Performance characteristics of Elecsys free βhCG and PAPP-A for first trimester trisomy 21 risk assessment in gestational weeks 8+0 to 14+0

Abstract

Screening for fetal trisomy 21 (T21) in the first trimester includes analysis of the serological markers pregnancy-associated plasma protein A (PAPP-A) and free β-choriogonadotropin (free βhCG). With the recent launch of these assays on the cobas e and Elecsys platforms, we investigated their clinical and analytical performance.We conducted a multicenter study in 5397 pregnancies including 108 cross-sectional collected repository cases with verified fetal T21 at 8–14 weeks of gestation. A technical validation of the Roche ElecsysThe imprecision of the Elecsys free βhCG and PAPP-A assays was between 1.0% and 2.8%, and both assays showed correlation to Kryptor (free βhCG 0.981; PAPP-A 0.987), AutoDELFIA (free βhCG 0.995; PAPP-A 0.979) and IMMULITE assays (free βhCG 0.983; PAPP-A 0.983). With a cut off at 1:300 the overall sensitivity of the screening including nuchal translucency reached 94% for a 3% false positive rate.The Roche Elecsys free βhCG and PAPP-A are suitable and reliable assays for first trimester T21 risk assessment. Both assays were approved and recommended by the FMF.

Effect of ethnicity on first trimester biomarkers for combined trisomy 21 screening: results from a multicenter study in six Asian countries

“…Day‐specific and site‐specific medians of free βhCG and PAPP‐A of the six different Asian countries as well as regressed medians of the Asian and European populations are presented in Figure . The regressed medians of the European population are derived from an earlier study . PAPP‐A levels scatter narrower compared with the free βhCG values, and there were no noticeable differences between different countries (not shown).…”

“…The regressed medians of the European population are derived from an earlier study. 5 PAPP-A levels scatter narrower compared with the free βhCG values, and there were no noticeable differences between different countries (not shown). Dayspecific medians of the whole Asian study population are provided in the Supporting Information Table 1.…”

“…In our study, c 1 is 74.9439 and 59.0110 for PAPP‐A and free βhCG, respectively. The difference in MoM values of the biochemical markers between the European reference group from the multicenter evaluation and the Asian population after weight correction was evaluated using the median test with a 10% difference. Differences between Asian countries were qualitatively compared before and after bodyweight adjustment.…”

“…In 2007, Roche Diagnostics introduced tests for the detection of free βhCG and PAPP‐A used in first trimester T21 risk assessment dedicated to be run on Roche Diagnostics' cobas e and Elecsys analyzers. The corresponding clinical data were generated in an international multicenter study performed at seven European sites including prospective and retrospective collected samples from pregnant healthy women (mainly Caucasians) with a normal pregnancy outcome without complications as well as samples from T21 pregnancies …”

“…The corresponding clinical data were generated in an international multicenter study performed at seven European sites including prospective and retrospective collected samples from pregnant healthy women (mainly Caucasians) with a normal pregnancy outcome without complications as well as samples from T21 pregnancies. 5 Previous studies have shown that between different populations, there are small but statistically significant differences in the median values of free βhCG and PAPP-A. 6,7 Spencer et al 7 compared a data set of 4835 South Asian pregnant women (Indian, Pakistani, and Bangladeshi) and a data set of 3925 Oriental pregnant women (Chinese, Korean, and Japanese) with a reference group of 61 219 Caucasian pregnant women.…”