Blood test used to refer to routine blood examination and manual counting under a microscope. It includes red blood cells, hemoglobin, white blood cells and their classification, platelet count and so on. * * * There are 65,438+00 projects. It takes 10 minutes to do a patient's blood routine examination.
With the rapid development of science and technology, medical laboratory instruments have been automated. At present, most hospitals use automated hematology analyzer for routine blood tests (currently called hematological analysis). Only 0. 1 ml anticoagulant (about two drops of blood) is needed for each examination, and more than 20 results can be detected and printed in 30 seconds or 1 minute. However, most of these results are reported in English abbreviations, and some of them are only introduced in laboratory medicine books, so it is difficult for patients to understand their significance.
Blood test is to detect and analyze the quantity and quality of visible components in blood, namely red blood cells, white blood cells and platelets. These three systems and plasma constitute blood, which constantly flows in the human circulatory system and participates in the metabolism and every functional activity of the body. Therefore, blood plays an important role in ensuring human metabolism, functional adjustment and internal and external environmental balance. The pathological changes of any tangible components in the blood will affect the tissues and organs of the whole body; On the contrary, pathological changes in tissues or organs will cause changes in blood components, so hematological analysis and its results are very helpful to understand the severity of diseases.
Automatic analyzer can detect and report eight parameters of red blood cell system and red blood cell histogram. The related project names and their reference values are as follows:
1. Red blood cell (RBC): male 4.0x10/2 ~ 5.5x10+02/L, female 3.5x10/2 ~ 5.ox65433.
2. Hemoglobin (HGB or Hb): male 120 ~ 160g/L, female10 ~150g/L;
3.HCT。 Hct (also called hematocrit, PCV): 0.42-0.49 L/L (42% ~ 49%) for males and 0.37-0.43 L/L (37% ~ 43%) for females;
4. Average hematocrit (MCV): 80-100L;
5. Average erythrocyte hemoglobin content (MCH): 27-33 picograms;
6. Mean hemoglobin content of red blood cells (MCHC): 320 ~ 360 g/L;
7. Average diameter of red blood cells (MCD): 6-9 microns (average 7.2 microns);
8. Red blood cell volume distribution width (RDW):11.5% ~14.5%.
Note: The above units are sometimes expressed by English symbols, such as L (liter), fL (soaring), G (gram), pg (pique) and um (micron).
With these reference values, we can check whether the test results are normal. If the result is different from the reference value, what's the point?
Red blood cells and hemoglobin: hemoglobin is the main component of red blood cells, and RBC and Hb can be separated under pathological conditions. Under normal circumstances, about1120 RBC decays and dies every day, and at the same time,1120 RBC is produced, which keeps the dynamic balance between the production and decay of RBC, so healthy adults donate 200 ~ 300ml blood every 3 ~ 4 months, which will not affect their health. Many reasons can destroy the dynamic balance of erythropoiesis and decline, leading to the decrease or increase of erythrocytes and hemoglobin, or the change of quality.
For example, persistent severe vomiting, severe diarrhea, extensive burns, excessive sweating, etc. It can make the water in plasma lose and the blood concentrate, thus increasing red blood cells and hemoglobin. Chronic adrenocortical hypofunction, diabetes insipidus, hyperthyroidism, etc. It will also cause a relative increase in RBC and Hb content.
The above introduces the significance of the increase of red blood cells and hemoglobin, while the decrease of red blood cells and hemoglobin is more common in clinic, and the condition is serious and complicated.
Generally speaking, the contents of red blood cells and hemoglobin in blood are the same, and the determination method of hemoglobin is direct and accurate, so hemoglobin is often used as a priority reference index. Adult male Hb less than 120g/L (female HB less than 1 10g/L) is anemia. Anemia is divided into four grades according to the degree of Hb reduction: mild, Hb is less than normal but greater than 90 g/L; Moderately, Hb is less than 90g/L but more than 60g/L; Severe, Hb is less than 60 g/L but more than 30 g/L; Extreme, Hb is less than 30 g/L.
Anemia is divided into physiological and pathological. From infants after 3 months to children before 15 years old, RBC and Hb are lower than those of normal adults10%-20% due to rapid growth and insufficient supply of hematopoietic materials; Pregnant women in the second and third trimester of pregnancy may have mild anemia due to insufficient hematopoietic substances and relatively increased blood volume; Due to the gradual weakening of hematopoietic function of bone marrow, the contents of red blood cells and hemoglobin in the elderly may decrease, which belongs to physiological anemia and generally does not cause serious harm in clinic, and can be improved through symptomatic treatment.
Pathological anemia has three main reasons:
Decreased erythropoiesis. Including bone marrow hematopoietic failure, such as aplastic anemia, bone marrow fibrosis and other anemia, or anemia caused by lack or utilization of hematopoietic substances, such as iron deficiency anemia, sideroblastic anemia, megaloblastic anemia caused by folic acid and vitamin B 12 deficiency.
Too much damage to red blood cells. Anemia caused by excessive destruction of red blood cells due to genetic defects of red blood cell membranes and enzymes or external factors, such as hereditary spherocytosis, marine anemia, paroxysmal nocturnal hemoglobinuria, abnormal hemoglobinopathy, immune hemolytic anemia and hemolytic anemia caused by some chemical and biological factors.
Excessive bleeding. Acute or chronic blood loss caused by various reasons, such as acute blood loss caused by trauma and operation, chronic blood loss caused by digestive tract ulcer and hookworm disease, can all lead to anemia in different degrees. There are also various chronic diseases or malignant diseases, such as chronic kidney disease and malignant tumors, which can also cause anemia. Although this anemia is accompanied by related diseases, it cannot be ignored. Some malignant diseases are diagnosed because of the symptoms of anemia.
The following tests in the red blood cell system have certain reference value:
Hematocrit (HCt, HCT, also known as hematocrit) refers to the ratio of red blood cells to plasma volume in a certain volume of blood. Various reasons, such as water loss and a large amount of plasma exudation, can concentrate blood and increase HCt; Anemia caused by various reasons will reduce HCT.
The mean volume of red blood cells (MCV) indicates the mean volume of each red blood cell. The MCV of normal people is 80 ~ 100 (1 skyrocketing = 10- 15 liters). When MCV rises below 80, red blood cells are small cells, and when MCV rises above 100, they are large cells. Both large cells and small cells indicate anemia, but the types of anemia are different.
In addition, the changes of red blood cell average hemoglobin content (MCH, that is, the amount of Hb contained in each red blood cell), red blood cell average hemoglobin concentration (MCHC, indicating the hemoglobin concentration in each liter of red blood cell), red blood cell average diameter (MCD), red blood cell volume distribution width (RDW) and red blood cell average thickness (MCT) can also reflect different types of anemia.