Serum concentrations of AY-hCG and PAPP-A
were analyzed and CRL and NT were measured at the time of routine screening for Down's Syndrome.
Both intact hCG-free and nonpurified sera were mixed with washed red blood cells and used to prepare blood spots, which were dried and then measured for PAPP-A
and free hCG[beta].
The distribution of serum hs CRP, PAPP-A
and MPO were non parametric so Mann-Whitney U test was applied.
Each laboratory was asked to combine its first-trimester PAPP-A
and NT results from a designated ICP specimen along with its own second-trimester marker results from a designated CAP Maternal Screening FP survey specimen (those samples include targeted concentrations of second-trimester [alpha]-fetoprotein, unconjugated estriol, hCG, and dimeric inhibin-A).
Differences of borderline significance in PAPP-A
and CRP were observed for patients with and without at least 1 high-grade lesion with a stenosis >95% (median 4.
The measurements of hCG[beta] and PAPP-A
were mainly between gestational day 63 and day 95, with at least 50 samples or more per day from each center, peaking on day 77 with nearly 600 samples (see online Supplemental Table S3).
We don't have data that are prospectively collected, but using mathematical modeling, we can predict that if you just use free [beta]-HCG and PAPP-A
with no nuchal translucency you would be able to pick up 52% of twin pregnancies discordant for Down and 55% of the ones concordant for Down.
Serum total PAPP-A
concentrations were measured with an ultrasensitive ELISA kit with polyclonal anti-PAPP-A
antibody (DRG International).
Existing commercial assays for PAPP-A
detect both complexed PAPP-A
/proMBP and the noncomplexed free form of PAPP-A
(FPAPP-A), and these total PAPP-A
(TPAPP-A) assays are the only ones that have been used so far in published clinical reports on PAPP-A
as a cardiac or ACS marker (1-4, 13, 14).
In the circulation of pregnant women, PAPP-A
predominantly exists as a 500-kDa heterotetrameric 2:2 complex with the proform of eosinophil major basic protein (proMBP), denoted PAPP-A
During pregnancy, PAPP-A
is found in circulation as a 2:2 heterotetramer covalent complex of PAPP-A
and the proform of the eosinophil major basic protein (proMBP) (9).
We did not investigate the stability of PAPP-A
in the SST tubes, and this was not remarked upon in either of the reports detailing the assay and analyte characteristics (4, 9) or within the manual provided by DSL.