Laboratory tests are an important part of the diagnosis of hematological diseases.
I. General blood tests
Changes in the quality and quantity of peripheral blood cells can often reflect the hematopoietic changes in bone marrow. High-quality routine blood tests can not only provide clinicians with clues for further examination, but sometimes even provide an important basis for the diagnosis of certain hematological diseases. Therefore, the general examination of peripheral blood is regarded as an indispensable laboratory tool for the diagnosis of hematological diseases.
In recent years, hematology analyzers have largely replaced the traditional manual microscopic counting method for routine blood testing, and these instruments can simultaneously measure total red blood cell count, hemoglobin content, hematocrit, red blood cell distribution width, average red blood cell volume, average hemoglobin content, average hemoglobin concentration, total platelet count, platelet distribution width, average platelet volume, total white blood cell count, white blood cell classification Some instruments can also measure reticulocyte count.
Although the above instruments can provide a number of indicators, the analysis of morphological and pathological changes in leukocytes, erythrocytes and platelets still needs to be established by smear staining microscopy.
1.Changes in the number of red blood cells and hemoglobin.
2, morphological changes of red blood cells.
3.Changes in the number and morphology of white blood cells.
4.Changes in the number and morphology of platelets.
5.Reductions in whole blood cells.
Bone marrow examination
(A) Bone marrow smear examination
1.Bone marrow proliferation degree.
2. Granulocyte/red ratio.
3.Increased number of primitive cells.
4.Chemical staining of blood cells.
(B) Bone marrow biopsy
Bone marrow biopsy is used to take sections of bone marrow tissue for pathological histological examination to understand the density of bone marrow hematopoietic cells, changes in bone marrow hematopoietic interstitium, and structural changes in bone tissue, which makes up for some deficiencies of bone marrow smear examination. It is more helpful for the diagnosis of aplastic anemia, myelodysplastic syndrome, myelofibrosis, myelosclerosis, and bone marrow metastasis of malignant tumors. Bone marrow biopsy and bone marrow cytology cooperate and complement each other, and thus have important clinical application value.
(iii) Bone marrow cell electron microscopy
With the continuous progress of research methods, electron microscopy combined with cytochemistry and immunology has gradually improved people’s understanding of cell structure, and the observation of ultrastructure of bone marrow cells by transmission electron microscopy and scanning electron microscopy has added a new basis for the diagnosis of hematological diseases. For example, the surface of hair cells in polychromatic leukemia is uneven, and many villi-like and finger-like protrusions can be seen, and ribosomal lamellar complexes can be seen in the cytoplasm; parallel tube structures can be seen in the cytoplasm of large granular lymphocytic leukemia cells; in addition, electron microscopic myeloperoxidase staining for acute undifferentiated leukemia and platelet peroxidase for acute megakaryocytic leukemia are of diagnostic value.
Blood biochemical examination
Biochemical tests involve structural and metabolic changes of substances related to the function of various types of blood cells. In order to correctly select the examination items and interpret the results, it is necessary to have an understanding of the relationship between the structure, metabolism and function of various types of blood cells, which will be introduced in the relevant chapters, and the following are the commonly used biochemical tests.
1.Biochemical tests related to red blood cells.
2.Biochemical examination of leukocytes.
3. Laboratory tests related to coagulopathies.
In leukemia and lymphoma, uric acid and lactate dehydrogenase activity are often elevated in the serum when cells are degraded in large quantities.
IV. Histopathological examination
In the diagnosis of hematological diseases, histopathological examination is an important diagnostic technique. In addition to bone marrow biopsy, there are lymph node biopsy, spleen biopsy, and cytological pathological examination of body fluids. Lymph node biopsy is mainly used for the diagnosis of diseases with enlarged lymph nodes, such as lymphoma, and its differentiation from lymphadenitis and metastatic cancer; spleen biopsy is mainly used for the diagnosis of diseases with significant enlargement of the spleen. Cytological examination of body fluids includes the examination of tumor cells (or leukemia cells) in pleural fluid, ascites and cerebrospinal fluid, which are valuable for diagnosis, treatment and prognosis.
