Red blood cell distribution width (RDW)

The red blood cell volume distribution width (RDW) is an index that measures the dispersion of red blood cell volume by the width of the red blood cell histogram distribution. The blood cell analysis includes this item. Both iron deficiency anemia (IDA) and mild thalassemia (light thalassemia) are small cell anemia. It is difficult to distinguish between the two by MCV alone. IDA is a small cell heterogeneous anemia, and the thalassemia is a small cell homogeneity. Anemia, RDW increases at IDA, but RDW increases rarely during thalassemia. Therefore, if MCV, MCH decreases, and RDW is normal, IDA is unlikely. Therefore, using MCV with RDW, IDA can be identified. The purpose of light thalassemia. Basic Information Specialist classification: cardiovascular examination classification: blood examination Applicable gender: whether men and women apply fasting: fasting Tips: It is not advisable to transfuse blood before examination, and it is not suitable for strenuous exercise. Normal value The normal reference value is <0.15. Clinical significance Abnormal results: 1. Anemia, small cell uniformity (MCV ↓ RDW normal). 2. Anemia, small cell heterogeneity (MCV↓RDW↑). 3. Anemia, positive cell homogeneity (MCV normal, RDW normal). 4. Anemia, positive cell heterogeneity (MCV normal RDW↑). 5. Anemia, large cell homogeneity (MCV ↑ RDW normal). 6. Anemia, large cell heterogeneity (MCV↑RDW↑). 7. Iron deficiency anemia (IDA) and mild thalassemia (light thalassemia) are both small cell anemia. It is difficult to distinguish the two with MCV alone. IDA is a small cell heterogeneous anemia, and the thalassemia is a small cell. Unipolar anemia, RDW increased at IDA, but RDW increased rarely during thalassemia. Therefore, if MCV, MCH decreased, and RDW is normal, IDA is unlikely, so MCV can be used to identify RDW. IDA and the purpose of light thalassemia. Precautions (1) Various types of blood cell counters, especially imported instruments, most of which require heparin intravenous anticoagulation, but most hospitals use peripheral blood, so the normal blood in the area should be investigated before applying the counter. Reference. (2) When collecting blood, care should be taken to avoid mixing the cotton fibers into the suspension to prevent the counting of the holes from being inaccurate. (3) Pay attention to check the power supply, voltage, and inspection preparation before starting the machine. (4) The diluent should be kept between 18 and 30 ° C, the temperature is below 18 ° C, and the cell counting accuracy is reduced. Inspection process Blood is drawn and detected by a professional inspection instrument, often expressed by the coefficient of variation (CV%) of the measured red blood cell volume. Not suitable for the crowd Have a coagulopathy such as hemophilia. Adverse reactions and risks Subcutaneous hemorrhage: subcutaneous hemorrhage due to less than 5 minutes of compression time or blood draw technique.