A Reappraisal of Neonatal Blood Chemistry Reference Ranges Using the Nova M Electrodes

Abstract

The objective of this study is to establish new reference ranges for whole blood electrolytes, gases, and selected chemistries in normal healthy newborn infants obtained from cord blood and at 2-4 hours of life based on modern analytic techniques. Healthy appropriate-for-gestational age (AGA), term infants were studied. Whole venous cord blood and blood drawn at 2-4 hours of life were analyzed for gases, sodium, potassium, chloride, ionized calcium, ionized magnesium, hemoglobin, and hematocrit. Concentrations for blood glucose and blood urea nitrogen were close to older published concentrations. Na(+), K(+), and Cl(-) were significantly different and had much narrower normal margins. New norms are included for blood gases, lactate, iCa, and iMg. We offer a range of values for often-measured blood chemistries in term, healthy infants, using modern laboratory methods. These values could serve as more up-to-date references compared with older values found in major textbooks of Neonatology.

Reference intervals and age‐related changes for venous biochemical, hematological, electrolytic, and blood gas variables using a point of care analyzer in 68 puppies

“…This is in disagreement with a previous study that showed a lower potassium at ages 2–4 weeks with a peak at 6–8 weeks with a gradual drop off to adult levels . Concentrations in humans do not reflect these referenced trends; they show an initially higher concentration of potassium that lessens with age . This initial relative hyperkalemia may be the result of a shift of potassium from intracellular to extracellular space but may only occur in the premature infant and the mechanism is unknown .…”

“…The point‐of‐care analyzer used in the present study has been shown to provide acceptable performance when compared to standard laboratory methods . A second study evaluated the accuracy of the analyzer using human neonatal samples and showed good correlation with published reference intervals . To date, there are no veterinary studies validating neonatal POC results to standard laboratory analyzer results; the volume of sample needed for this type of study could be potentially harmful.…”

A tale of two bridges: Effect of the bloodless bridge on renal function and blood pressure in neonates managed with venoarterial extracorporeal membrane oxygenation

“…For both groups, mean blood urea nitrogen values were significantly higher than the normal reference range for term newborns (14). Creatinine was initially elevated, but decreased over time and was within normal range (16) on days 2 and 3 of ECMO.…”

“…The differences in blood pressures were further evaluated by controlling for birth weight, gestational age, gender, race, and use of antihypertensive therapy in a multiple regression model. Based upon normative data for blood pressure (13) and renal function (14) in newborns, we calculated that a sample size of 50 patients in each group would be able to detect a moderate effect size (8% to 10% difference in mean blood pressure, 15% difference in blood urea nitrogen) between groups (␣ Ͻ 0.05, ␦ ϭ 1, and ␤ ϭ 20%). Statistical analysis was performed using SPSS 12.0 software (15).…”

Reducing blood transfusion requirements in preterm infants by a new device: a pilot study

“…Laboratory tests, including CBCs with differential counts, chemistry (obtained as a panel consisting of electrolytes, glucose, ionized calcium, blood urea nitrogen, blood gases, and lactate), were evaluated twice weekly until discharge. We used a Nova Stat Profile‐M machine (Nova Biomedical Corporation, Waltham, MA, USA) as was previously described by us (6). Urinalysis, blood and urine cultures were evaluated weekly until discharge.…”