The desired use of the HPH Jr. is optimal due to the low priming volume; however, the lower rate of volume removal necessitates utilization of a larger hemofilter. Larger hemofilters carry a higher prime volume, which is impactful in the pediatric setting. Pediatric cardiac surgery patients under 18 kilograms requiring cardiopulmonary bypass were randomly assigned to one of two study groups. Group 1 (coated) contained an HPH Jr. hemofilter that was primed with the addition of 25% albumin and heparin. Group 2 (non-coated) contained an HPH Jr. hemofilter that was primed with only Normosol-R®. After cardioplegia delivery, zero balance ultrafiltration (ZBUF) was initiated and maintained for thirty consecutive minutes. The flow through the hemofilter was standardized at 70 ml/min and the vacuum applied to the effluent line was set at -150 mmHg. Effluent fluid removal was measured at the termination of thirty minutes and compared between the groups. Group comparisons between the coated vs non-coated hemofilter groups were assessed using two-sample t-tests or the Mann-Whitney U test, when appropriate. Forty-two patients were included in the analysis. There were 22 patients who had the non-coated hemofilter and 20 patients with a coated hemofilter. The differences between the two groups are illustrated in Table 1. There was a statistically significant higher ultrafiltration volume with the coated hemofilter group (p=0.008) (Figure 1). These results illustrate the improved efficiency of the HPH Jr. with the addition of 25% albumin and heparin during the priming process.