title: The immature platelet fraction: creating neonatal reference intervals and using these to categorize neonatal thrombocytopenias.
abstract: The immature platelet fraction (IPF) is a laboratory measurement analogous to the reticulocyte count, but reflecting the thrombopoietic state. Similar to a reticulocyte count, it can be expressed as a percent (IPF%=percent of platelets that are immature) or as an absolute number per μl blood; the immature platelet count (IPC=IPF% × platelets per μl of blood).
  
  
  
  Using a retrospective analysis of de-identified data from non-thrombocytopenic neonates, we created reference intervals for IPF% and IPC. We then tested the value of these measurements for categorizing thrombocytopenic neonates.
  
  
  
  New charts display reference intervals for IPF% and IPC on the day of birth according to gestational age, and during the first 90 days after birth. Neonates with hyporegenerative varieties of thrombocytopenias (syndromes, small for gestational age, birth asphyxia) had lower IPF% and IPC than did neonates with consumptive thrombocytopenias (immune-mediated, infection, disseminated intravascular coagulation, necrotizing enterocolitis; both P<0.0001).
  
  
  
  The new reference interval charts can be used to recognize abnormal IPFs. The IPF parameters can help clarify the kinetic mechanism responsible for thrombocytopenias in neonates.
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors.forename: B C
authors.initials: BC
authors.lastname: MacQueen
authors.affiliation: Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA.|Women and Newborn's Clinical Program, Intermountain Healthcare, Salt Lake City, UT, USA.|Department of Pediatrics, Division of Hematology/Oncology, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Christensen
authors.affiliation: Women and Newborn's Clinical Program, Intermountain Healthcare, Salt Lake City, UT, USA.|Institute for Healthcare Delivery Research, Salt Lake City, UT, USA.
authors.forename: E
authors.initials: E
authors.lastname: Henry
authors.affiliation: Women and Newborn's Clinical Program, Intermountain Healthcare, Salt Lake City, UT, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Romrell
authors.affiliation: Department of Pathology, University of Utah School of Medicine, Primary Children's Hospital, Salt Lake City, UT, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Pysher
authors.affiliation: Department of Pathology, Intermountain Medical Center, Murray,UT, USA.|Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Bennett
authors.affiliation: Division of Newborn Medicine, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
authors.forename: M C
authors.initials: MC
authors.lastname: Sola-Visner
mesh_terms: D001792:Blood Platelets; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010976:Platelet Count / Q000295:instrumentation / Q000379:methods; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D054098:Thrombocytopenia, Neonatal Alloimmune / Q000097:blood / Q000175:diagnosis*