Performance of free beta-human chorionic gonadotrophin (free beta-hCG) and pregnancy associated plasma protein-A (PAPP-A) analysis between Delfia Xpress and AutoDelfia systems in The Netherlands.
BACKGROUND
The VU University Medical Center (VUmc) was the first hospital in the Netherlands to introduce the Delfia Xpress for the analysis of free beta-human chorionic gonadotrophin (beta-hCG) and pregnancy associated plasma protein-A (PAPP-A) in the first trimester screening program for Down syndrome. Since then, others have implemented this system. In this study, we tested the equality of measurements for free beta-hCG and PAPP-A between Delfia Xpress systems and one AutoDelfia system.


METHODS
A total of 40 serum samples were aliquoted and stored at -20 degrees C. Samples were analyzed by six Delfia Xpress systems and one AutoDelfia system over a time period of 2 years.


RESULTS
The relationships between free beta-hCG and PAPP-A were excellent for the different Delfia Xpress systems (r>0.99, p<0.0001). For PAPP-A, the agreement between the main system at VUmc and five other systems was linear with slopes between 0.99 and 1.06. Similarly, agreement for free beta-hCG was linear with slopes between 0.99 and 1.09. Likewise, agreement for PAPP-A and free beta-hCG was excellent for the AutoDelfia vs. the main Delfia Xpress at the VUmc (r>0.99, p<0.0001). For both PAPP-A and free beta-hCG, the relationships were linear with slopes of 1.08 and 1.07.


CONCLUSIONS
We demonstrate an excellent agreement for the analysis of PAPP-A and free beta-hCG between Delfia Xpress systems and one AutoDelfia system.
Linskens
Ingeborg H
IH
Department of Obstetrics and Gynecology, VU University Medical Center, Amsterdam, The Netherlands.
Levitus
Marieke
M
Frans
Anneke
A
Schielen
Peter C J I
PC
van Vugt
John M G
JM
Blankenstein
Marinus A
MA
Dijstelbloem
Hilde M
HM
D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D009426:Netherlands; D011237:Predictive Value of Tests; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D018997:Chorionic Gonadotropin, beta Subunit, Human; D011933:Reagent Kits, Diagnostic; D011266:Pregnancy-Associated Plasma Protein-A