Metabolic profile of amniotic fluid as a biochemical tool to screen for inborn errors of metabolism and fetal anomalies.

Physiologic concentration in amniotic fluid (AF) of several metabolites has not been established with certainty. In this study, we initially assayed purines, pyrimidines, and amino compounds in 1,257 AF withdrawn between the 15th and the 20th week of gestation from actually normal pregnancies (normal gestations, normal offspring). Results allowed to determine physiologic reference intervals for 45 compounds. In these AF, not all purines and pyrimidines were detectable and uric acid (238.35±76.31 µmol/l) had the highest concentration. All amino compounds were measurable, with alanine having the highest concentration (401.10±88.47 µmol/l). In the second part of the study, we performed a blind metabolic screening of AF to evaluate the utility of this biochemical analysis as an additional test in amniocenteses. In 1,295 additional AF from normal pregnancies, all metabolites fell within the confidence intervals determined in the first part of the study. In 24 additional AF from women carrying Down's syndrome-affected fetuses, glutamate, glutamine, glycine, taurine, valine, isoleucine, leucine, ornithine, and lysine were different from physiologic reference values. One AF sample showed phenylalanine level of 375.54 µmol/l (mean value in normal AF=65.07 µmol/l) and was from a woman with unreported phenylketonuria with mild hyperphenylalaninemia (serum phenylalanine=360.88 µmol/l), carrying the IVS 4+5 G-T and D394A mutations. The fetus was heterozygote for the maternal D394A mutation. An appropriate diet maintained the mother phenylalanine in the range of normality during pregnancy, avoiding serious damage in fetal and neonatal development. These results suggest that the metabolic screening of AF might be considered as an additional biochemical test in amniocenteses useful to highlight anomalies potentially related to IEM.

Serological determinants of COVID-19.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection spreaded rapidly worldwide, as far as it has become a global pandemic. Therefore, the introduction of serological tests for determination of IgM and IgG antibodies has become the main diagnostic tool, useful for tracking the spread of the virus and for consequently allowing its containment. In our study we compared point of care test (POCT) lateral flow immunoassay (FIA) vs automated chemiluminescent immunoassay (CLIA), in order to assess their specificity and sensibility for COVID-19 antibodies detection. RESULTS: We find that different specificities and sensitivities for IgM and IgG tests. Notably IgM POCT FIA method vs CLIA method (gold standard) has a low sensitivity (0.526), while IgG POCT FIA method vs CLIA method (gold standard) test has a much higher sensitivity (0.937); further, with respect of IgG, FIA and CLIA could arguably provide equivalent information. CONCLUSIONS: FIA method could be helpful in assessing in short time, the possible contagiousness of subjects that for work reasons cannot guarantee "social distancing".