Platelet test items

The platelet test program is a quantitative and qualitative analysis of platelets in the blood for the diagnosis of platelet abnormalities. The basic functions of platelets are adhesion, aggregation, secretion, procoagulant, and blood clot retraction. Through these functions, the initial hemostasis of the normal human body is maintained. Bleeding diseases caused by these abnormal functions include hereditary and acquired, and in some diseases, platelet dysfunction and number are reduced. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: Do not eat too greasy, high-protein foods the day before, and avoid heavy drinking. The alcohol content in the blood directly affects the test results. After 8 pm on the day before the medical examination, you should fast. Normal value 100 × 109 ~ 300 × 109 / L. Clinical significance Abnormal result (1) PLT-platelet count Reduced thrombocytopenia, such as aplastic anemia, acute leukemia, etc. Excessive destruction such as primary thrombocytopenic purpura. Excessive consumption is seen in diffuse intravascular coagulation, thrombotic thrombocytopenia, etc. Thrombocytopenia caused by abnormal platelet distribution. When the spleen is large, more than 90% of the blood platelets in the blood are stored in the spleen, resulting in a mild to moderate decrease in platelets in the blood. Pseudo-platelet-reducing blood samples using EDTA anticoagulants can induce a significant reduction in platelets in a small number (0.1%); when large platelets are present in the blood, they are pseudo-reduced because they cannot be counted. These two cases can be found in giant platelet syndrome. Note that the venous blood count platelet results are stable and the interference factors are small. Peak blood sampling is likely to cause platelet activation, aggregation and the like. (2) MPV-average platelet volume Identification of thrombocytopenia When spinal cord hematopoietic function is impaired, both MPV and PLT reduce platelet destruction such as ITP, and MPV can increase; if splenectomy, both MPV and PLT can be elevated. Bone marrow hematopoietic function When evaluating hematopoietic function, MPV and PLT showed a continuous decrease trend, and the function was severely inhibited, and the MPV was smaller. When hematopoietic function was restored, the increase of MPV was higher than that of PLT. MPV increases giant platelet syndrome and the like. Reactive thrombocytosis, such as infection, surgery, etc., MPV is normal. (3) PCT-platelet specific volume: Any increase in PLT and/or MPV can lead to an increase in PCT, such as primary and secondary thrombocytosis. (4) PDW-platelet volume distribution width: the increase is meaningful, the platelet volume is more uniform, and the PDW is larger. The clinical significance is to be further studied. (5) P-LCR-large platelet ratio Platelets can be divided into small, medium, large and giant. Large platelet increase is mainly seen in idiopathic thrombocytopenic purpura; giant platelet increase is seen in giant platelet syndrome. The people who need to be examined have weak, weak, sleepy, pale skin, mucous membranes, palpitations, dizziness, headache, tinnitus, vertigo, inattention, and lethargy. Low results may be diseases: thrombosis, pregnancy with idiopathic thrombocytopenic purpura, high leukemia results may be disease: aplastic anemia considerations Inappropriate people: People with a significant tendency to bleed. Taboo before the test: Do not eat too greasy, high-protein foods the day before the test, to avoid heavy drinking. The alcohol content in the blood directly affects the test results. After 8 pm on the day before the medical examination, you should fast. Requirements for examination: When taking blood, you should relax your mind to avoid the contraction of blood vessels caused by fear and increase the difficulty of blood collection. Inspection process (I) Determination of platelet release granules and activation function The platelet cytoplasm contains α2 particles, dense particles, lysosomes, etc., and when the attractant is added, it causes the release of these particles, a process called platelet release. It can be judged by measuring 5HT or adenosine. The 5HT assay has two types of fluorescence spectrophotometry and isotope assay. The release of alpha particles is primarily determined by plasma beta-platelet globulin (βTG) and platelet factor 4 (PF4). PF4 and βTG are specific proteins contained in platelet alpha particles, and the assay is carried out by ELISA. Its increase indicates that platelets are activated and released, and it is also seen in hypercoagulable states and thrombotic diseases. Platelet a granule membrane protein 140 (GMP140), also known as Pselection (Pselection), is itself a relatively reliable indicator of platelet activity. The amount of GMP140 in plasma or platelet membrane can be quantified by monoclonal antibodies against GMP140, respectively. Its elevation represents thrombotic diseases, autoimmune diseases [such as systemic lupus erythematosus, idiopathic thrombocytopenic purpura (ITP)], and metabolic diseases (such as diabetes complicated by peripheral vascular disease). GMP140 is considered to be the "gold standard" for the response to platelet release. However, to date, the correlation between these markers and platelet aggregation rates has been known, especially in the case of various antiplatelet drug therapies. However, some experiments have shown that platelet degranulation is quickly separated from GMP140 but still exists in the blood