Biochemical blood test A biochemical general therapeutic blood test is one of the most common tests used to assess health status. Cost of analysis
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A complete blood count is one of the most common and most necessary diagnostic tests[1]. It allows the doctor to assess the patient’s blood parameters and quickly draw initial conclusions about the state of his health.
The value of normal hematocrit in humans
The body of a healthy adult contains approximately 4.5-5 liters of blood. It contains formed elements and cells - red blood cells, platelets, leukocytes, as well as a liquid part called plasma.
Some blood components, for example, red blood cells, do not have all the necessary components of a human cell, losing them during the maturation process. Therefore, red blood cells and platelets are called blood cells, not cells.
In different categories of patients, the normal values of various parameters of the blood tested will differ. So, for most men, the hematocrit will be higher: 40-41%, and in some cases it can reach up to 51%, which is due to its slower renewal.
In healthy women, the hematocrit usually ranges from 36 to 42%. This is due to physiological features - due to regular menstrual bleeding, blood is renewed more often to replenish its volume. During pregnancy, from the 20th week, the indicator begins to decrease, which is also not considered a deviation.
In children, hematocrit differs at different age periods:
- 44-62% for newborns;
- 32-43% for babies up to three months;
- 36-43% for children under one year of age;
- 35-47% (up to 52% for boys) - in the first ten years.
In subsequent years, the hematocrit norm depends on gender and practically corresponds to the values of an adult.
Symptoms of high and low WBC
WBC in a blood test is a number that can be used to fairly accurately assess the functioning of the immune system and overall health. A high value, above the upper limit of normal, is called leukocytosis. This is a signal about inflammatory processes occurring in the body or a decrease in general immunity.
Leukocytosis is not necessarily associated with disease. An increase in the indicator may also depend on heavy physical activity or stress. A small jump also occurs after eating and in women during pregnancy.
Symptoms of leukocytosis:
- causeless fatigue, lethargy;
- temperature increase;
- bruises or hematomas even with minor bruises, and sometimes for no reason;
- pain in the limbs or abdomen;
- decreased appetite and weight loss;
- labored breathing.
A low level of white blood cells is called leukopenia. The danger of this condition is that it does not have pronounced symptoms. Signs of the disease in the initial stage are easily confused with ordinary fatigue.
At a later stage, the following are observed:
- high temperature, chills;
- accelerated pulse;
- causeless anxiety;
- headache;
- exhaustion of the body;
- pneumonia, blood infection.
Swelling of the glands, enlargement of the spleen or tonsils is also possible. If leukopenia develops as a result of taking medications, then the onset of symptoms is explosive.
Methods for determining hematocrit
The indicator is determined as a percentage by calculating the amount of formed elements in whole blood. It is calculated using special instruments or manually.
Centrifugation using the Wintrobe method
The blood is exposed to centrifugal force for 10-30 minutes. The formed elements are heavier than plasma, so they settle to the bottom of the test tube. The hematocrit is determined by the ratio of sediment to the total volume of biomaterial.
Calculation of the indicator using the formula
The ratio of the number of red blood cells to the total blood volume can be calculated mathematically. To do this, the following indicators are required:
- total hemoglobin concentration (ctHB);
- red blood cell count (RBC);
- mean erythrocyte volume (MCV);
- mean erythrocyte hemoglobin concentration (MCHC).
The hematocrit number (HCT) is determined by one of the formulas:
- HCT (%)=(ctHB (mmol/l)*0.0485+0.0083)*100
- HCT (%)=0.1*MCV*RBC
- HCT (%)=ctHB/MCHC*100
Direct blood cell counting method
In a given volume of biomaterial, visible blood elements are counted manually or using hematological analyzers. The method is highly accurate, and the measurement process does not take much time - no more than five minutes, but the equipment required is very expensive.
Manual counting method
Blood collected using an anticoagulant is placed in a dry, clean tube and allowed to settle. In this case, the formed elements that have greater weight settle to the bottom of the container, and the light plasma rises to the top, forming two fractions of red and yellow colors, respectively. The hematocrit indicator can be determined by the divisions on the test tube. This method is the least accurate, its error is up to 20%, so it is currently not used in laboratories.
When is a hematocrit test performed?
Most often, hematocrit is determined as part of a general (clinical) blood test. Therefore, at present this parameter of a clinical blood test is not prescribed separately. The hematocrit level changes when:
- disorder of the blood coagulation system;
- dehydration;
- anemia or polycythemia;
- bleeding.
Assessing the hematocrit level is important when determining indications for the need for blood transfusion or the effectiveness of blood transfusion, during hemodialysis, and some operations. To determine the hematocrit number, venous or capillary blood is taken.
Indications for WBC testing
WBC in a blood test is a value that is used to evaluate existing or potential health threats.
A blood test for leukocytes is prescribed in the following cases:
- suspected infection or inflammatory process;
- a prolonged increase in body temperature that does not subside;
- constant headaches, frequent discomfort in joints or bones;
- suspicion of impaired hematopoietic function;
- to monitor the treatment.
The appointment for the analysis is given by the attending physician. The first specialist to whom the patient turns should be a therapist. If necessary, this doctor prescribes laboratory tests or gives referrals to specialists. If the patient has a chronic disease, then you can immediately contact a specialized specialist.
Increased hematocrit
An increase in hematocrit occurs with an increase in the number of blood cells - polycythemia - and a lack of fluid in the body. An increase in the indicator may indicate serious diseases accompanied by blood thickening and thrombotic complications.
Causes
Hematocrit increases due to stress, taking corticosteroid drugs and diuretics, traumatic shock accompanied by intense pain, as well as when climbing to high altitudes, smoking, or playing sports using anabolic steroids to gain muscle mass.