V. Immunological examination
Immunological examination of hematological diseases has developed rapidly, mainly thanks to the progress of hybridoma technology, and a large number of specific monoclonal antibodies have appeared; the application of radioimmunoassay technology makes the combination of high specificity of antigen-antibody reaction and high sensitivity of radionuclide measurement, which can determine trace substances in blood; the application of flow cytometry makes the analysis with the advantages of rapid, accurate and quantitative, and combined with immunofluorescence technology, it is possible to determine not only the antigens containing a certain antigen, but also the immune cells. In combination with immunofluorescence, it is possible to determine not only the number of cells containing a certain antigen, but also the amount of antigen contained on each cell, and to “extract” the desired cell from a large number of cells specifically for research. The immunological tests commonly used in the diagnosis of hematological diseases are described below.
(A) Immunophenotyping of leukemia
1.T lymphocyte markers.
2.B lymphocyte markers.
3.Granulocyte and monocyte markers.
4.platelet and megakaryocyte markers.
5.Activated cell markers.
6.Non-spectrum cell markers.
Immunophenotyping of leukemia provides assistance in the diagnosis of the disease and helps to understand the relationship between immunophenotyping and clinical course, disease prognosis and treatment response, helps to select chemotherapeutic drugs correctly, and creates conditions for the removal of residual leukemic cells during autologous bone marrow transplantation and the development of guide drugs.
(B) Anti-hematocrit antibody test
1.Anti-erythrocyte antibodies.
2.Anti-leukocyte antibodies.
3.anti-platelet antibodies.
(C) immunoglobulin content and immunoelectrophoresis
(D) the determination of hematopoietic cell regulatory factors and their receptors
Cytogenetic and molecular biology examination
1.Chromosome examination: The application of cytogenetics in hematological oncology started in 1960. Following the discovery of Ph chromosome, chromosome abnormalities in hematological malignancies have been extensively studied. Chromosomal abnormalities in hematological diseases include both quantitative and structural abnormalities. Quantitative abnormalities are classified as haploid abnormalities and aneuploid abnormalities; structural abnormalities include breaks, deletions, duplications, translocations and inversions. The common chromosomal changes of hematological diseases are shown in Table 1-2.
Gene diagnosis: The progress of molecular biology has made it possible to conduct gene diagnosis for many diseases. Gene diagnosis directly targets the disease-causing genes, which not only can diagnose diseases more accurately, but also can deeply explore the relationship between the type of gene variation and the clinical process and prognosis, which is more important for the gene therapy that has emerged.
VII. Hematopoietic cell culture and testing technology
Hematopoietic stem cells and progenitor cells do not have specific morphological characteristics, and thus they cannot be identified by general methods. In vitro, if there is a suitable conditioned culture medium, specific stimulating factors, temperature and humidity, hematopoietic progenitor cells can survive and proliferate and differentiate into a sub-colony, and the number and morphology of the formed colonies can reflect the number and proliferation and differentiation potential of the progenitor cells. Each progenitor cell is called a colony-forming unit.
The clinical applications of hematopoietic cell culture technology can be summarized as follows.
1. To assist in the diagnosis of various hematological diseases, for example, in aplastic anemia the CFU-GM, CFU-E and BFU-E in bone marrow and peripheral blood are significantly reduced in most patients; while in chronic granulocytic leukemia they can be about 10 to 50 times higher than normal; in acute leukemia, except for granulocytic and erythroid colonies, which are significantly reduced, most of them can only form clusters. For example, in aplastic anemia, different combinations of cells and serum components can be cultured to classify the disease into different types such as hematopoietic stem cell deficiency, abnormalities of humoral regulatory factors and microenvironmental defects.
2.To determine whether there are active substances in the serum that stimulate or inhibit hematopoiesis, or to determine whether there are inhibitory cell components, normal bone marrow cells can be cultured after adding the serum to be tested or a purified component, or the cells to be tested can be mixed with normal cells and cultured to observe the changes in colony formation.
3. To study the effect of drugs on hematopoietic cells, add a certain amount of the drug to be tested in the culture system and observe the effect of the drug on hematopoietic progenitor cells.
VIII. Radionuclide examination
The application of radionuclides to the relevant blood cells and other blood components for kinetic and pathophysiological studies, and for bone marrow, spleen scan imaging can show the production, distribution and destruction sites of blood cells and changes in pathological conditions, which can help the diagnosis of certain blood diseases and the exploration of pathogenesis.
1.Blood volume measurement.
2.Red blood cell life span measurement.
3.Iron metabolism test.
4.Spleen scan.
5.Bone marrow imaging.