Reference intervals for stool calprotectin in preterm neonates and their utility for the diagnosis of necrotizing enterocolitis.

OBJECTIVE: Calprotectin is an antimicrobial protein found in stool when released by granulocytes. We sought to create stool calprotectin reference ranges in preterm neonates and to evaluate whether levels exceeding the upper reference interval are diagnostic for necrotizing enterocolitis (NEC). STUDY DESIGN: Stool calprotectin was measured in premature neonates without gastrointestinal pathology to create reference intervals. For comparison, levels from infants undergoing "rule out NEC" evaluations were plotted on these reference intervals. RESULTS: Stool calprotectin reference intervals were created according to gestational age at birth and corrected gestational age. Levels during "rule out NEC" evaluations were more often above the upper reference interval with NEC vs. those without NEC. CONCLUSIONS: Stools from preterm neonates have a higher range of calprotectin than stools from healthy term neonates. In evaluating preterm neonates for NEC with stool calprotectin, a calprotectin upper reference interval that incorporates corrected gestational age best predicts the diagnosis of NEC.

ABO hemolytic disease of the fetus and newborn: thirteen years of data after implementing a universal bilirubin screening and management program.

OBJECTIVE: ABO hemolytic disease occurs among neonates with blood groups A or B delivered to group O women. Extreme neonatal hyperbilirubinemia due to ABO disease has been reported, but its frequency is not well known. We sought to determine the odds of developing severe ABO hemolytic disease in the 13 years since adopting universal bilirubin screening/management in the Intermountain Healthcare system. STUDY DESIGN: We conducted a retrospective analysis of neonates born between 2004 and 2016, defining "severe hemolytic disease" as; (1) total serum bilirubin (TSB) >25 mg/dL, or (2) hospital readmission for jaundice, or (3) bilirubin encephalopathy. Neonates born to group O (+) mothers were included and considered either; (1) Controls (not at risk for ABO disease because they were group O), (2) Study subjects (at risk for ABO disease because they were group A or B). RESULTS: Of 400,531 live births, 47% were to group O women; 86% of whom were group O (+). Overall, 42,529 (27%) neonates born to group O (+) women had their blood group determined; 29,729 (68%) were O, 10,682 (25%) A, and 3109 (7%) B. Peak TSBs during the first 10 days were higher in group A (11.0 ± 4.2 mg/dL) and B (11.5 ± 4.3) than group O neonates (10.3 ± 4.1). However the relative risks of a TSB ≥25 mg/dL, readmission for jaundice, or kernicterus, were the same in the control vs. study groups. CONCLUSIONS: In our health system, severe hemolytic disease in neonates born to group O (+) woman is not more likely in group A or B neonates than in controls (group O). We recognize that in other practices, particularly those who do not have a universal bilirubin screening/management program, ABO hemolytic disease severity might be different than in our system.

The immature platelet fraction: creating neonatal reference intervals and using these to categorize neonatal thrombocytopenias.

OBJECTIVE: The immature platelet fraction (IPF) is a laboratory measurement analogous to the reticulocyte count, but reflecting the thrombopoietic state. Similar to a reticulocyte count, it can be expressed as a percent (IPF%=percent of platelets that are immature) or as an absolute number per µl blood; the immature platelet count (IPC=IPF% × platelets per µl of blood). STUDY DESIGN: Using a retrospective analysis of de-identified data from non-thrombocytopenic neonates, we created reference intervals for IPF% and IPC. We then tested the value of these measurements for categorizing thrombocytopenic neonates. RESULTS: New charts display reference intervals for IPF% and IPC on the day of birth according to gestational age, and during the first 90 days after birth. Neonates with hyporegenerative varieties of thrombocytopenias (syndromes, small for gestational age, birth asphyxia) had lower IPF% and IPC than did neonates with consumptive thrombocytopenias (immune-mediated, infection, disseminated intravascular coagulation, necrotizing enterocolitis; both P<0.0001). CONCLUSION: The new reference interval charts can be used to recognize abnormal IPFs. The IPF parameters can help clarify the kinetic mechanism responsible for thrombocytopenias in neonates.

The iron status at birth of neonates with risk factors for developing iron deficiency: a pilot study.

OBJECTIVE: Small-for-gestational-age (SGA) neonates, infants of diabetic mothers (IDM) and very-low-birth weight premature neonates (VLBW) are reported to have increased risk for developing iron deficiency and possibly associated neurocognitive delays. STUDY DESIGN: We conducted a pilot study to assess iron status at birth in at-risk neonates by measuring iron parameters in umbilical cord blood from SGA, IDM, VLBW and comparison neonates. RESULTS: Six of the 50 infants studied had biochemical evidence of iron deficiency at birth. Laboratory findings consistent with iron deficiency were found in one SGA, one IDM, three VLBW, and one comparison infant. None of the infants had evidence of iron deficiency anemia. CONCLUSIONS: Evidence of biochemical iron deficiency at birth was found in 17% of screened neonates. Studies are needed to determine whether these infants are at risk for developing iron-limited erythropoiesis, iron deficiency anemia or iron-deficient neurocognitive delay.

