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MindMap Gallery Introduction to laboratory diagnostics, hematology tests
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Introduction to laboratory diagnostics, hematology tests
Laboratory diagnosis is a clinical diagnostic method based on laboratory test results or data, combined with other clinical data, and after comprehensive analysis, used in clinical diagnosis, differential diagnosis, condition observation, efficacy monitoring, and prognosis judgment.
Edited at 2023-12-26 09:47:51
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Introduction to laboratory diagnostics, hematology tests
- bacteria
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- Reproductive development of animals
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- Outline
Experimental diagnosis
Chapter 1 Introduction
1. The concept of experimental diagnosis
laboratory diagnosis
It is a clinical diagnostic method based on laboratory test results or data, combined with other clinical data, and after comprehensive analysis, used in clinical diagnosis, differential diagnosis, disease observation, efficacy monitoring and prognosis judgment.
status
It is an important bridge between basic medicine and clinical medicine.
Main content and application scope
Main contents of experimental diagnosis
clinical hematology tests
clinical biochemistry examination
clinical immunological examination
Clinical etiological examination
Body fluid and excrement examination
Other examinations: Chromosome examination for genetic diseases, genetic examination
Application scope of experimental diagnosis
(1) Serving clinical medical work
Disease diagnosis and differential diagnosis, observation of therapeutic effects and prognosis judgment
(2) Provide a basis for carrying out prevention work
(3) Conduct social census
(4) Carry out health consultation
2. Quality system and influencing factors of experimental diagnosis
Perfect quality assurance system
Purpose: To detect errors in the analysis process, control relevant aspects of the analysis, and ensure that the results are accurate and credible.
Classification
In-house quality control
Room quality control
Laboratory quality system
Factors affecting experimental diagnosis
1. Pre-laboratory factors
More than 60% of the reasons for errors in test results come from the laboratory, mainly the collection and processing of specimens.
2. Laboratory factors
Specimen quality and processing, instruments and reagents, personnel skills and knowledge, operating techniques and methods, quality control materials and standards, safety and cost, etc.
3. Post-laboratory factors
Inspection records, result writing, information input and transmission, laboratory and clinical communication, etc.
3. Collection and processing of patient specimens
patient specimen
Blood sample examination is the most important
blood, urine, feces
Various secretions
Various physiological and pathological body fluids
4. Clinical application and evaluation of experimental diagnosis
Correctly choose laboratory inspection items
in principle
Targeted
effectiveness
Economy
timeliness
Evaluation indicators for diagnostic tests
diagnostic sensitivity
diagnostic specificity
diagnostic accuracy
5. Experimental diagnosis reference range, medical decision level and critical value
Reference range
Various test items have judgment standards, the so-called reference values or reference ranges, which are used to measure whether the results of the tested specimens are abnormal.
Medical Decision Level (MDL)
By observing whether the measured value is higher or lower than these limits, it can play a role in excluding or confirming disease diagnosis, grading or classifying certain diseases, or making an estimate of prognosis.
critical value
Critical values refer to when certain test results are abnormal and exceed a certain threshold, which may endanger the patient's life and the doctor must deal with it urgently. This is called critical value.
Chapter 2 Hematology Tests
Section 1 General tests of blood
red blood cells
Red blood cell and hemoglobin testing
Hemoglobin and red blood cell count reference values
Increased red blood cells and hemoglobin
relative increase
Plasma volume decreases, resulting in a relative increase in red blood cell volume, which is seen in severe vomiting, diarrhea, heavy sweating, and large-area burns.
absolute increase
Secondary polycythemia—increased EPO
Compensatory increase in erythropoietin: the degree of increase is proportional to the degree of hypoxia, such as severe chronic cardiopulmonary disease.
Uncompensated increase in erythropoietin: related to certain tumors or renal diseases.
Polycythemia vera (a myeloproliferative tumor characterized by an increase in the number of red blood cells)
Decreased red blood cells and hemoglobin
Physiological reduction
Infants and children under 15 years old have rapid physical development and a sharp increase in blood volume, but there are insufficient hematopoietic raw materials.
Plasma volume increases in the second and third trimester of pregnancy, diluting the blood
Significant deterioration of hematopoietic function in the elderly
Pathological reduction
Decreased red blood cell production: iron deficiency anemia, megaloblastic anemia, aplastic anemia
Increased destruction of red blood cells: anemia
Excessive loss of red blood cells (blood loss): acute and chronic hemorrhagic anemia.
