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Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
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Normal aPTT in children with mild factor XI deficiency.

John Puetz1, Christopher Hugge1, Karen Moser2

  • 1Division of Pediatric Hematology/Oncology, Department of Pediatrics, Saint Louis University School of Medicine, St. Louis, Missouri.

Pediatric Blood & Cancer
|December 13, 2017
PubMed
Summary

Children with factor XI deficiency may present with a normal activated partial thromboplastin time (aPTT). This finding suggests that a normal aPTT does not rule out factor XI deficiency in pediatric patients.

Keywords:
aPTTfactor XIfactor XI deficiencyhemophilia C

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Area of Science:

  • Pediatric Hematology
  • Hemostasis and Thrombosis
  • Coagulation Disorders

Background:

  • The activated partial thromboplastin time (aPTT) is a key laboratory test in the diagnostic workup of bleeding disorders.
  • Previous studies suggest that factor XI deficiency may not always prolong the aPTT, but data in pediatric populations are limited.
  • Understanding the relationship between factor XI activity and aPTT in children is crucial for accurate diagnosis.

Purpose of the Study:

  • To investigate the prevalence of a normal aPTT in children diagnosed with factor XI deficiency.
  • To determine if a normal aPTT can exclude the need for factor XI activity testing in pediatric patients with bleeding symptoms.

Main Methods:

  • Retrospective review of an institutional database.
  • Identification of pediatric patients with a confirmed diagnosis of factor XI deficiency.
  • Analysis of activated partial thromboplastin time (aPTT) results in this cohort.

Main Results:

  • Seven children with factor XI deficiency were identified.
  • Four out of seven children (approximately 57%) with factor XI deficiency exhibited a normal aPTT.
  • This indicates that a normal aPTT is observed in a significant proportion of pediatric cases.

Conclusions:

  • A normal activated partial thromboplastin time (aPTT) does not reliably exclude factor XI deficiency in children.
  • Clinicians should consider factor XI activity testing in pediatric patients with unexplained bleeding, even with a normal aPTT.
  • These findings highlight the importance of considering factor XI deficiency in the differential diagnosis of bleeding disorders in children.