Hematology CBC and RBC Indices

Vocabulary flashcards covering complete blood count parameters, RBC indices formulas, reference ranges, and morphological definitions.

EDTA Tube

The collection tube containing anticoagulant used for standard complete blood count (CBC) whole blood specimens without centrifugation.

Rule of Three

A mathematical check in hematology where $\text{RBC} \times 3 = \text{Hemoglobin}$ and $\text{Hemoglobin} \times 3 = \text{Hematocrit}$, used to evaluate sample integrity and specimen printouts.

Normocytic Normochromic Anemia

A classification of anemia where red blood cells are normal in size (MCV between $80$ and $100\,\text{fL}$) and contain normal hemoglobin concentration.

Microcytic Red Blood Cells

Red blood cells that are smaller than normal with an MCV of less than $80\,\text{fL}$ and typically display a wide central pallor.

Macrocytic Red Blood Cells

Red blood cells that are larger than normal with an MCV of greater than $100\,\text{fL}$.

MCV (Mean Cell Volume)

A CBC parameter indicating average red blood cell size or volume, calculated as $\frac{\text{Hematocrit}}{\text{RBC}} \times 10$ and measured in femtoliters ($\text{fL}$).

MCH (Mean Corpuscular Hemoglobin)

A CBC parameter measuring the average weight of hemoglobin inside one red blood cell, expressed in picograms ($\text{pg}$) with a normal reference range of $27$ to $31\,\text{pg}$.

MCHC (Mean Corpuscular Hemoglobin Concentration)

A CBC parameter measuring the average percentage of hemoglobin inside a red blood cell, expressed as a percentage ($32\%$ to $36\%$) or in $\text{g/dL}$.

Central Pallor

The clear central area of a red blood cell where hemoglobin is absent, normally occupying approximately one-third of the cell.

Spherocytes

Spherical red blood cells lacking a central pallor that have elevated MCHC, are rigid, and cannot easily deform to travel through narrow blood vessels.

RDW (Red Blood Cell Distribution Width)

A calculated CBC parameter measuring the degree of variation in red blood cell size (anisocytosis) and shape (poikilocytosis), with a normal reference range of $11.5\%$ to $14.5\%$.

Anisocytosis

A medical term defined as abnormal variation in red blood cell size.

Poikilocytosis

A medical term defined as abnormal variation in red blood cell shape.

Critical Value

A laboratory result significantly outside normal reference ranges that indicates a potential life-threatening situation requiring rapid clinical verification and physician notification.

Anemia (Laboratory Definition)

The clinical condition defined specifically in the laboratory by decreased red blood cell count (RBC), low hemoglobin, and low hematocrit.

Packed Cell Volume (PCV)

An alternative clinical term for hematocrit.