Red blood cell morphological changes
normal
Biconcave disc shape (deformed), uniform size, average diameter 7.2μm (6.7～7.7μm)
Wright's stain: light pink, well filled with hemoglobin, orthochromic, centripetal light staining, the size of the central light staining area is about 1/3 of the cell diameter
Seen in: healthy people, acute blood loss
Abnormal size (volume-diameter)
microerythrocytes
form
Diameter less than 6μm
occur
Occasionally seen by normal people
Central staining is too light: Hb synthesis disorder
Hypochromic anemia: iron deficiency anemia, globin production disorder anemia
Loss of central light-stained area (spherical cells): hereditary spherocytosis
large red blood cells
form
Diameter greater than 10μm
occur
Seen in hemolytic anemia, megaloblastic anemia
giant red blood cells
form
Diameter greater than 15μm
occur
Folic acid, VitB12 deficiency: megaloblastic anemia, pernicious anemia
Uneven size of red blood cells
form
The diameter is more than twice the difference
occur
Bone marrow hematopoietic dysfunction and weakened hematopoietic regulation function
Severe proliferative anemia (especially megaloblastic anemia)
changes in the shape of red blood cells
Spherocytes
form
The cell diameter is less than 6.0 μm, the thickness increases, and the central light-stained area disappears, resembling a sphere.
occur
An increase is seen in hereditary spherocytosis (>25%).
Elliptocytes
form
The cells are oval or rod-shaped, with the length at least 3-4 times the width.
occur
Occasionally seen in healthy people, increased in hereditary elliptocytosis (>15%).
Stomatocyte
form
There is a slit in the center of the cells, and the central light-stained area is flat, resembling an open mouth shape or a fish mouth.
occur
The increase is seen in hereditary stomatocytosis (>10%), alcoholism, etc.
Target cells
form
The central part of the cells is darkly stained, the periphery is pale, and the edges are darkly stained, shaped like a shooting target.
occur
The increase is seen in globin production disorder anemia (>20%) and iron deficiency anemia.
sickle cell
It is a crescent-shaped or sickle-shaped red blood cell with a pointed tip due to the polymerization of HbS.
Mainly seen in sickle cell disease (HbS disease).
teardrop cell
Teardrop red blood cells are pear-shaped or teardrop-shaped red blood cells.
Mainly seen in myelofibrosis.
acanthocyte
There are needle-like protrusions on the surface of the cells, with irregular spacing and varying lengths and widths.
When the number of acanthocytes is >25%, it is acanthosis (congenital abetalipoproteinemia).
Serrated red blood cells (echinocytes)
The periphery of red blood cells has a blunt zigzag shape, the protrusions are evenly arranged and of the same size, and the outer ends are pointed.
Membrane lipid abnormalities---seen in liver disease, uremia, etc.
Rouleaux formation of red blood cells
Red blood cells aggregate into strings due to the increase in positively charged globulin and fibrinogen in the blood.
Mainly seen in multiple myeloma and primary macroglobulinemia.
Abnormal hemoglobin content (shading)
normochromic
Seen in normal people
Acute blood loss, aplastic anemia, leukemia
Hypochromic
The physiological light-stained area expands, the staining is light, and Hb is significantly reduced.
Common in iron deficiency anemia, globinogenic anemia, sideroblastic anemia, and certain hemoglobinopathies
Hyperchromic
The physiological light-stained area disappears, the entire RBC is darker, and the Hb content increases
Commonly seen in megaloblastic anemia and spherocytosis.
polychromatic
RBCs are light gray-blue or gray-red, and the cell body is slightly larger.
A small amount of RNA coexists with Hb in the cytoplasm, indicating active bone marrow hematopoietic function.
Various proliferative anemias (especially anemia)
Abnormal structure and arrangement of red blood cells
basophilic stippling cells
Red blood cells with basophilic brown-blue granules in the cytoplasm are immature red blood cells.
It can be seen in anemia with strong bone marrow proliferation, such as megaloblastic anemia; it can also be seen in lead poisoning, and is often used as a screening indicator for the diagnosis of lead poisoning.
Howell-Jolly’s body
The round purple-red bodies contained in red blood cells, the remaining parts after nuclear fragmentation or dissolution, often exist together with the Kapos ring.
