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Published on: September 5, 2016
Inflammation, anemia, and vitamin D levels associate with infant thrombocytosis risk
Sahaana S Rajagopalan1, Brian M Dulmovits1, Matthew Devine1
1Division of Neonatology, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Insights
Infant thrombocytosis, particularly in preterm infants, is linked to inflammation, anemia, and low vitamin D levels. Extreme thrombocytosis (EXT) in NICU infants did not lead to thrombotic complications.
Area of Science:
- Neonatal Medicine
- Pediatric Hematology
- Clinical Research
Background:
- Thrombocytosis, defined as elevated platelet counts (>500 × 10^3/μL), is common in infants, often stemming from infection, inflammation, or anemia.
- Extreme thrombocytosis (EXT, >1000 × 10^3/μL) can complicate diagnosis and management in hospitalized infants, sometimes necessitating invasive procedures or anticoagulation.
- Previous studies noted higher thrombocytosis rates in hospitalized infants, but often excluded extremely preterm infants who are at higher risk for thrombocytosis-promoting conditions.
Purpose of the Study:
- To determine the incidence and causes of thrombocytosis and EXT in infants admitted to tertiary neonatal intensive care units (NICUs).
- To identify factors associated with thrombocytosis risk in both preterm and full-term infants.
- To inform clinical decision-making regarding the evaluation and management of thrombocytosis in neonates.
Main Methods:
- A retrospective analysis was conducted on 20,818 infants hospitalized in two tertiary NICUs between 2011 and 2023.
- Data were compared with 10,323 patients from a quaternary NICU to assess relative incidence rates.
- Infant platelet counts, associated clinical factors (leukocytosis, anemia), and potential contributing elements (vitamin D, thyroid hormone, liver function) were examined.
Main Results:
- Thrombocytosis occurred in 3% of all infants (8% of preterm infants) in tertiary NICUs, significantly lower than the 20% incidence in the quaternary NICU.
- Extreme thrombocytosis (EXT) rates were also lower in tertiary units (0.08% vs. 0.5%).
- Thrombocytosis correlated with leukocytosis and anemia but not with thrombotic or bleeding events. Lower vitamin D levels were inversely associated with platelet counts in affected infants.
Conclusions:
- Infant thrombocytosis and EXT in NICU settings are associated with inflammation, anemia, and vitamin D deficiency.
- Unlike in adults, liver and thyroid immaturity did not appear to be significant drivers of thrombocytosis in this infant cohort.
- Importantly, no thrombotic complications were observed in infants with extreme thrombocytosis, suggesting a potentially different risk profile compared to other populations.
Background:
Thrombocytosis (>500 × 103 platelets/μL blood) occurs in infants due to infection, inflammation, and/or anemia. Thrombocytosis and extreme thrombocytosis (EXT, >1000 × 103 platelets/μL blood) can present diagnostic dilemmas, sometimes prompting invasive testing and anticoagulation therapy. We previously identified heightened thrombocytosis rates in hospitalized infants versus older children, but this population largely excluded extremely preterm infants at increased risk for infections and anemia-factors that promote thrombocytosis.
Objectives:
To define thrombocytosis and EXT rates, etiologies, and sequelae among infants hospitalized in tertiary neonatal intensive care units (NICUs) to assist clinical decision making and determine factors that associate with thrombocytosis risk in preterm and full-term patients.
Methods:
Retrospective analysis of thrombocytosis and EXT cases among 20,818 infants hospitalized in 2 tertiary NICUs from 2011 to 2023, compared to 10,323 patients hospitalized at a quaternary NICU.
Results:
Our results revealed thrombocytosis in 3% of all patients (8% of preterm infants). Both estimates were significantly lower than the incidence of thrombocytosis in quaternary NICU patients (20%). EXT was also reduced in our tertiary unit (0.08% vs 0.5% in quaternary NICU). Thrombocytosis was associated with leukocytosis and relative anemia, but not with thrombotic or bleeding complications. Thyroid hormone, liver-derived thrombopoietin, and vitamin D deficiency can drive thrombocytosis in adults. Vitamin D level, but not thyroid hormone or liver function, was inversely correlated with platelet count among infants with thrombocytosis.
Conclusions:
Inflammation, anemia, and vitamin D level correlate with infant thrombocytosis and EXT. Liver and thyroid immaturity do not appear to impact thrombocytosis risk. There were no thrombotic complications associated with EXT. These results provide important context for interpreting the origins and appropriate clinical responses to thrombocytosis in preterm infants.
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