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Causes of high and low reticulocytes
Medical expert of the article
Last reviewed: 04.07.2025
Reference values (norm) for reticulocyte content are 0.2-1% of all erythrocytes circulating in the blood; 30-70×10 9 /l of reticulocytes circulate with the blood.
The amount of reticulocytes in the blood reflects the regenerative properties of the bone marrow. An increase in the content of reticulocytes is observed with increased regeneration of hematopoiesis, a decrease - with suppression of the regenerative function of the red bone marrow.
An increase in the number of reticulocytes is possible after blood loss, in hemolytic anemias, especially during a crisis (up to 20-30% or more), as well as during treatment with cyanocobalamin for vitamin B12 - deficiency anemia (reticulocyte crisis - an increase in the number of reticulocytes on the 5th-9th day of treatment). Reticulocyte crisis is also noted on the 3rd-5th day of treatment for iron deficiency anemia with parenteral iron preparations.
Modern hematological analyzers are able to determine 10 fractions of reticulocytes in the blood. The fraction of immature reticulocytes is the ratio of fractions 3 to 10 to the total number of reticulocytes and is normally 0.155-0.338 (when using Beckman Culter analyzers). When treating anemia with erythropoietin, the effectiveness of the therapy is indicated by an increase in the fraction of immature reticulocytes, which can be detected on the 7th day from the start of treatment.
Diseases and conditions associated with changes in the number of reticulocytes
Increased reticulocyte count |
Decreased reticulocyte count |
Hemolytic syndromes Acute oxygen deficiency On the 3rd-5th day after blood loss (reticulocyte crisis) Vitamin B 12 - deficiency anemia on the 5th-9th day after the start of treatment (reticulocyte crisis) On the 3rd-5th day of treatment with iron preparations for iron deficiency anemia |
Untreated vitamin B12 deficiency anemia Metastases of neoplasms to bones |