Blood Samples from Subject 1 through 7 years of age for Reference Interval Determinations for Clinical Laboratory Tests

1. Introduction: The hemostatic system during infancy and childhood differs from adults.  Reference ranges for plasma concentrations for the majority of known coagulation proteins during childhood were published (Andrew M, et al) in the late 1980’s and early 1990’s, and are still used to date.  Although these studies contributed significantly to the field, the current methods that are routinely used to determine coagulation protein concentrations are different. Current methods may yield different values due to differences in calibration and/or analytical specificity, mandating new reference ranges with the present standards of measurement.  In addition, small sample sizes were utilized in the original studies.  The determination of appropriate reference intervals is critical for accurate test interpretation.

   • Parental Permission Form

   Length of Study: Indefinite (1-2 years will probably be required)

   Number of Subjects: 480 for entire study

   Characteristics of Participants: Boys and girls between the ages of 1 and 7 years who are willing and able to provide a blood sample.

   Subject Groups Excluded: Those with any chronic medical condition requiring prescription medications(s).

   Location of Study: Primary Children's Medical Center, Salt Lake City, Utah

   Objectives: The purpose of this protocol is to collect blood samples from normal children between the ages of 1-6 years to determine reference intervals for the following list of laboratory tests:

   Analytes:

   • Citrate plasma(13)
   • Factor II
   • Factor VII
   • Factor VIII
   • Factor IX
   • Factor XI
   • Fibrinogen
   • Antithrombin
   • Protein C
   • Protein S
   • Von Willebrand factor antigen
   • Von Willebrand factor (ristocetin cofactor)
   • Partial Thromboplastin time
   • Prothrombin time