Mainly seen in proliferative anemia, such as hemolytic anemia, megaloblastic anemia, erythroleukemia, etc.
Cabot ring
The purple-red thin coil-like structure or "8" shape in the cytoplasm is the remnants of the nuclear membrane, the remnants of the spindle, and the denaturation of lipoproteins in the cytoplasm.
Seen in severe anemia, hemolytic anemia, megaloblastic anemia, lead poisoning, leukemia and after splenectomy.
Reticulocyte test (Ret)
definition
Ret is an immature erythrocyte between late immature erythrocytes and mature erythrocytes. Basophilic substances (ribosomes and RNA) remain in the cytoplasm, which can be stained by certain dyes (such as neomethylene blue or brilliant tar blue). ) Vital staining shows a blue mesh or granular structure, hence its name.
Reference range
aldult
Relative value: 0.005~0.015
Absolute value: (24~84)×109/L
clinical significance
Important indicators reflecting bone marrow hematopoietic function
Determine bone marrow red blood cell production
(1) Increased Ret: Strong bone marrow hematopoiesis
Seen in various proliferative anemias (anemia)
(2)Ret reduction: ineffective red blood cell hematopoiesis
Seen in nonproliferative anemia (aplastic anemia)
Important indicators for observing the efficacy of anemia
Monitoring hematopoietic function after bone marrow transplantation
Bone marrow function monitoring during radiotherapy/chemotherapy
Avoid severe bone marrow suppression
Erythrocyte sedimentation rate measurement
Erythrocyte Sedimentation Rate (ESR)
definition
ESR refers to the distance that red blood cells in isolated anticoagulated whole blood sink at the end of the first hour under certain conditions.
Reference
Factors affecting erythrocyte sedimentation rate determination
subtopic
Plasma Factors: Composition and Proportions of Proteins and Lipids
Accelerate: macromolecular proteins (Fg, Glb, CHOL, TG, etc.)
Slow down: small molecule protein- (Alb, lecithin)
Red blood cells: number, size, shape
Accelerate: Decreased red blood cells
Slow down: increased red blood cells, spherocytosis, etc.
clinical significance
routine screening test
lack of specificity
It is mainly used to observe the dynamic changes of the disease, distinguish functional and organic lesions, identify benign and malignant tumors, etc.
Increased erythrocyte sedimentation rate
Physiologically accelerated erythrocyte sedimentation rate
Acceleration of pathological erythrocyte sedimentation rate
Slowing of erythrocyte sedimentation rate (of little significance)
Polycythemia vera, hypofibrinogenemia, spherocytosis.
Hematocrit determination and red blood cell related parameters
Hematocrit measurement (HCT)
definition
The relative proportion of red blood cells in a given volume of whole blood.
reference interval
adult
Male: 0.40 ~ 0.50L/L
Women: 0.37～0.48L/L
clinical significance
HCT and RBC counts have similar meanings
Reduced HCT is one of the indicators for diagnosing anemia
reason
mean red blood cell index
Mean corpuscular volume (MCV)
Positive, large and small red blood cells
Mean corpuscular hemoglobin content (MCH)
Normochromic, hyperchromic, and hypochromic red blood cells
Mean corpuscular hemoglobin concentration (MCHC)
Reflects the concentration of Hb in RBCs and remains constant in most diseases
Reference
clinical significance
Determination of red blood cell volume distribution width (RDW)
definition
Red blood cell volume distribution width is measured by a hematology analyzer. It is a parameter that reflects the heterogeneity of red blood cell volume in peripheral blood. It is an objective indicator that reflects the uniformity of red blood cell size. It is commonly expressed as the coefficient of variation (RDW-CV).
clinical significance
blood cell histogram
Hematology analyzer detection principle
Blood cells are relatively non-conductive. When the blood cells suspended in the electrolyte solution pass through the counting holes, they can cause changes in the current or voltage inside and outside the holes, forming a pulse signal corresponding to the number and volume of the blood cells, thereby measuring the blood cells. Count and indirectly differentiate cell populations based on volume. This principle is also called the Coulter principle.
Pulse size: cell volume Number of pulses: number of cells
White blood cell levels according to instrument classification can be divided into:
Two groups: granulocytes and lymphocytes
Three groups: large cell group, small cell group and intermediate cells
Five categories: N, L, E, B, M
Five groups reticulocyte counting analyzer
Performance
After treatment with hemolytic agent, white blood cells are counted and grouped according to the principle of electrical impedance.
