Thipwimol Tim-Aroon1, Heidi M Harmon2, Mary L Nock2, Sreekanth K Viswanathan2, Shawn E McCandless3. 1. Center for Human Genetics, University Hospitals Case Medical Center, Cleveland, OH; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH. 2. Division of Neonatology, Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH. 3. Center for Human Genetics, University Hospitals Case Medical Center, Cleveland, OH; Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH. Electronic address: Shawn.McCandless@uhhospitals.org.
Abstract
OBJECTIVE: To evaluate effects of holding parenteral nutrition (PN) for 3 hours prior to newborn screening (NBS) on false-positive NBS rate for amino acids (AAs) in very low birth weight (VLBW) infants (birth weight <1500 g). STUDY DESIGN: We analyzed data from 12 567 consecutive births in 1 hospital between May 2010 and June 2013. VLBW infants were stratified into 3 groups: (1) infants without PN before NBS (no-PN group); (2) infants with early PN running at the time of NBS (early-PN group); and (3) infants with early-PN that were temporarily replaced by dextrose-containing intravenous fluid 3 hours prior to NBS (stop-PN group). We compared the false-positive rate for AA and cost effectiveness between the groups. RESULTS: The false-positive rate for AA among 413 VLBW infants was significantly higher than infants with birth weight >1500 g (7.62% vs 0.05%; P < .001). There were no false-positive results for AA in the no-PN group. The false-positive rate for AA in the stop-PN group (2/65) was significantly lower than the early-PN group (29/245) (3.1% vs 11.8%; P = .037). The stop-PN group was more cost effective than early-PN group, saving $17.27 per infant screened ($5.53 vs $22.80) or $192.54 for each false-positive result for AA averted. Further reductions in inconclusive samples were also noted. CONCLUSIONS: VLBW and early-PN are significant factors for false-positive results for AA. Holding PN containing AAs for 3 hours before NBS collection is a practical and cost-effective method to significantly reduce the false-positive rate for AA in VLBW infants.
OBJECTIVE: To evaluate effects of holding parenteral nutrition (PN) for 3 hours prior to newborn screening (NBS) on false-positive NBS rate for amino acids (AAs) in very low birth weight (VLBW) infants (birth weight <1500 g). STUDY DESIGN: We analyzed data from 12 567 consecutive births in 1 hospital between May 2010 and June 2013. VLBW infants were stratified into 3 groups: (1) infants without PN before NBS (no-PN group); (2) infants with early PN running at the time of NBS (early-PN group); and (3) infants with early-PN that were temporarily replaced by dextrose-containing intravenous fluid 3 hours prior to NBS (stop-PN group). We compared the false-positive rate for AA and cost effectiveness between the groups. RESULTS: The false-positive rate for AA among 413 VLBW infants was significantly higher than infants with birth weight >1500 g (7.62% vs 0.05%; P < .001). There were no false-positive results for AA in the no-PN group. The false-positive rate for AA in the stop-PN group (2/65) was significantly lower than the early-PN group (29/245) (3.1% vs 11.8%; P = .037). The stop-PN group was more cost effective than early-PN group, saving $17.27 per infant screened ($5.53 vs $22.80) or $192.54 for each false-positive result for AA averted. Further reductions in inconclusive samples were also noted. CONCLUSIONS: VLBW and early-PN are significant factors for false-positive results for AA. Holding PN containing AAs for 3 hours before NBS collection is a practical and cost-effective method to significantly reduce the false-positive rate for AA in VLBW infants.