Flashcards in Pediatric CBC Deck (24)
what blood components are included in the CBC?
RBCs, WBCs, platelets
what is the accepted range of WBCs for newborns?
9000 - 30,000
neutrophils account for what % of WBCs at birth?
when is the number of absolute bands highest?
first 2 days of life
how do you calculate the I:T ratio?
1. sum of immature forms in numerator
2. total neutrophil forms in denominator
what I:T ratio signifies a high suspicion for sepsis?
greater than 0.20
how do Hb and Hct levels at birth compare to kids and adults?
what is the normal ratio of Hct to Hb?
what is polycythemia? what is the diagnostic value associated with it?
1. pathologic increase in RBC mass
2. venous Hct greater than 65% in neonatal period
how does capillary Hct compare to venous?
runs slightly higher
why do capillary Hct samples run higher than venous?
manual pushing from heel stick results in an increased proportion of cells to be obtained compared to fluid volume
what are the clinical outcomes of venous polycythemia greater than 65%?
what is the treatment for symptomatic and asyomptomatic polylcythemia?
1. symptomatic - exchange transfusion
2. asymptomatic - hydrate and monitor
how is polycythemia defined after the neonatal period?
Hb and Hct that is two standard deviations above the mean
what is the RBC lifespan in the newborn?
what is the cause of physiologic anemia of infancy?
fall in Hb around 2 months of age due to
1. decreased RBC lifespan
2. decreased erythropoiesis
how do you calculate the lower limit of MCV in children under 10 years of age?
70 fL plus age in years
how do you calculate the upper limit of MCV (after 6 months of age)?
84 fL plus (0.6 x age in years)
what is the normal range for platelets throughout life?
150,000 - 450,000
what are the three causes of thrombocytopenia in the newborn?
what are the mechanism for sepsis induced thrombocytopenia in the newborn?
1. Transient hypoproliferative state in bone marrow
2. Platelet aggregation from bacterial products
what is the mechanism for ITP induced thrombocytopenia in the newborn?
autoimmune - mother has Abs that react with platelets - also react with baby's platelets
what is the mechanism for alloimmune thrombocytopenia?
1. transfer of Abs across the placenta
2. coated platelets are destroyed