The role of hemolytic agent:
Rapidly lyse red blood cells
Cause the cytoplasm of white blood cells to leak through the membrane, which is tightly attached to the nucleus or around the granules.
The processed white blood cells have nothing to do with the natural volume. The size of granulocytes containing granules is larger than that of monocytes and lymphocytes without granules.
concept
Histograms are blood cell volume distribution graphics measured by a hemocytometer. These graphics can represent the distribution of cell populations.
Clinical applications of red blood cell histograms
The normal red blood cell histogram is almost a bilaterally symmetrical and narrow normal distribution curve, mainly distributed in the area of 24 fl to 360 fl.
leukocyte
White blood cell test
White blood cell count
White blood cell count reference value
White blood cell differential count
White blood cell normal percentage and absolute value
neutrophils
Neutrophilia
Physiological increase
Daytime differences, late pregnancy, strenuous exercise, after a heavy meal or shower, high temperature or severe cold
Pathological increase
Acute infection (pyogenes), severe tissue damage and massive blood cell destruction, acute massive bleeding, acute poisoning, leukemia, myeloproliferative tumors and some malignant solid tumors, etc.
Neutropenia
Infections (Gram-negative bacteria: typhoid fever, paratyphoid bacilli; certain viral infections), certain blood system diseases (aplastic anemia), physical and chemical factor damage, mononuclear-phagocytic cell system hyperfunction, autoimmune diseases (systemic lupus erythematosus) etc.
Nuclear image changes of neutrophils
Refers to the lobulation status of granulocytes, reflecting the maturity of granulocytes.
Neutrophil nuclear left shift refers to an increase (more than 5%) in the percentage of non-neutrophil lobulated nuclei (neutrophils, promyelocytes, mesomyelocytes, promyelocytes) in peripheral blood.
Neutrophil nuclei shift to the right
When the nucleus of peripheral blood neutrophils has five or more lobes, and the percentage exceeds 3%, it is called right-shifted nucleus.
Common in megaloblastic anemia, pernicious anemia, etc. During the recovery period of inflammation, there may be a transient right shift. If the right shift suddenly occurs during the progression of the disease, the prognosis is often poor.
Abnormal neutrophil morphology
Toxic changes in neutrophils
Condition
Severe infectious diseases, purulent infections, poisoning, malignant tumors, large area burns, etc.
specific
Uneven size (anisocytosis)
toxic granulation
Vacuole formation (vacuolizatien)
Döhle bodies
degeneration of nucleus
clinical significance
These three morphological abnormalities can appear individually or simultaneously. Seen in serious infectious diseases, such as purulent infection, sepsis, malignant tumors, poisoning and large-area burns, etc.
giant multilobulated neutrophils
It is more common in megaloblastic anemia or after treatment with antimetabolite drugs.
eosinophils
Eosinophilia
Allergic diseases (E>10%), parasitic diseases (E>10%), blood diseases, certain malignant tumors, certain infectious diseases (scarlet fever), etc.
eosinophilia
Early stage of typhoid fever and paratyphoid fever, major surgery, burns and other stress states.
basophils
basophilia
①Allergic diseases: allergic colitis, hypersensitivity to inhalants, erythema and rheumatoid arthritis.
②Hematological diseases: chronic myeloid leukemia, basophilic leukemia, myelofibrosis.
③Malignant tumors: metastatic cancer
Basophenopenia: not clinically significant
Lymphocytes
lymphocytosis
①Infectious diseases: mainly viral infections (rubella, measles, chickenpox, infectious mononucleosis)
②Mature lymphocytic tumors: mature lymphocytic leukemia and some lymphomas
③The recovery period of acute infectious diseases
④Transplant rejection: Graft versus host reaction (GVHR)
lymphopenia
Application of adrenocortical hormones, alkylating agents, radiation, immunodeficiency diseases, etc.
Reactive lymphocytes (atypical lymphocytes)
specific
Type I (foam type)
Type II (irregular type)
Type III (naive type)
clinical significance
It is more common in infectious diseases (infectious mononucleosis caused by Epstein-Barr virus infection, more than 10%), epidemic hemorrhagic fever, drug allergies, etc.
monocytes
Pathological increase in monocytes
Certain infections: such as infective endocarditis, malaria, kala-azar, etc.
