Calidad de la muestra y niveles de fenilalanina y 17-hidroxiprogesterona en pesquisa neonatal

Quality of the sample and phenylalanine and 17-hydroxyprogesterone levels in neonatal screening. In the programs for neonatal screening many different analytes are quantified from dried blood on filter paper cards. Several factors affect the quality of the samples invalidating their employment in the laboratory: inadequate co- llection procedures, quality of the filter paper, the drying, storage and transportation under extreme environmental conditions. This article aims to show how the quality of the sample collection influences the phenylalanine (Phe) and 17-hydroxyprogesterone (17-OHP) levels. As such, samples of newborns on filter paper from Ramon Gonzalez Coro Hospital were collected and analyzed.The blood spots from a sample were classified according to their appearance, satisfactory spot (MV) or unsatisfactory spot (MNV). Phe and 17OHP levels were determinated by UMTEST PKU and UMELISA 17OH Progesterone NEONATAL, respectively. 19.5% of 3043 newborns samples exhibited unsatisfactory spots. Concordance correlations studies between MV y MNV showed the precision and accuracy were affected by quality of the samples. False positive and negative values (with concerning control sample) were detected from sam- ples with MNV. The correct application of collection procedures for samples is essential in obtaining reliable results in screening neonatal laboratories.