circulation and is active. Whole blood flow cytometry (FCM) has made great progress in the detection of platelet function, which can be used for the diagnosis of platelet dysfunction, the quantification of surface receptor density, the detection of activated platelets, and the monitoring of platelet response to activators. Monitoring platelet metabolism, monitoring for antiplatelet therapy, monitoring of products in thrombocytopenia, platelet-associated immunoglobulin G, platelet survival, and signal transduction. FCM can detect activated platelets in the blood sensitively and specifically by specific platelet antibodies and dyes using very few blood samples, and evaluate its function. At the same time, FCM can be used to predict cardiovascular disease by detecting activated platelet surface markers. Current FCM has been applied to platelet hyperreactive diseases (heart, cerebral thrombosis), platelet hyporeactive disease (platelet weakness), bone marrow transplantation efficacy assessment (neonatal platelet), thrombocytopenia (ITP) and GPIIb/IIIa antagonists Treatment monitoring and other fields. However, due to the high price of the flow cytometer, the detection cost is high, and the operation of the instrument is complicated; in order to avoid activation in vitro, the blood sample needs to be treated within 45 minutes, and cannot be set for a long time; in addition, the flow cytometer only detects the platelet function in the circulation, and the βTG is detected. PF4 and thromboxane A2 (TXA2) can reflect the activation of platelets on the vessel wall and the functional indicators of newly cleared platelets cannot be detected. These factors further define their application. (B) Determination of AA metabolites Determination of plasma thromboxane B2 (thromboxane B2, TXB2). The main active product of platelet AA metabolism is TXA2, which is very unstable and quickly converts itself to stable TXB2. TXB2 is generally reflected by measuring TXB2. The TXB2 assay was performed by ELISA: the enzyme-labeled reaction plate was coated with TXB2BSA, the test plasma and TXB2 antibody were added, and TXB2 was coated, and the sample TXB2 was competitively bound to a certain amount of antibody, and the second antibody and the substrate were added. The color reaction determines the TXB2 content of the sample. It is worth noting that the continuous increase in TXB2 levels not only reflects the unsuppressed COX1 activity of platelets, but also reflects the level of TXA2 produced by non-COX1 pathways. Therefore, TXB2 levels are the most valuable method for detecting antiplatelet therapy resistance. (C) determination of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) cAMP and cGMP are second messenger systems that regulate platelet function. When cAMP production is reduced, platelets undergo aggregation reaction, and when cAMP production increases, platelets do not undergo aggregation reaction; on the contrary, platelets do not undergo aggregation reaction when cGMP production is decreased, and platelet aggregation occurs when cGMP production increases. Reference range (ELISA): cAMP is (1518 ± 724) pmol per 109 platelets, and cGMP is (046 ± 024) pmol per 109 platelets. (4) Other platelet tests 1. Detection of platelet leukocyte conjugate: GMP140 on the surface of platelets can specifically bind to GMP140 glycoprotein ligand 1 (PSGL1) on the surface of leukocytes. When platelets and leukocytes are activated, both GMP140 and PSGL1 increase, reflecting an increase in the binding of platelets to leukocytes. This is of great significance for the diagnosis and research of thrombosis. 2. Detection of platelet microparticles (PMP): After activation of platelets, vesicles are formed by budding or PMP is formed by pseudo-foot fracture. PMP is small (01 to 10 μm in diameter) but has a complete membrane structure and function. FCM detects the reference range of PMP: (58 ± 15) per 104 platelets. Increased PMP reflects platelet destruction or activation. Elevated PMP represents a thrombotic disease; reduced in congenital AA metabolic disorders, taking aspirin, sulfinpyrazone, imidazole and other drugs. 3. New markers of platelet activation: including platelet procoagulant activity, microparticles and mononuclear platelet aggregation. Many current experiments have shown that in stable angina, coronary intervention, acute myocardial infarction, etc., mononuclear platelet aggregates are more sensitive than GMP140 on the surface of platelets in terms of markers of platelet activation in vivo. Not suitable for the crowd 1. Patients who have taken contraceptives, thyroid hormones, steroid hormones, etc., may affect the results of the examination and prohibit patients who have recently taken the drug history. 2, special diseases: patients with hematopoietic function to reduce disease, such as leukemia, various anemia, myelodysplastic syndrome, etc., unless the examination is essential, try to draw less blood. Adverse reactions and risks 1, subcutaneous hemorrhage: due to pressing time less than 5 minutes or blood draw technology is not enough, etc. can cause subcutaneous bleeding. 2, discomfort: the puncture site may appear pain, swelling, tenderness, subcutaneous ecchymosis visible to the naked eye. 3, dizzy or fainting: in the blood draw, due to emotional overstress, fear, reflex caused by vagus nerve excitement, blood pressure decreased, etc. caused by insufficient blood supply to the brain caused by fainting or dizziness. 4. Risk of infection: If you use an unclean needle, you may be at risk of infection.