Certain blood diseases: such as monocytic leukemia, agranulocytosis recovery period, myelodysplastic syndrome, etc.
Monocytopenia
Mostly of no clinical significance
White blood cell volume distribution histogram
distributed
White blood cells: 35 ~ 450 fl
Small cell population: 35 ~ 90 fl, mainly lymphocytes
Intermediate cell population: 90 ~ 160 fl, including monocytes, eosinophils, basophils, blastocytes or leukemia cells.
Large cell population: more than 160 fl, mainly neutrophils.
Three-group blood analyzer
Normal white blood cell classification pattern diagram (histogram)
platelets
Platelet test
PLT is the most commonly used primary screening indicator to judge hemostatic and anticoagulant function.
normal reference range
(100~300)×109/L. In anticoagulated blood, platelets are scattered individually. In non-anticoagulated blood, platelets are often distributed in groups of 3 or 5.
platelet count
Thrombocytopenia
PLT is less than 100×109/L
common
(1) Platelet production disorder: aplastic anemia
(2) Damage or increased consumption: ITP, SLE, DIC
(3) Abnormal distribution: splenomegaly due to liver cirrhosis
thrombocytosis
PLT exceeds 400×109/L
common
(1) Primary: essential thrombocythemia
(2) Reactivity: acute infection (mostly below 500×109/L)
Mean platelet volume (MPV)
definition
The average volume of a single platelet.
Increase
Those with increased platelet destruction but good bone marrow compensatory function;
After the suppression of hematopoietic function is relieved, the increase in MPV is a precursor to the recovery of hematopoietic function.
Decreased: Poor bone marrow hematopoiesis
Platelet distribution width (PDW)
definition
Dispersion of platelet volume size.
Increased: Platelet size disparity occurs in acute and chronic myeloid leukemia and megaloblastic anemia.
platelet histogram
Principle of red blood cell and platelet detection---the same analysis system
Since platelets and red blood cells have obvious differences in volume, based on the principle of electrical impedance, a limited threshold can be used to distinguish the signals detected simultaneously by the two, and the number and volume of red blood cells and platelets can be calculated based on different thresholds.
Clinical applications of platelet histograms
The normal platelet histogram shows a left-skewed distribution, mainly in the range of 2 fl to 20 fl, and mainly concentrated in 2 fl to 15 fl.
Section 2 Hemolytic Anemia Detection (HA)
definition
Hemolysis: The process of premature destruction of red blood cells without aging
Classification
Poverty alleviation is classified according to causes and pathogenesis
By location: intravascular---extravascular (destroyed within the spleen and liver mononuclear phagocytic system)
process
Hemoglobin metabolism process after intravascular hemolysis:
The process of extravascular hemolysis of hemoglobin:
Laboratory testing
Initial screening of general laboratory projects
1. Blood routine: RBC, Hb, HCT, Ret
2. Liver function: total bilirubin indirect bilirubin
3. Urine routine: hemoglobinuria (strong tea-like or soy sauce-like)
Hemolytic anemia project screening
Mainly related to whether there is increased destruction of red blood cells and shortened life span
project
Plasma free Hb
Plasma free hemoglobin determination (plasma free hemoglobin)
[Reference value]: <50mg/L
[Significance]: It is significantly increased when intravascular hemolysis occurs, but does not increase when extravascular hemolysis occurs.
Serum haptoglobin (Hp)
[Reference value]: 0.7～1.5 g/L
[Clinical significance]:
(1) Reduced Hp: indicates the presence of hemolysis, and is significantly reduced when intravascular hemolysis occurs
(2) Increased Hp: indicates acute and chronic infections, malignant tumors, rheumatoid arthritis, SLE, etc.
(3) Identify intrahepatic and extrahepatic obstructive jaundice
Significant reduction or absence of obstructive jaundice within the liver (intrahepatic bile ducts)
Normal or increased extrahepatic obstructive jaundice (extrahepatic bile duct)
Plasma methemoglobin albumin
Plasma methemalbumin test
Free hemoglobin in plasma is oxidized to methemoglobin, which is then decomposed into methemoglobin, which combines with albumin to form methemoglobin.
