Reticulocyte Count

Looking at Labs

Reticulocyte count

Background Normal reference values • RBC enzyme deficits A reticulocyte—a young, imma- Adults: 0.5% to 1.5% of total • after hemorrhage (3 to 4 days) ture, nonnucleated red blood erythrocytes (percentage may be • after treatment of anemias. cell (RBC)—contains reticular slightly higher in women) An increased reticulocyte material (RNA) that stains gray- Absolute count: 25,000 to count may be used as an index blue. Reticulum is present in 75,000/mcL1 of treatment effectiveness. After newly released blood cells for Reticulocyte production index adequate doses of iron in iron- 1 to 2 days before the cells (RPI) = [% reticulocyte count x deficiency anemia, the rise in reach their fully mature state. patient hematocrit (Hct)]/ reticulocytes may exceed 20%. Normally, a small number of 45(normal Hct)2 There is a proportional increase these cells are found in circu- when pernicious anemia is treat- lating blood. For the reticulo- Clinical implications ed by transfusion or vitamin B12 cyte count to be meaningful, An increased reticulocyte count therapy. it must be viewed in relation (reticulocytosis) means that A decreased reticulocyte to the total number of eryth- increased RBC production is count (reticulocytopenia) means rocytes (absolute reticulocyte occurring as the bone marrow that the bone marrow is not count = % reticulocytes × replaces cells lost or prematurely producing enough erythrocytes. erythrocyte count). destroyed. Identification of retic- This occurs in: • untreated iron-deficiency anemia Identification of reticulocytosis may lead to • aplastic anemia (a persistent the recognition of an otherwise occult disease, deficiency of reticulocytes sug- such as hidden chronic hemorrhage or gests a poor prognosis) unrecognized hemolysis. • untreated pernicious anemia • anemia of chronic disease • radiation therapy The reticulocyte count is ulocytosis may lead to the rec- • endocrine disorders used to differentiate anemias ognition of an otherwise occult • tumor in bone marrow (bone caused by bone marrow failure disease, such as hidden chronic marrow failure) from those caused by acute or hemorrhage or unrecognized • myelodysplastic syndromes chronic blood loss or hemolysis hemolysis (for example, sickle • alcoholism. ■ (destruction of RBCs); assess cell anemia, or thalassemia). Source: Fischbach FT, Fischbach MA. A Manual of the effectiveness of treatment in Reticulocytosis is observed in the Laboratory and Diagnostic Tests. 10th ed. Philadelphia, pernicious anemia and folate and following: PA: Wolters Kluwer; 2018. iron deficiency anemias; assess • hemolytic anemia REFERENCES: the recovery of bone marrow • immune hemolytic anemia 1. Leung LLK. Approach to the adult with ane- function in aplastic anemia; and • primary RBC membrane prob- mia. UpToDate. 2020. www.uptodate.com. 2. Rai D, Wilson AM, Moosavi L. Histology, Re- determine the effects of radio- lems ticulocytes. StatPearls. 2019. active substances on exposed • hemoglobinopathic and sickle workers. cell disease DOI-10.1097/01.CCN.0000694112.81243.1d

38 l Nursing2020CriticalCare l Volume 15, Number 5 www.nursingcriticalcare.com