Rare diseases · Sign or symptom
Reticulocytosis
Increased immature red blood cells
HP:0001923
What it means
An elevation in the number of reticulocytes (immature erythrocytes) in the peripheral blood circulation.
Rare diseases that can present with this26
Very common80–99%
5Common30–79%
13- Abetalipoproteinemia
- Alpha-thalassemia
- Autoimmune hemolytic anemia, warm type
- Dehydrated hereditary stomatocytosis
- Glycogen storage disease due to phosphoglycerate kinase 1 deficiency
- Hemolytic anemia due to glucophosphate isomerase deficiency
- Hereditary spherocytosis
- Imerslund-Gräsbeck syndrome
- Immune-mediated thrombotic thrombocytopenic purpura
- Marburg hemorrhagic fever
- Paroxysmal nocturnal hemoglobinuria
- Sickle cell anemia
- Southeast Asian ovalocytosis
Sometimes5–29%
7The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Increased number of immature red blood cells · Increased reticulocyte count · Increased reticulocytes
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.