【Result Judgment】Negative
[Clinical significance] It is seen in severe intravascular hemolysis caused by various reasons and is an important indicator for detecting intravascular hemolysis. A negative test cannot exclude intravascular hemolysis.
Hemosiderinuria test (Rous test)
Renal tubular epithelial cells absorb hemoglobin and metabolize it into hemosiderin. When the cells are shed into the urine, the iron ions generate blue ferric ferricyanide in the acidified low-ferricyanide solution. Under the microscope, dark blue material may appear in the urine sediment, which is considered positive.
【Result Judgment】Negative
[Clinical significance] It is seen in chronic intravascular hemolysis and is common in PNH. The positivity can last for several weeks and is of great significance in the diagnosis of chronic intravascular hemolysis.
Red blood cell lifespan
Red blood cell life span measurement
Principle: 51Cr isotope labeling
Reference value: half-life 25~32 days
Clinical significance: Anemia is when the half-life of RBC is <15 days, indicating the presence of hemolysis.
Defect detection
Causes of poverty
Detection of Cell Membrane Defects: Red Blood Cell Osmotic Fragility Test
【principle】
It measures the resistance of red blood cells to hemolysis by hypotonic sodium chloride at different concentrations. Mainly depends on the ratio of red blood cell surface area to volume. Large surface area and small volume make it highly resistant to hypotonic salt water (i.e. less brittle). On the contrary, the resistance is less (that is, the brittleness is greater).
【Reference 】
Beginning of hemolysis: 0.42% ~ 0.46% (4.2 ~ 4.6g/L) NaCL
Complete hemolysis: 0.28% ~ 0.34% (2.8 ~ 3.4g/L) NaCL
【Clinical significance】
(1) Increased fragility: hereditary spherocytosis (hemolysis begins at 5.2g/L, or even begins at 6.8g/L)
(2) Reduced fragility: microcytic anemia-thalassemia, iron deficiency anemia
Red blood cell enzyme deficiencies: methemoglobin reduction test
[Principle] Adding sodium nitrite to the blood being tested changes methemoglobin into ferrous hemoglobin. When the G6PD content and activity are normal, the amount of NADPH generated by the pentose phosphate metabolic pathway is sufficient to complete the above reduction reaction.
【Reference 】
Methemoglobin reduction rate is >75%; methemoglobin 0.3-1.3g/L.
【Clinical significance】
Reduction: In patients with favismosis and primaquine-type drug-induced hemolytic anemia, the methemoglobin reduction rate is significantly reduced due to G6PD deficiency.
Detection of Abnormal Hemoglobin
Normal: The hemoglobin molecule is composed of 4 globin peptide chains (2 pairs) and 4 heme
Hemoglobin electrophoresis detection
A normal adult electrophoresis pattern shows four bands, the most of which is HbA, a small amount of HbA2, and then two or two less of non-hemoglobin components (NH1, NH2) in red blood cells.
【Clinical significance】
Abnormal hemoglobin zones are seen in thalassemia (HbA2 ↑), iron deficiency anemia and sideroblastic anemia (HbA2 ↓).
Detection of autoimmune hemolytic anemia: antiglobulin test (Coombs’ test)
【principle】
The incomplete antibody IgG molecules that have been bound to the corresponding antigens on red blood cells are smaller and cannot connect two adjacent red blood cells and can only bind to one red blood cell antigen. Anti-human globulin antibodies are complete antibodies that can bind to multiple incomplete antibodies on the surface of red blood cells. The combination causes red blood cells to connect to each other and cause agglutination, which is called a positive antiglobulin test.
【Clinical significance】
Positive: Hemolytic disease of the newborn, autoimmune hemolytic anemia, SLE, rheumatoid arthritis
PNH detection: acidification hemolysis test (Ham test)
【principle】
Red blood cells with defective membrane proteins are more sensitive to complement. In weakly acidic serum (pH 6.6~6.8), red blood cells undergo hemolysis after incubation at 37°C.
【Clinical significance】
Negative in normal people, positive in paroxysmal nocturnal hemoglobinuria (PNH).
Bone marrow cytology testing
Clinical application
1. Diagnose hematopoietic system diseases---such as various types of leukemia
Assist in diagnosing certain diseases---such as iron deficiency and anemia
Improve the diagnosis rate of certain diseases---such as Plasmodium and Kala-azar
2. Indications and contraindications
Indications: Abnormalities in peripheral blood cell composition and morphology, unexplained fever, observation of efficacy after chemotherapy, and bone marrow specimen examination.
