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Calculation of Reticulocyte Production Index Correction #1 for anemia: This correction produces the corrected reticulocyte count In a person whose reticulocyte count is 9%, hemoglobin 7.5 g/dL, hematocrit 23%, the absolute reticulocyte count = 9 x (7.5/15) [or x (23/45)]= 4.5% Correction #2 for longer life of prematurely released reticulocytes in the blood: This correction produces the reticulocyte production index In a person whose reticulocyte count is 9%, hemoglobin 7.5 gm/dL, hematocrit 23%, the reticulocyte production index Figure 58-13 Correction of the reticulocyte count. In order to use the reticulocyte count as an indicator of effective red cell production, the reticulocyte number must be corrected. | Chapter 058. Anemia and Polycythemia Part 7 Table 58-4 Calculation of Reticulocyte Production Index Correction 1 for anemia This correction produces the corrected reticulocyte count In a person whose reticulocyte count is 9 hemoglobin 7.5 g dL hematocrit 23 the absolute reticulocyte count 9 x 7.5 15 or x 23 45 4.5 Correction 2 for longer life of prematurely released reticulocytes in the blood This correction produces the reticulocyte production index In a person whose reticulocyte count is 9 hemoglobin 7.5 gm dL hematocrit 23 the reticulocyte production index _ qx 7.5 15 h emoglob in correction 2 mat u rat ion time correction 2.25 Figure 58-13 Correction of the reticulocyte count. In order to use the reticulocyte count as an indicator of effective red cell production the reticulocyte number must be corrected based on the level of anemia and the circulating life span of the reticulocytes. Erythroid cells take 4.5 days to mature. At normal hematocrit levels they are released to the circulation with 1 day left as reticulocytes. However with different levels of anemia erythroid cells are released from the marrow prematurely. Most patients come to clinical attention with hematocrits in the mid-20s and thus a correction factor of 2 is commonly used because the observed reticulocytes will live for 2 days in the circulation before losing their RNA. Premature release of reticulocytes is normally due to increased EPO stimulation. However if the integrity of the bone marrow release process is lost through tumor infiltration fibrosis or other disorders the appearance of nucleated red cells or polychromatophilic macrocytes should still invoke the second reticulocyte correction. The shift correction should always be applied to a patient with anemia and a very high reticulocyte count to provide a true index of effective red cell production. Patients with severe chronic hemolytic anemia may increase red cell production as much as six- to sevenfold. This measure alone therefore .