An increase in the indicator may indicate the following diseases:
- dehydration due to vomiting, profuse diarrhea, overheating or heat stroke, excessive sweating, insufficient fluids;
- heavy bleeding in the midst or immediately after it stops;
- pathologies accompanied by a decrease in blood plasma volume, for example, peritonitis, thrombosis, diabetes, burn disease;
- renal dysfunction - hydronephrosis, oncology, polycystic disease;
- vitamin B12 or iron deficiency anemia;
- leukemia;
- erythrocytosis;
- defects and coronary heart disease, heart failure;
- intestinal obstruction;
- bronchial asthma, pulmonary emphysema, obstructive bronchitis.
Symptoms
An increase in blood viscosity leads to thrombus formation. The latter can manifest itself in the form of tingling or various pains and numbness in the limbs. If the cause of increased blood viscosity is not determined in time, serious complications such as myocardial infarction, stroke, gangrene and even death may develop.
Treatment
Treatment is carried out not for the changed hematocrit level itself, but for the conditions or diseases that caused these changes. In some situations, when serious causes for a slightly changed hematocrit level have been excluded, no treatment is required. But usually such situations are short-lived, in the case of physiological reasons for changes in hematocrit levels.
Causes of low WBC level in blood test
A decrease in the number of leukocytes in the blood below normal physiological values is called leukopenia. This condition usually indicates a decreased immune response. The reasons for its occurrence:
- immunosuppressive therapy;
- leukemia;
- hypoplastic anemia;
- viral infections (viral hepatitis, rubella, measles, influenza);
- systemic lupus erythematosus and other long-term systemic diseases;
- radiation sickness;
- chronic intoxication.
WBC in the blood can be lowered against the background of long-term depressive states and fasting.
Decreased hematocrit
A decreased hematocrit occurs when the number of red blood cells or their size decreases - erythrocytopenia. The cause may also be the accumulation of water in the body when the blood becomes thinner - hyperhydration, as well as hyperproteinemia or the accumulation of proteins in the plasma, which contributes to fluid retention.
Causes
A decrease in hematocrit is facilitated by prolonged immobility, fasting or a strict diet, taking anticoagulants and antiplatelet agents, and intravenous infusions in large volumes; heavy drinking, chronic alcoholism, excessive salt intake, menstruation in women.
Also, a downward change in the indicator may indicate the following pathologies:
- iron-, B12- or folate-deficiency anemia;
- severe bleeding;
- impaired hemoglobin production in sickle cell anemia;
- fibrous degeneration of the liver - cirrhosis;
- disruption of the urinary system;
- hemolysis of erythrocytes - destruction of red blood cells due to hereditary mutation, autoimmune processes or toxic effects on blood cells;
- malaria, typhoid fever;
- oncological diseases of the bone marrow or its metastatic lesions from other organs;
- an increase in the amount of protein in plasma due to vomiting, diarrhea, blood cancer and other conditions.
During pregnancy, a decrease in hematocrit can be observed in the case of toxicosis, a very young age of the mother, multiple pregnancies, a short period of time between pregnancies, and also after the 20th week of gestation due to a physiological increase in fluid in the body.
Symptoms
A decrease in hematocrit in the blood is accompanied by hypoxia of various organs, since it is the red blood cells that normally carry oxygen throughout the body. This condition is manifested by the following symptoms:
- fast fatiguability;
- general weakness;
- drowsiness;
- increased heart rate and breathing;
- feeling of lack of air;
- headache, dizziness;
- decreased memory and concentration;
- hair loss;
- marbling or pallor of the skin.
Treatment
A decrease in hematocrit in an adult to 35-30% requires outpatient medical supervision, exclusion of possible serious diseases, and dietary adjustments with increased consumption of animal products, in particular, red meat and liver, and leafy greens. An indicator below 13% is typical for life-threatening pathologies and is usually detected in patients in serious condition in the hospital. Patient management tactics are determined by the underlying disease that led to a change in hematocrit level.
Author:
Baktyshev Alexey Ilyich, General Practitioner (family doctor), Ultrasound Doctor, Chief Physician
How and under what conditions are leukocytes produced?
Blood cells that recognize and eliminate foreign elements are called leukocytes. These are special elements of the immune system that are responsible for protecting against pathogenic bacteria and viruses, foreign bodies, any objects that can cause harm, and cleanse it of dead or damaged own cells.
The term “leukocytes” is formed from a combination of two words from the ancient Greek language: “leukos” (white) and “cytos” (receptacle, body).
There are several types of such cells:
- Neutrophils make up 55% of the total. Protection against bacterial and fungal infections depends on them.
- Basophils (0.5%) are scout cells; they find even single foreign elements. Their job is to increase blood flow, mobilize other cells to the site of inflammation, and fight allergens.
- Eosinophils (2.5%) are part of the innate immune system that protects against allergens, parasites, and helminths.
- Monocytes (5%) are responsible for the absorption of dangerous particles and dead cells.
- Lymphocytes (35%) support general immunity, store hereditary information, and regulate the functioning of other types of immune system elements.
White blood cells are produced by red (blood-forming) bone marrow. This organ is located in the internal cavities of the pelvic bones, sternum, and in the end sections of the tubular bones. It is also found inside the vertebrae, but in smaller quantities.
Hematopoietic bone marrow is the only source of cells called stem cells. Their main advantage is that they are close in structure to embryonic ones. The lifespan of leukocyte cells ranges from several hours to several years, depending on the type of leukocyte.
Some leukocytes capture and digest any foreign microorganisms and dead own cells, some produce antibodies that destroy all kinds of pathogens (disease-causing microorganisms) or accelerate blood flow to the necessary places. White blood cells are capable of accumulating hereditary memory, that is, “children” retain information about the threats that their “parents” had to face.