Contraindications: Bleeding disorders, pregnant women in late pregnancy.
Methods and content
(1) Visual inspection
Observe whether the collection of bone marrow specimens and smear preparation are satisfactory
Small bone marrow granules can be seen in good bone marrow films.
(2) Low-magnification examination
Determine the degree of bone marrow hyperplasia. Reflected by the amount of nucleated cells, it is divided into five levels.
Observe megakaryocytes
Pay attention to any abnormal cells
Determine the degree of bone marrow hyperplasia
Reflected by the number of nucleated cells. Generally, the ratio between nucleated cells and mature red blood cells is observed under low magnification. Normally 1:20.
It is usually divided into five levels: hyperplasia is extremely active, obviously active, active, reduced, and obviously reduced.
(3) Oil mirror inspection
Classification and counting of nucleated cells: Continuously classify and count 200 or 500 nucleated cells, count them according to different series of cells and different developmental stages, and calculate the percentage of cells in each stage. Then total the total number of granulocytes and immature erythrocytes to calculate the granulocyte-to-red ratio (G:E). Normally, it is 2~4:1.
Observe cell morphology: When performing classification and counting, also observe whether the morphology is normal, whether there are abnormal cells, parasites, etc.
(4) Bone marrow image analysis and report
result
Cytochemical staining of blood cells
definition
Cytochemical staining is based on cell morphology and based on the principle of chemical reaction. It uses bone marrow smears for fixation, chemical reaction color development, counterstaining and other procedures, and then observes the chemical composition and changes of cells under a light microscope. Item inspection method.
effect
To study the chemical components in blood cells, their content and distribution are different. Therefore, the use of cytochemical staining is helpful for the identification of blood cell types, as well as for the diagnosis and differential diagnosis of certain blood diseases, observation of efficacy, and exploration of pathogenesis. value.
Dyeing methods (inductive comparison)
Peroxidase (POX) staining
principle
The cytoplasm of granulocytes and monocytes contains peroxidase (POX), which can catalyze hydrogen peroxide to release new ecological oxygen, oxidize the colorless receptor tetramethylbenzidine, and generate blue tetramethylbenzidine. benzidine blue, which is then combined with sodium nitrosoferricyanide to form stable blue particles that precipitate in situ in the cytoplasm.
Clinical significance - identifying types of acute leukemia
In acute myeloid leukemia, most leukemia cells show strong positive reactions
In acute monocytic leukemia, there is a weak positive or negative reaction
acute lymphoblastic leukemia negative
Neutrophil alkaline phosphatase (NAP) staining
principle
Alkaline phosphatase (NAP) in the cytoplasm of neutrophils in the mature stage can hydrolyze sodium naphthol phosphate in the matrix solution in a buffer solution with a pH of 9.2 to 9.8, releasing phosphoric acid and naphthol. Coupled with diazonium salts to form insoluble colored azo dyes, which precipitate in the cytoplasm.
The clinical significance of NAP
Chloroacetate AS-D naphthol esterase staining
Acid phosphatase (ACP) staining
α-Naphtyl acetate esterase staining and sodium fluoride inhibition assay
Glycogen staining
iron stain
principle
The iron in the cells reacts in the acidified low-ferricyanide solution to produce blue iron ferricyanide (Prussian blue), which is located in the iron-containing parts.
Extracellular iron: stored iron within the monocyte-phagocytic system in bone marrow granules
Intracellular iron: iron in red blood cells, sideroblasts
Example
clinical significance
Iron deficiency anemia: decreased extracellular and intracellular iron
Non-iron deficiency anemia: increased extracellular iron
Sideroblastic anemia: increased sideroblasts and ringed sideroblasts
Sudan Black B (SB) dyeing
Diagnostic indicators for the cause of poverty
Section 4 Blood type identification and cross-matching test
blood group system
red blood cell blood group system
ABO blood group system
blood group antigens
Antibody classification
Natural Antibodies-IgM (Complete Antibodies)
Immunity antibody-IgG (incomplete antibody)
Blood is divided into four types based on the presence of antigen A and antigen B on the red blood cell membrane.
Subtype
Subtypes refer to blood types that have the same blood group antigen but have certain differences in antigen structure, performance or number of antigen epitopes.
