Complete blood count - basic blood indicators, their interpretation, meaning and norms in children and adults

Red blood cell histograms

The erythrocytometric curves recorded using the analyzers do not correspond to the Price-Jones curves, which can be obtained through numerous and lengthy measurements of the diameter of erythrocytes under a microscope (using an ocular micrometer, the diameter of no more than 300 erythrocytes is measured in a blood smear in 4-6 hours of working time). The fact is that the diameter of erythrocytes when the smear dries decreases by 10-15%; in thick smears the diameter of erythrocytes is smaller than in thin smears and, finally, in the direction of the smear the diameter of erythrocytes is greater than across. The conductometric method reflects the volume of cells, so it is impossible to compare the distribution curves of erythrocytes by volume and diameter. The histogram of the distribution of red blood cells by volume has a number of features when compared with that by diameter:

1. The volume distribution curve is much wider; the coefficient of variation when determining volume is 3 times higher than when determining diameter.

2. The distribution curve of erythrocyte diameters is symmetrical (Gaussian curve), and the distribution of cells by volume has a shift to the right, proportional to the coefficient of variation of diameters.

3. If the diameter distribution curve is multimodal (has several peaks), then the histogram of the distribution of red blood cells by volume can be

Indications for testing

MSI in a blood test is a highly informative indicator, thanks to which it is possible to assess the current state of the body, confirm the diagnosis, conduct differential diagnostics and study the dynamics of prescribed therapy. Typically, this test is prescribed at the MedArt clinic for:

• Preventive and clinical observation, including for pregnant women.
• Baseline examination during patient hospitalization.
• Suspicion of anemia (of any type).
• Diseases of the hematopoietic system.
• Infectious and inflammatory processes.
• Evaluation of the effectiveness of the started treatment.

It is important to understand that the MCH is not an independent indicator. To evaluate it, a detailed blood test is prescribed, reflecting the most complete picture of the bloodstream at the moment.

How to prepare for the test

To obtain the most reliable data, it is recommended to carry out a number of preparatory activities. They will help not to “blur” the overall picture and accurately diagnose any deviation from the norm. Before taking blood, you must refrain from eating at least 4 hours before the procedure. It is also recommended to exclude heavy physical activity, emotional disorders and stress the day before. When taking any medications, you should talk in advance with your doctor, who can evaluate their composition and understand whether taking them can affect the analysis. If medications affect the results, you will need to limit their use a few days before the test. You also need to stop drinking alcoholic beverages and drugs. To achieve reliability, it is better not to smoke before analysis.

The best option is to visit the laboratory in the morning, on an empty stomach. In the morning you are allowed to drink only a glass of clean water. Strong tea, coffee and any other snack are not allowed. If it is necessary to donate blood several times to monitor therapy or more detailed diagnostics, then it is best to do this at the same time and in a similar condition. It is also worth contacting an identical clinic or laboratory. By adhering to these rules, the influence of third-party factors on the results obtained will be reduced to almost zero.

MCH norm indicators

The average amount of hemoglobin in one red blood cell varies depending on age and gender. Its average value in a healthy adult is from 27 to 31 picograms (pg). The highest rates are observed in infants under 14 days of age. They can vary from 30 to 37 pg and, as they grow older, gradually decrease and are compared with the norm for adults. Norms for women

The norms for men are approximately the same as for women. Minimal deviations are observed. 46-6027-34 After 6027-35

Norms for children. It should be noted that these indicators are unstable; they can change within a matter of hours or days.

MCHC (Mean Corpuscular Hemoglobin Concentration) - the average concentration of hemoglobin in a red blood cell

Parameter calculation

MCHC reflects the concentration of hemoglobin in the “average” erythrocyte (the ratio of hemoglobin content to cell volume) and characterizes the degree of saturation of the erythrocyte with hemoglobin as a percentage. This parameter can be calculated using hemoglobin and hematocrit indicators:

MCHC = Hb (g/dL) 100/Ht (%).

Genetically determined indicator

The average hemoglobin content in an erythrocyte is the most stable, genetically determined indicator and for adults does not depend on age, gender, or race. The coefficient of variation of this parameter in patients in the clinic is 4–5%.

Of all the erythrocyte indices, MSHC is the least susceptible to fluctuations under pathological conditions. Therefore, its reduction is of great value in diagnosis:

• iron deficiency anemia,
• thalassemia,
• lead intoxication,
• some hemoglobinopathies.

Error indicator

For the same reason, the parameter can be used as an indicator of instrument error or inaccuracy made when preparing a sample for research. The stability of calibrations, the correct functioning of equipment - all this is useful to monitor using the current average MCHC value. It should fluctuate within 34±2 units.

