From the Guidelines
A normal reticulocyte count indicates that the bone marrow is producing red blood cells at a normal rate, while an abnormal count can suggest various underlying conditions such as anemia, blood loss, or bone marrow dysfunction.
Interpretation of Reticulocyte Count
- A normal reticulocyte index (RI) ranges between 1.0 and 2.0 1, which suggests that the bone marrow is producing red blood cells at a normal rate.
- A low RI indicates decreased RBC production, which can be caused by iron deficiency, vitamin B12/folate deficiency, aplastic anemia, or bone marrow dysfunction 1.
- A high RI indicates normal or increased RBC production, which can be caused by blood loss or hemolysis in patients with anemia 1.
Immature Platelet Ratio (IPR)
There is no direct information provided about the Immature Platelet Ratio (IPR) in the given evidence. However, it is known that the IPR is a measure of the ratio of immature platelets to total platelets, which can be used to evaluate platelet production and turnover.
Clinical Implications
- A comprehensive evaluation of anemia should include both morphologic and kinetic approaches, including reticulocyte count and other tests such as iron studies and vitamin B12/folate levels 1, 2.
- Iron deficiency is a common cause of anemia, and evaluation of iron sufficiency is an important part of the initial evaluation of anemia in patients with chronic kidney disease (CKD) 2, 3.
- The presence of iron deficiency requires a search for the cause, which is usually blood loss, and a stool guaiac test for occult blood is recommended to test for gastrointestinal bleeding in patients with iron deficiency 3.
From the Research
Reticulocyte Count Interpretation
- A normal reticulocyte count is used to estimate red cell life span and red cell production in clinical practice 4.
- The reticulocyte count can be used to evaluate the erythropoietic activity in anemia, with an increased reticulocyte count indicating an adequate erythroid response to anemia 5.
- The reticulocyte production index (RPI) is a calculated parameter that supports the interpretation of reticulocyte count results, taking into account the patient's hematocrit and reticulocyte count 4.
Immature Platelet Ratio (IPR) Interpretation
- There is no direct information available on the Immature Platelet Ratio (IPR) in the provided studies.
- However, the immature reticulocyte fraction (IRF) is a related parameter that has been studied, which is defined as the sum of the fraction of high-fluorescence intensity regions plus the fraction of middle-fluorescence intensity regions 5.
- An increased IRF (IRF > or = 0.23) generally indicates an adequate erythroid response to anemia, while a decreased IRF (IRF < 0.23) may reflect a nonresponsive or underresponsive bone marrow 5.
Reference Ranges for Reticulocyte Count and Derived Parameters
- Reference ranges for reticulocyte count and derived parameters, such as IRF, vary depending on the laboratory and instrumentation used 6, 7.
- Studies have established reference intervals for reticulocyte profile parameters in healthy adults using different statistical approaches 7.
- The reference ranges for reticulocyte count and derived parameters in children have also been established, with values varying by age 8, 6.