Classification
Subtype A:
A 1 , A 2 , A 3 , AX and A M etc.
The main subtypes A1 and A2 account for 99.9% of all type A blood.
AB subtype: A1B, A2B two subtypes
my country is dominated by A1B subtypes
Subtype B: rare and named differently, generally called subtype B or weak type B.
The significance of subtype detection
Prevent misdetermination of blood types and avoid transfusion reactions
① Blood transfusion between A1 and A2
② Subtypes have weak antigenicity and are easily missed or misidentified. When a subtype is suspected, in addition to using anti-A and anti-B sera for typing, the red blood cells should also be reacted with type O serum. Reverse typing can also be used to determine the subtype. evidence.
identification
principle:
A antigen anti-A antibody
B Antigen Anti-B Antibody
method:
Positive typing: Use standard anti-A and anti-B sera to identify antigens on RBCs
Countertyping: Identification of antibodies in serum using RBCs of known blood type
Slide agglutination method: positive stereotype (tested RBC standard anti-A/B serum)
Slide agglutination method: reverse typing (tested serum standard RBC)
Identification meaning
Ensure the safety of blood transfusion: compatible blood transfusion, compatible blood transfusion.
Hemolytic disease of the newborn (ABO-HDN): the first child, the mother is type O and the fetus is type A or type B.
Organ and tissue transplantation: ABO blood group incompatibility can accelerate graft rejection.
Others: Presumption of kinship, forensic trace testing.
Rh blood group system
System composition:
(1) Antigens: There are mainly five types: D, C, c, E, and e, with D antigen being the strongest.
(2) Antibodies: five types of anti-D, C, c, E, and e, anti-D is the most common
Rh antibodies are mainly incomplete antibodies.
leukocyte antigen system
platelet blood group system
Chapter 1 Introduction
1. The concept of experimental diagnosis
laboratory diagnosis
It is a clinical diagnostic method based on laboratory test results or data, combined with other clinical data, and after comprehensive analysis, used in clinical diagnosis, differential diagnosis, disease observation, efficacy monitoring and prognosis judgment.
status
It is an important bridge between basic medicine and clinical medicine.
Main content and application scope
Main contents of experimental diagnosis
clinical hematology tests
clinical biochemistry examination
clinical immunological examination
Clinical etiological examination
Body fluid and excrement examination
Other examinations: Chromosome examination for genetic diseases, genetic examination
Application scope of experimental diagnosis
(1) Serving clinical medical work
Disease diagnosis and differential diagnosis, observation of therapeutic effects and prognosis judgment
(2) Provide a basis for carrying out prevention work
(3) Conduct social census
(4) Carry out health consultation
2. Quality system and influencing factors of experimental diagnosis
Perfect quality assurance system
Purpose: To detect errors in the analysis process, control relevant aspects of the analysis, and ensure that the results are accurate and credible.
Classification
In-house quality control
Room quality control
Laboratory quality system
Factors affecting experimental diagnosis
1. Pre-laboratory factors
More than 60% of the reasons for errors in test results come from the laboratory, mainly the collection and processing of specimens.
2. Laboratory factors
Specimen quality and processing, instruments and reagents, personnel skills and knowledge, operating techniques and methods, quality control materials and standards, safety and cost, etc.
3. Post-laboratory factors
Inspection records, result writing, information input and transmission, laboratory and clinical communication, etc.
3. Collection and processing of patient specimens
patient specimen
Blood sample examination is the most important
blood, urine, feces
Various secretions
Various physiological and pathological body fluids
4. Clinical application and evaluation of experimental diagnosis
Correctly choose laboratory inspection items
in principle
Targeted
effectiveness
Economy
timeliness
Evaluation indicators for diagnostic tests
diagnostic sensitivity
diagnostic specificity
diagnostic accuracy
5. Experimental diagnosis reference range, medical decision level and critical value
Reference range
Various test items have judgment standards, the so-called reference values or reference ranges, which are used to measure whether the results of the tested specimens are abnormal.
Medical Decision Level (MDL)
By observing whether the measured value is higher or lower than these limits, it can play a role in excluding or confirming disease diagnosis, grading or classifying certain diseases, or making an estimate of prognosis.
critical value
Critical values refer to when certain test results are abnormal and exceed a certain threshold, which may endanger the patient's life and the doctor must deal with it urgently. This is called critical value.