Blood Cell Examination
From WikiLectures
Complete blood count[edit | edit source]
CBC is a very common screening examination taken at every admission to hospital, as well as in suspected infectious or hematologic disease.
CBC includes:
- White Blood Cells (WBC or Leu) + "differential" – i. e. the percentage of Lymphocytes, Monocytes and Neutrophilic, Basophilic and Eosinophilic granulocytes.
- Red Blood Cells (RBC pr Ery).
- RBC parameters (volume, Hb content and concentration per cell).
- Hemoglobin (Hb) and Hematocrit (Hct).
- Platelets (Pt or Thr) .
Workflow and used methods[edit | edit source]
- Blood is taken by a phlebotomist to a tube with EDTA and sent into laboratory.
- Number of cells is counted by the principle of flow cytometry. Flow cytometry is able to determine not only the number of cells in each type, but also volumes of cells. Certain abnormal cells might be identified abnormally (schistocytes, non-mature forms of leucocytes). If presence of abnormal cells is suspected, manual counting under microscope should be performed.
- Hb concentration is determined by absorption spectrophotometry (colorimetry).
- Hct is determined after centrifugation of the sample as a ratio (percentage) of packed cell volume (RBC + WBC + Plt) to whole volume of blood.
- Other RBC parameters (MCV, MCH, MCHC) are calculated by simple formulae.
Physiological count[edit | edit source]
| men | women | Units | |
|---|---|---|---|
| Ery: | 5±0.7 | 4.6±0.7 | 106 /µL (× 1012 /L) |
| Hb: | 150±20 | 140±20 | g/L (also expressed in g/dL) |
| Hct: | 0.46 ±0.06 | 0.43±0.06 | (or × 100 in %) |
- MCV (mean corpuscular volume) = Hct /Ery = 90±5 fL;
- divides anemia into microcytic, normocytic and macrocytic/megaloblastic.
- MCH (MC hemoglobin) = Hb/Ery =31±3 pg;
- divides anemia into hypochromic and normochromic.
- MCHC (MC hemoglobin concentration) = MCH/MCV = Hb/Hct = 34±3 g/dL.
- B-reticulocytes 0.3–1.8%;
- generally divides anemia into those of insufficient production and those of icreased loss.
- B-Leu: 4 000–10 000/µL;
- (child – about 25 % more; toddler – about 50% more).
- neutrophilic granulocytes 30–85% (children less).
- lymphocytes 15–50% or 1500–4000/µL (children more – up to 10,000).
- monocytes 1–12%
- eosinophilic granulocytes 3±3%
- basophilic granulocytes 1±1%
- B-Plt 150,000–350,000/µL
Nomenclature of changes from physiological values[edit | edit source]
| Type of Cell | Increase | Decrease |
|---|---|---|
| Red Blood Cells (RBC) | erythrocytosis or polycythemia | anemia |
| White Blood Cells (WBC) | leukocytosis | leukopenia |
| lymphocytes | lymphocytosis | lymphocytopenia |
| granulocytes | granulocytosis | granulocytopenia or agranulocytosis |
| neutrophils | neutrophilia | neutropenia |
| eosinophils | eosinophilia | eosinopenia |
| Platelets | thrombocytosis | thrombocytopenia |
| All cell lines | — | pancytopenia |
