Year: 2009
Type: conference-abstract
Abstract: To study the stability of PAPP-A and free hCGβ in first trimester maternal serum under typical storage conditions and times. The most effective risk assessment of fetal aneuploidy is first trimester maternal serum PAPP-A and free hCGβ measurements combined with nuchal translucency measurements and maternal history. Due to the variation in storage conditions and transportation times for individual clinical samples, and the long term storage at − 20 °C and repeat freeze-thawing of research samples, it is essential to establish the stability of these analytes. Excess serum from a routine screening clinic was pooled, aliquoted and stored at one of the following storage temperatures: − 20 °C, 4 °C, room temperature (RT) or 30 °C. Aliquots from each pool were measured for PAPP-A and free hCGβ using the AutoDELFIA (AD) and DELFIA Xpress (DX) systems (PerkinElmer, Turku, Finland) at t = 0 and various time points after. Other aliquots were measured after up to six − 20 °C to RT freeze-thaw cycles. In all temperatures studied except − 20 °C, PAPP-A and free hCGβ measurement concentrations showed positive correlation with storage time on both DELFIA systems. When measured on the AD, PAPP-A and free hCGβ were respectively stable in serum for 20 and 1 days at 30 °C, 37 and 3 days at RT, 142 and 94 days at 4 °C when a 10% change in concentration is considered acceptable. The results obtained from − 20 °C showed no clear concentration change during the period of 210 days. DX measurements were roughly in line with the AD. Six repeated freeze-thaw cycles did not significantly effect either analytes on either DELFIA platform. PAPP-A and free hCGβ were shown to be stable in serum for normal use when stored at 4 °C and − 20 °C when measured on the AD and DX analysers. Attention needs to be paid to serum samples stored at RT or warmer with regards to the measurement of free hCGβ.
DOI: 10.1002/uog.7034
Authors: N. Cowans, A. Stamatopoulou, K. Spencer, P. Aronkyto, J. Hellstrom, P. Kankaanpää
Institution: PerkinElmer (Finland)
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2068284168