Background: The preparation of a standard bilirubin is essential for an adequate quality control of laboratorial bilirubinemia measurements because they are subjected to a large variability in results depending on the dosage method used and the lack of a rigorous standardization of its performance. Once prepared, this standard solution has to be divided in aliquots and stored to be routinely used. Objective: To evaluate the effect of different conditions of the standard solution storage in the stability of bilirubin with the purpose of using it for calibration of equipment used in the dosage of bilirubin in neonates. Methods: After the preparation of standard solution with 25mg/dl of bilirubin, it was stored under 4°C or frozen under - 20°C and - 70°C. During the next nine months, consecutive bilirubin dosages of the standard solution were performed and the results analyzed through the Anova-two-ways. Results: The samples frozen under - 70°C did not present a significant degradation during nine months, while those under - 20°C and 4°C suffered a degradation of 5% and 24,18% of bilirubin levels, respectively, during the period of three months. Conclusion: Storage of standard bilirubin solution under - 70°C is recommended for the maintenance of constant bilirubin concentration.
Bilirubin; Bilirubin standard; Jaundice; Hyperbilirubinemia