Recombinant tissue plasminogen activator to restore catheter patency: efficacy and safety analysis from a multihospital NICU system.

OBJECTIVE: In 2001, the US Food and Drug Administration approved recombinant tissue plasminogen activator (alteplase, Cathflo Activase) to reestablish patency of central catheters occluded, presumably, by a fibrin clot. We conducted a multicenter quality improvement study to determine the value of this procedure in our Neonatal Intensive Care Unit (NICUs), including analyses of efficacy, safety and costs. STUDY DESIGN: We conducted a retrospective quality analysis of neonates in level III NICUs, who received alteplase for the purpose of reestablishing patency of occluded central catheters. RESULTS: Alteplase was administered to 169 neonates, each given one to four doses, totaling 205 episodes of administration. The most common type of catheter where alteplase was used was percutaneously inserted central catheter (PICC) lines (78% of uses), 8% were umbilical venous catheters (UVCs), 6% arterial lines, 5% chest tubes and 3% other catheters. Postnatal age at first dose ranged from 0 to 132 days (median, 12); dosed patients were 22 to 41 weeks gestation at birth (median, 31). Fifty-eight percentage of administrations restored catheter function. Success was more likely at younger postnatal age (10±2 days old in successful vs 14±1 days in unsuccessful treatments; P=0.023). Seventy-two percentage of the re-canalized catheters remained functional until they were no longer needed (2 to 30 days later). Nine percentage of episodes were treated with a second dose 1 to 17 days later for re-occlusion and 50% of those were successful. Bleeding consequences were identified in only one case, where three separate lines were treated (chest tube, PICC and UVC) within a 6-h period. Costs to the health system of doses, minus savings to the system by not needing to replace lines, averaged a net of $34 per dose. CONCLUSIONS: The apparent safety and favorable value analysis prompted us to develop a consistent approach to alteplase usage in the Intermountain Healthcare NICUs, using the data in this report to standardize the guidelines across our health system.

Elevated fecal calprotectin levels during necrotizing enterocolitis are associated with activated neutrophils extruding neutrophil extracellular traps.

OBJECTIVE: Neonates with necrotizing enterocolitis (NEC) have higher calprotectin levels in stool than do healthy neonates. However, it is not known whether high stool calprotectin at the onset of bowel symptoms identifies neonates who truly have NEC vs other bowel disorders. STUDY DESIGN: Neonates were eligible for this study when an x-ray was ordered to 'rule-out NEC'. Stool calprotectin was quantified at that time and in a follow-up stool. Each episode was later categorized as NEC or not NEC. The location of calprotectin in the bowel was determined by immunohistochemistry. RESULTS: Neonates with NEC had higher initial and follow-up stool calprotectin levels than did neonates without NEC. Calprotectin in bowel from neonates with NEC was within neutrophil extracellular traps (NETs). CONCLUSION: At the onset of signs concerning for NEC, fecal calprotectin is likely to be higher in neonates with NEC. Calprotectin in their stools is exported from neutrophils via NETs.

Comparing automated vs manual leukocyte differential counts for quantifying the 'left shift' in the blood of neonates.

OBJECTIVE: The neutrophil 'left shift' can be measured via the immature to total (I/T) neutrophil ratio or the absolute bands per µl using a manual differential count. It can also be measured from an automated differential count by the immature granulocyte percentage (IG%) or the absolute IG per µl. In neonates, it is unknown if the manual or automated differential count is superior. STUDY DESIGN: We directly compared complete blood counts (CBCs) with manual and automated differential counts from infants <90 days old, and documented whether or not each neonate was infected. We developed reference intervals for I/T ratio, bands per µl, IG% and IG per µl using values from non-infected neonates. RESULTS: The database had 10 714 CBCs. The upper reference interval for I/T ratio was 0.29 in the first 48 h and 0.31 thereafter; bands per µl was 3710 µl(-1) in the first 48 h and 1785 µl(-1) thereafter. IG% was 6.2% then 4.2%; IG per µl was 1460 µl(-1) then 613 µl(-1). Statistical performances of the four methods were equivalent for identifying infection. CONCLUSIONS: We developed reference intervals for four methods of quantifying a neonate's 'left shift'. The information from automated differentials is not inferior to that from manual differentials in identifying infections, but automated differentials have the advantages of a larger sample size, being less expensive, and faster performance times.