Accurate and precise bilirubin and albumin measurements are essential for proper management of jaundiced neonates. Data hereon are lacking for Dutch laboratories. We aimed to determine variability... Show moreAccurate and precise bilirubin and albumin measurements are essential for proper management of jaundiced neonates. Data hereon are lacking for Dutch laboratories. We aimed to determine variability of measurements of bilirubin and albumin concentrations typical for (preterm) neonates. Aqueous, human serum albumin-based samples with different concentrations of bilirubin (100, 200, 300, 400, and 500 and 30 g/L) were sent to laboratories of all Dutch neonatal intensive care units ( of the specimens were measured using locally available routine analytical methods. The mean, standard deviation, and coefficients of variations (CV) were calculated per sample. Bilirubin concentrations were underestimated in the absence of albumin (maximal CV 26.0%). When the albumin concentration was 10 or 20 g/L, the bilirubin concentrations of the samples were overestimated (maximal CV 14.1% and 9.2%, respectively). Variability increased with higher weighed-in bilirubin concentrations. Measured albumin levels were ~10% lower than albumin levels of manufactured samples. Bilirubin concentration did not influence albumin measurements. The maximal CV was 6.8%. In conclusion, interlaboratory variability of bilirubin and albumin measurements is high. Recalibration and introduction of a specific quality assessment scheme for neonatal samples is recommended to ensure exchangeability of bilirubin and albumin measurements among laboratories and to control the observed large variability.μmol/L) and albumin (0, 10, 15, 20, 25,n=10). Bilirubin and albumin recoveries Show less
In this thesis fetal fluid and protein dynamics are investigated to gain insight in fetal (patho-)physiology. Studies were performed in fetuses with severe anemia and/or hydrops fetalis.... Show moreIn this thesis fetal fluid and protein dynamics are investigated to gain insight in fetal (patho-)physiology. Studies were performed in fetuses with severe anemia and/or hydrops fetalis. Measurements were performed in fetal blood or amniotic fluid, obtained before or during intrauterine transfusion. The severity of anemia can be predicted by measurement of bilirubin in amniotic fluid. We showed that this concentration is based on bilirubin in fetal blood and on albumin concentrations. Albumin in amniotic fluid is most probably not of fetal however of membrane or maternal origin. Thus, bilirubin seems to exchange between albumin in fetal blood and amniotic fluid over the intramembraneous pathway. Low albumin concentration in fetal blood seems to be a secondary effect of hydrops fetalis. Fetuses with severe anemia were found to maintain their total blood volume. Thus, the decrease in red cell volume is compensated by an increase in plasma volume. This could explain the decrease in albumin concentration. During intrauterine transfusion, part of the plasma volume leaves the circulation. It is expected that this process continues after transfusion, thus further increasing the hematocrit. Acquired insights and differences between fetuses and neonates are discussed. Finally, implications for current practice and future research are described. Show less
