Plasma free fatty acid reference interval in South African neonates in the first week of life

Background Non-esterified fatty acid (NEFA) levels are an important diagnostic tool in the investigation of neonatal hypoglycaemia. NEFA reference intervals have not been reported for neonates previously. Methods The objective of this study was to determine an NEFA reference interval for neonates. Results Heparinized plasma obtained from 106 healthy neonates in the first week of life was analysed using the Roche “Free fatty acid, Half-micro test” kit. Results were then analysed statistically for normality (Shapiro–Wilk test) and reference interval determined non-parametrically (bootstrap method). Conclusions NEFA levels displayed a non-Gaussian distribution and the reference interval (2.5th and 97.5th percentiles) was 0.2–1.5 mmol/L (90% confidence intervals 0.1–0.3 and 1.4–2.0 mmol/L, respectively). The NEFA reference interval in South African neonates less than a week old is similar to that described in infants (1–12 months), indicating that this reference range can be used over the entire neonatal period.