ABSTRACT

To compare the serum and salivary values of alpha-fetoprotein (AFP) used in screening neural tube defects (NTD) during pregnancy. To investigate whether saliva can be used instead of serum in NTD screening.

The study was conducted between May 2018 - November 2019 at Adıyaman University. The study included 41 pregnant women complicated by NTD and 44 healthy pregnant women. Three ml venous blood and 2 ml saliva samples were taken from both groups. Serum and saliva samples were not diluted. AFP concentration was measured at 450 nm by using commercially available enzyme-linked immunoassay. The intra‐ , and inter- test assay coefficients (CVs) of the kit were <8% and <10%, respectively. SPSS 21 program was used for data analysis. Mann-Whitney Test was used for the analysis of continuously changing parameters. The correlation coefficient was calculated by Spearman test. A p value of less than 0.05 was accepted for statistical significance.

When serum and salivary AFP values were compared between the two groups, the AFP values were found to be higher in both NTD group samples (p<0.001, p<0.001). In both groups, correlation analysis for serum and salivary AFP values showed a strong positive correlation (r=0.730, p<0.001). When the cut-off value for serum AFP is taken as 0.26, NTD can be determined with 100% sensitivity and 90% specificity (AUC: 0.932, p<0.001). When the cut-off value for salivary AFP is taken as 0.034, it can detect NTD with 95% sensitivity and 92% specificity (AUC: 1.00, p<0.001).

Salivary and serum AFP values showed strong positive correlation between themselves. We believe that saliva can be used in NTD screening performed by AFP measurement.

Keywords: neural tube defect, alpha-fetoprotein, saliva, anomaly, screening test