Median levels of serum biomarkers of fetal Down syndrome detected during the first trimester among pregnant Thai women

Abstract

Ethnic group-specific medians for PAPP-A and free β-hCG should be incorporated during first-trimester screening for fetal Down syndrome.

Normative weight-adjusted models for the median levels of first trimester serum biomarkers for trisomy 21 screening in a specific ethnicity

“…However, our results also differed from a study in northern Thailand [9], which found significantly higher levels of both maternal serum markers compared to our study. The assays in the northern Thailand study [9] were performed using the DELFIA Xpress Immunoanalyzer System (Perkin Elmer, Waltham, MA, USA).…”

“…However, our results also differed from a study in northern Thailand [9], which found significantly higher levels of both maternal serum markers compared to our study. The assays in the northern Thailand study [9] were performed using the DELFIA Xpress Immunoanalyzer System (Perkin Elmer, Waltham, MA, USA). The very high values of r for each prediction equation from northern Thailand [9] indicate that the equations were constructed by regressing the daily medians of the measured values against gestational age.…”

“…In each figure, the left upper side is the result of the quantile regression using the southern Thai data, the right upper side is based on the published equation for median value for a Caucasian population [8], and the left lower side is based on the published equation for a northern Thai population [9]. …”

“…The assays in the northern Thailand study [9] were performed using the DELFIA Xpress Immunoanalyzer System (Perkin Elmer, Waltham, MA, USA). The very high values of r for each prediction equation from northern Thailand [9] indicate that the equations were constructed by regressing the daily medians of the measured values against gestational age. Doing this, however, ignores the variability between subjects on each day that measurements are made.…”

“…The best fitting model for each of PAPP-A and free β-hCG was selected based on each predictor term making a statistically significant contribution (p<0.05) to the fit of the model. Surface plots depicting the predicted median levels of serum PAPP-A and free β-hCG against gestational age and maternal weight were constructed and compared with similar surfaces based on published data for Caucasian [8] and northern Thai populations [9]. Multiple of the median (MoM) values for serum PAPP-A and free β-hCG in our subjects were then calculated based on our predicted median values for southern Thai women using the appropriate gestational age and maternal weight, and then compared with the MoM values that would have been obtained using the corresponding predicted median values for Caucasian and northern Thai women.…”