Reticulocyte count Flashcards
What is the reticulocyte count an indicator of?
Indicator of the ability of the bone marrow to respond to anemia and make RBCs
What is the reticulocyte count used for and what are the normal ranges?
- *Used to classify and monitor therapy of anemias**
- *Normal range = 0.5-2.0%** of total number of RBCs. Normally there are a small number of reticulocytes in the bloodstream
What is a reticulocyte?
Reticulocyte is an immature RBC that still has some microsomal and ribosomal material left in the cytoplasm. It may take a few days for that material to be cleared from the cell.
What does an increased reticulocyte count indicate?
Increased counts indicate the marrow is releasing an increased number of RBCs into the bloodstream, usually in response to anemia.
An elevated count with a normal Hgb and Hct indicates increased RBC production compensating for an ongoing loss of RBCs (hemolysis or hemorrhage).
What does a normal or low reticulocyte count in an anemic patient indicate?
A normal or low count in a patient with anemia indicates the marrow response to the anemia by way of RBC production is inadequate and may be contributing to or be the cause of the anemia (iron deficiency, B12 deficiency, depletion of iron stores, aplastic anemia)
How can anemia affect the reticulocyte count?
Reticulocyte count is a percentage of the total number of RBCs, so a normal to low number can appear high in anemia because the total number of mature RBCs is low.
What is the reticulocyte index?
To determine if the count is an appropriate bone marrow response in patients with anemia and decreased Hct, the reticulocyte index is calculated:
Reticulocyte index = Reticulocyte count(%) x (Patient Hct/Normal Hct)
In a good bone marrow response, what should the reiculocyte index value be?
A good marrow response to the anemia should have an index of 1.0. If it is < 1.0, even if the reticulocyte count is elevated, the bone marrow response is inadequate in its ability to compensate (iron deficiency, B12 deficiency, marrow failure).
What should be given if a patient has a low reticulocyte index?
If iron or vitamin supplement is given, the reticulocyte count will rise to the point the index is equal to or greater than 1.0
Interfering factors of reticulocyte count?
- *Pregnancy** may cause an increased count
- *Howell-Jolly bodies** are blue stippling material in the RBC seen in severe anemia or hemolytic anemia. These RBCs look like reticulocytes and can fool the automated counters
What can cause increased reticulocyte count?
Hemolytic anemia (immune hemolytic anemia, hemoglobinopathies, hypersplenism, trauma from prosthetic heart valve) – RBC survival is decreased and the cells are destroyed at a faster rate than normal, which stimulates the marrow to produce large number of RBCs, some of which are immature.
Hemorrhage (3-4 days later) – marrow responds to blood loss by producing large number of RBCs.
Hemolytic disease of the newborn – RBCs are destroyed, reducing their survival
Treatment for iron, vitamin B12, or folate deficiency – after treatment, the marrow responds by increasing production of RBCs
What causes a decreased reticulocyte count?
Pernicious anemia and folic acid deficiency, iron deficiency anemia – suppress production of RBCs
- *Aplastic anemia, Radiation therapy, Malignancy, Marrow failure, Adrenocortical hypofunction, Anterior pituitary hypofunction** – marrow fails to produce RBCs and reticulocytes
- *Chronic diseases** – marrow production of RBCs and reticulocytes is decreased.
