This version was machine-translated from German and has not been medically reviewed. The authoritative version is the German version.
Reticulocyte production index (RPI)
Corrected reticulocyte count divided by the hematocrit-dependent maturation time – < 2 hypoproliferative, > 3 adequate response
Calculation aid for healthcare professionals: the calculator reproduces what the sources cited assign to the inputs. Clinical assessment and every treatment decision remain with the treating physician. Inputs and results are not stored.
Frequently asked questions
Reticulocyte production index (RPI): What does this calculator compute?
Calculates the reticulocyte production index from reticulocyte fraction, hematocrit and normal hematocrit with the maturation time according to Hillman & Finch (1.0 / 1.5 / 2.0 / 2.5 days at hematocrit 36–45 / 26–35 / 16–25 / ≤ 15 %); in anemia, RPI < 2 suggests an inadequate and > 3 an adequate bone marrow response.
Reticulocyte production index (RPI): Which sources is this calculator based on?
Doig K, Zhang B: A Methodical Approach to Interpreting the Red Blood Cell Parameters of the Complete Blood Count (Clin Lab Sci 30:173–185) (2017); Gaur M, Sehgal T: Reticulocyte count: a simple test but tricky interpretation! (Pan Afr Med J 40:3) (2021)