Erythropoiesis, Reticulocytes, Hematocrit, and ESR Review

Comprehensive flashcards covering the dynamic process of erythropoiesis, reticulocyte analysis, hematocrit determination methods, and the principles and factors affecting Erythrocyte Sedimentation Rate (ESR).

Erythropoiesis

The dynamic process by which mature erythrocytes are formed.

Erythropoietin (EPO)

The protein which has the command in the production of RBCs.

Effective Erythropoiesis

Refers to the number of functional and viable erythrocytes available for physiological needs with respect to the total number of erythrocytes produced, where $80-90\%$ are released into circulation and only $10-15\%$ are destroyed.

Total Erythropoiesis

A record of the number of erythrocytes produced with no indication as to whether the cells function properly or are able to live up to $120\,days$.

Ineffective Erythropoiesis

A condition where the bone marrow produces enough quantity of cells, but a reduced number are released into circulation because approximately $80-90\%$ are destroyed.

Hyperplasia

A state where the bone marrow is producing exceedingly higher or greater than the normal number of RBCs produced.

Hypoplasia

A state where the bone marrow is not producing enough RBCs, leading to a lesser number of RBCs being released and destroyed.

Reticulocyte

A young non-nucleated cell of the erythrocytic series representing the last immature red blood cell stage, characterized by blue stained granulofilamentous material (residual RNA) when using supravital stains.

Supravital Stain

A type of stain used for reticulocyte counting, such as new methylene blue, which stains the residual RNA as a blue-black dotting or network.

Shift Reticulocytes

Reticulocytes released from the bone marrow to the peripheral blood earlier than usual to compensate for anemia; they take $2$ to $3\,days$ to lose their reticula instead of the normal $1\,day$.

Reticulocyte Production Index (RPI)

A mathematical adjustment used to evaluate erythropoiesis; an adequate response is indicated by an RPI greater than $3$, while an inadequate response is less than $2$.

Hematocrit (HCT)

Also called packed cell volume (PCV), it is the volume of packed red blood cells that occupies a given volume of whole blood, reported as a percentage or in $L/L$.

Rule of Three

A habit for analysts to check accuracy where the value of the hematocrit should be three times the value of the hemoglobin plus or minus $3\%$: $HGB \times 3 = HCT \pm 3\%$, and $RBC \times 3 = HGB$.

Buffy Coat

A layer composed of platelets (upper thinner yellowish white creamy layer) and WBCs (lower thicker reddish gray layer) that should be excluded from the hematocrit reading.

Erythrocyte Sedimentation Rate (ESR)

The distance in millimeters that red blood cells fall in $1\,hour$ when anticoagulated blood is allowed to stand undisturbed at room temperature.

Rouleaux Formation

The initial period of ESR occurring in the first few minutes during which red blood cells form stacks.

Wintrobe Tube

A tube used for macrohematocrit and ESR measuring $11.5\,cm$ in length with a $3\,mm$ bore; the left side is marked $0-10$ for ESR and the right side $10-0$ for hematocrit.

Westergren Tube

A tube used for ESR with a length of $300\,mm$ and a bore of $2.5\,mm$; it typically requires $1.0\,ml$ of blood.

Ves-Matic System

A bench-top analyzer designed to determine ESR using an optoelectronic sensor; it accelerates sedimentation by positioning tubes at an $18$-degree angle and provides results in $20\,minutes$.

$59Fe$ (Iron 59)

A radioactive isotope of iron injected intravenously to measure red cell iron turnover and its incorporation into RBCs for hemoglobin synthesis.

$51Cr$ (Chromium 51)

A radioactive isotope used to tag RBCs to determine their lifespan; the normal half-life disappearance from circulation is $25-30\,days$.

Fecal Urobilinogen

A byproduct measured in feces used to indicate the degree of RBC destruction; an excess indicates more RBCs are being destroyed.

Pulmonary CO

Carbon monoxide, which is one of the byproducts of hemoglobin breakdown used to determine total erythropoiesis.