the heart (CF), muscles (MM fraction), and brain (BB). Indicators above normal indicate that there is accelerated tissue breakdown. In order to diagnose myocardial infarction, understand how much tissue is affected, and also make a prognosis, the CF subtype of creatine kinase is used.
12. Lipase.
Lipase is responsible for the breakdown of neutral fats in the human body. Also, to obtain a more accurate diagnosis and information regarding how affected the organ is, the pancreatic lipase indicator is used, which is more valuable in terms of information content than amylase.
Level of nitrogen metabolism
Not only cell construction occurs in the body. They also break down, and in the process, nitrogenous bases accumulate. They are formed in the human liver and are excreted through the kidneys. Therefore, if nitrogen metabolism are elevated, then there is likely to be dysfunction of the liver or kidneys, as well as excessive breakdown of proteins. The main indicators of nitrogen metabolism are creatinine , urea . Ammonia, creatine, residual nitrogen, and uric acid are determined less frequently.
Urea (urea)
Reasons for the increase:
- glomerulonephritis, acute and chronic;
- nephrosclerosis;
- pyelonephritis;
- poisoning with various substances - dichloroethane, ethylene glycol, mercury salts;
- arterial hypertension;
- crash syndrome;
- polycystic kidney disease or tuberculosis ;
- renal failure.
Reasons causing the decrease:
- increased urine output;
- administration of glucose;
- liver failure;
- hemodialysis;
- decrease in metabolic processes;
- starvation;
- hypothyroidism
Creatinine
Reasons for the increase:
- renal failure in acute and chronic forms;
- decompensated diabetes mellitus ;
- hyperthyroidism;
- acromegaly;
- intestinal obstruction;
- muscle dystrophy;
- burns.
Uric acid
Reasons for the increase:
- leukemia;
- gout;
- vitamin B-12 deficiency;
- acute infectious diseases;
- Vaquez disease;
- liver diseases;
- severe diabetes mellitus;
- skin pathologies;
- carbon monoxide poisoning , barbiturates.