Complete Blood Count

On April 16, 2010, in Tests, by Andrea

One of the most common, and yet most confusing blood tests ordered.  Lots of numbers, letters, and little to explain it all.

This is known as a CBC.  It’s a basic look at the cells that make up your blood cells, along with the specific components in them.  It’s a critical component for knowing current iron status.

Ranges given are from MY laboratory ranges.  Yours may vary slightly.  Adapt as needed.  My ideals are simply that – my ideals.

The CBC normally includes:

  • Red blood cells – number of red blood cells given as an absolute number per liter; Range: 3.5-6.0 X10^12/L
    • Mean corpuscular volume  or “mean cell volume” (MCV) - measure of the average red blood cell volume (i.e. size); in patients with anemia, this measurement classifies as either microcytic (MCV below normal), normocytic (MCV within normal range), or macrocytic anemia (MCV above normal); in pernicious anemia (macrocytic), normal range is 80-100; MCV can range up to 150 fL; B12 and/or folic acid deficiency has also been associated with macrocytic (high MCV) anemia; most common reasons for microcytic anemia are iron deficiency, thalassemia, or chronic disease; in iron deficiency anemia (microcytic anemia), it can be as low as 60-70 fL; in thalassemia, MCV may be low without being iron deficient; Range: 80.0-100.0 fL
    • Mean corpuscular hemoglobin or “mean cell hemoglobin” (MCH) – the average mass of hemoglobin per red blood cell; MCH is diminished in hypchromic anemias; Range: 26.0-32.0 pg
    • Mean corpuscular hemoglobin concentration (MCHC) – measure of the concentration of hemoglobin in a given volume of packed red blood cells; diminished (“hypochromic”) in microcytic anemias and normal (“normochromic”) in macrocytic anemias (due to larger cell size, though, the hemoglobin amount, or MCH is high, the concentration remains normal); MCHC is high (“hyperchromic”) in hereditary disorders; Range: 32.0-36.0 g/dL
    • Red blood cell distribution width (RDW or RCDW) – measure of the variation of the red blood cell width;  usually RBC’s are a standard size (6-8mcm) but differences indicate certain disorders; higher RDW indicate greater variation in size;  normal reference range is 11-14%; RDW and MCV is used to help differentiate type of anemia of mixed causes from anemia of single cause – Example:  B12 deficiency produces macrocytic anemia w/ normal RDW; however iron deficiency anemia presents with varied size distribution of RBC’s with increased RDW — mixed iron and B12 deficiency, will normally be a mix of both large cells and small cells causing RDW to be elevated; Range: 11.6-16.0%
  • Hemoglobin (HGB) – the amount of hemoglobin in the blood; hemoglobin is the protein that binds oxygen to red blood cells in order to help oxygenate tissues throughout the body; low hemoglobin is considered an anemic state; Range: 12.0-15.0 g/dL (Andrea’s ideal MINIMUM of 12.0)
  • Hematocrit (HCT) or packed cell volume (PCV) – the fraction of whole blood that is just red blood cells; measured in a percentage; Range: 35.0-49.0% (Andrea’s ideal 38+)
  • Total white cells – all white cell types are given as percentage and given as an absolute number per liter; if CBC w/diff, then following:
    • Neutrophil granulocytes – may indicate bacterial infection; may also indicate acute viral infections; Range: 1.4-6.5 X10^9/L
    • Lymphocytes – higher with some viral infections; Range: 1.2-3.4 X10^9L
    • Monocytes - may be raised in bacterial infections; Range: 0.1-0.6 X10^9L
    • Eosinophil granulocytes – increased in parasitic infections, asthma, or allergic reactions; Range: 0.0-0.7 X10^9L
    • Basophil granulocytes – may be increased in bone marrow-related conditions; Range: 0.0-0.2 X10^9L
  • Platelets - numbers given as well as info about there size, range of sizes in the blood; platelets are small cell fragments that are rich in growth factors and are important to blood clotting action; too few lead too bleeding disorders, too many could lead to blood clots; Range: 150-450 X10^9L
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2 Responses to “Complete Blood Count”

  1. MacMadame says:

    What if some of your white cell counts are low?

  2. Andrea says:

    White counts are all immunology. I really didn’t go into immunology all that deeply because that’s REALLY medical stuff. But low can mean illness as well.

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