低血球計數的診斷 – 安健腫瘤治療中心低血球計數的診斷
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How are low blood counts diagnosed?
A test called the complete blood count (CBC) is used to determine whether your blood counts are low. The CBC measures the levels of the three basic blood cells: red, white, and platelets. In the United States, the CBC is typically reported in the format shown below. If your blood counts fall outside of the normal range, which is shown in the "Reference interval" column, their values will be reported in the “Flag” column with an ‘L’ for low and an ‘H’ for high. The example CBC below shows that white blood cells, red blood cells, and platelets are all low.
Result column: The result column shows counts that fall within the normal range. Flag column: The flag column shows counts that are lower (“L”) or higher (“H”) than the normal range. Reference interval (or reference range) column: The reference interval shows the normal range for each measurement for the lab performing the test. Different labs may use different reference intervals. White blood cells: White blood cells help protect individuals from infections. The above CBC report shows that the patient’s total white cell count is 1.5, which is lower than the normal range of 4.0-10.5. The low white cell count increases the risk of infection. Differential: This portion of the CBC shows the counts for the 5 main kinds of white cells, either as percentages (the first 5 counts), or as the absolute number of cells (the second 5 counts).
Absolute neutrophil count: Neutrophils are the main white blood cell for fighting or preventing bacterial or fungal infections. In the CBC report, neutrophils may be referred to as polymorphonuclear cells (polys or PMNs) or neutrophils. The absolute neutrophil count (ANC) is a measure of the total number of neutrophils present in the blood. When the ANC is less than 1,000, the risk of infection increases. The ANC can be calculated by multiplying the total WBC by the percent of polymorphonuclear cells. For example, this patient’s ANC is 0.34, which equals (WBC) 1.5 x 23%. Red blood cells: Red blood cells carry oxygen from the lungs to the rest of the body. The above CBC report indicates that the patient has a red cell count of 3.5, which is lower than the normal range of 4.70-6.10, and therefore, shown in the flag column. Hemoglobin (Hb or Hgb): Hemoglobin is a protein in the red cell that carries oxygen. The above CBC report indicates that the patient’s Hb count is 10.8, which is below the normal range of 14.0-18.0. The hematocrit (HCT), another way of measuring the amount of Hb, is also low. This means that the patient has mild anemia and may be starting to notice symptoms. These three ranges will vary depending on age and gender. For women, they will be lower than those shown here. For example, the Hb reference interval for a woman is 12.0-16.0. Platelets: Platelets are the cells that form blood clots that stop bleeding. The above CBC report indicates that the platelet count for this patient is normal.
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