Clinical and diagnostic value

How the research is carried out

To obtain data on MSI in a blood test, blood is drawn from a vein. In rare cases, it is possible to use finger capillaries (nowadays they are practically not used, as they are less accurate and informative). This procedure is performed by a nurse or laboratory worker who has the appropriate education and license to carry out this activity. Its duration is no more than 5 minutes and is accompanied by slight pain and discomfort at the puncture site. However, the discomfort quickly disappears, and a small bruise may remain at the puncture site. Persons who are afraid of the sight of blood are strongly advised to turn away and not look at the hand until the end of the procedure. But to prevent loss of consciousness and quickly restore consciousness, a cotton pad and ammonia are always present in the office. Blood sampling is carried out in several successive stages:

• Applying a rubber or fabric tourniquet with clamps to the forearm of the patient, who must work his fists a little (clench and unclench his hand several times to better fill the vessels).
• The technician or nurse selects the most appropriate vein and cleans the skin with an alcohol swab.
• Inserting a needle into a vein, through which blood flows into a syringe or special tube. Often, no more than 5 ml is collected.
• Remove the needle and apply cotton wool soaked in alcohol to the puncture site.

To prevent bruising or bruising, the patient is asked to press his forearm to his shoulder for a few minutes. At this point, the procedure ends and the medical worker signs the tube, after which the resulting material is placed in the analyzer. Its use makes it possible to automatically count all types of blood cells, including red blood cells. The obtained data is sent to the attending physician, after which the MCH blood test begins to be deciphered.

Deciphering the MCH blood test

Increase in MCH

If the MCH exceeds the upper permissible limit, then this indicates the presence of a pathological process in the body. Diagnosis of the underlying disease that provoked this change is carried out after determining the cause. In most cases, a similar jump is observed with hyperchromia. This term refers to a condition characterized by an increase in hemoglobin in red blood cells. As a rule, it develops when a person has some type of anemia. The MCH level in the blood increases under the following conditions:

• Severe leukocytosis.
• Exceeding the norm for the amount of fat.
• Increase in the number of heparins.
• Destruction of red blood cells caused by a number of diseases (malaria, poisoning with certain poisons or chemicals, hemolytic anemia, systemic lupus erythematosus, kidney damage, toxoplasmosis, systemic scleroderma, viral hepatitis B and C).

The reasons for such deviations may be a deficiency of vitamin B12, B9 and the use of certain medications (therefore, it is extremely important to carefully study the side effects indicated in the attached instructions, and also stop using the drug before taking the test). To prevent receiving false information, it is recommended to first consult with a doctor and clarify which medications the patient is currently taking. For example, in women, MSI may be affected by a long and uninterrupted course of contraceptive medications.

Other etiological factors that can cause an increase in MSI are:

• Liver damage (especially hepatitis and cirrhosis)
• Excessive drinking of alcoholic beverages and terminal stages of alcoholism.
• Leukemia.
• Neoplasms (both malignant and benign), localized in the bloodstream and other internal organs.

In addition, high hemoglobin levels are observed in individuals suffering from hyperthyroidism. This is a disease of the endocrine system, characterized by damage to the thyroid gland. Its main symptoms are organ enlargement, exophthalmos, increased physical activity, emotional lability, excessive appetite, weight loss, abnormal activity and accelerated metabolism. Often this pathology is diagnosed in residents of an endemic zone, in which, due to natural conditions, there is a low concentration of iodine.

Decreased MCH

If the interpretation of the MCH blood test showed a decrease in this indicator, then this result indicates the presence of another form of anemia - anemia of the hypochromic type. The most common type of this pathology is iron deficiency anemia, characterized by insufficient absorption of iron.

With a decrease in the relationship between Fe and hemoglobin, a noticeable change in the normal parameters of a clinical blood test occurs. In most cases, this indicates the following diseases:

• A source of inflammation localized in any part of the body.
• Disorder of metabolic processes affecting iron metabolism.
• Hypovitaminosis caused by malnutrition, internal pathologies and other etiologies.
• An intoxication period that arose against the background of long-term lead poisoning.

A decrease in MCH has a strong impact on the normal course of biochemical processes, as a result of which a person’s condition significantly worsens. As a rule, this causes rapid fatigue, weakness, pale skin, dry skin, brittle hair and nails. Often there is a feeling of dumbness in the upper and lower extremities, ulcers in the corners of the mouth and irregular heart rhythm.

Having identified any irregularities in the MCH indicators, you must immediately contact a qualified doctor. Only he, based on the laboratory data obtained, will be able to make an accurate diagnosis and select the most effective treatment method.