Background & Objectives
Anemia is a common morbidity in pediatric patients who require home parenteral nutrition (HPN). One factor that increases the risk for anemia in this patient population is frequent phlebotomy as part of routine monitoring. At Loma Linda University Children’s Hospital (LLUCH), the majority of pediatric patients on HPN have monthly labs drawn as part of the standard monitoring protocol. In June 2016, LLUCH began using micro-tubes for routine blood sampling. Traditional phlebotomy tubes require 15-20 mLof blood. Micro-tubes require less than 2mLfor the same tests. The purpose of this study is to understand the effects of phlebotomy blood volume minimization strategies in reducing anemia in our pediatric patients requiring HPN.

Methods
This study was IRB-approved and retrospective in design. Since June 2016, the HPN program at LLUCH began using micro tubes for routine laboratory monitoring. Standard clinical data (age, gender, weight) and laboratory data (CBC, ALT, bilirubin, albumin) were collected prior to June 2016 and after September 2016. The primary outcome of this study was to compare the change in hemoglobin concentrations before and after the use of micro-tubes. The secondary outcome was to estimate the prevalence of anemia for age before and after use of micro-tubes for phlebotomy. Statistical analyses were performed including standard descriptive analysis, t-tests, and bivariate analysis. P-value of <0.05 was considered statistically significant. The sensitivity and specificity of red cell mean corpuscle volume (MCV) and red cell distribution width (RDW) in detecting anemia for ages were also calculated.

Results
N = Thirty-eight subjects. Mean age = 6.1 years (SD +/- 4.2y).
Prevalence of anemia for age before micro-tube implementation = 22%
Prevalence of anemia for age after micro-tube implementation = 14%
Mean difference in the hemoglobin of before and after implementation = +0.62g/dL(CI=0.21 to 1.02; p=0.004)

Secondary bivariate analysis:
No correlation between anemia for age and the following factors: age, gender, weight, ALT, and albumin level.

Conclusions
Strategies such as micro-tubes to reduce the volume of routine blood draws in pediatric patients requiring chronic HPN may reduce the prevalence of anemia and improve hemoglobin levels. Age, weight, and liver enzyme levels were not found to be independent risk factors for the presence of anemia for age.