Transportation of maternal serum specimens for screening for chromosomal aneuploidies: effect of seasonal variations, distance, and freezing on the stability of the biological markers.
OBJECTIVE
We studied the stability of maternal serum markers for screening for Down syndrome [alpha-fetoprotein (AFP), unconjugated estriol (uE3), total human chorionic gonadotropin (hCG), and free beta-human chorionic gonadotropin] following transportation.


METHODS
For each gestational week between 14 and 18 weeks, we collected about 50 samples for each possible combination of three potential sources of variation during transportation: season (winter/summer), sample frozen/fresh (prior to analysis) and origin (local or referred in) for a total of 1845 specimens. Commercial assays were used (IMx, Abbott for AFP and total hCG; AutoDelfia and Wallac for free beta-hCG and AFP; and radioimmunoassay Ortho-Clinical Diagnostics, for uE3).


RESULTS
Results of both total and free beta-hCG were significantly higher when samples were collected during summer and when they were sent to the laboratory from extramural blood drawing sites (multifactorial ANOVA, p < 0. 007).


CONCLUSIONS
We conclude that both total and free beta-hCG can be adversely affected during transportation. The resulting higher concentrations of these markers may increase the false positive rate of prenatal screening programs for aneuploidies.
Research Center, CHUQ-Hôpital Saint-François d'Assise, Québec City, Québec, Canada.
J
J
Massé
A
A
Summers
G
G
Cherian
J
J
Forest
D015415:Biomarkers / Q000097:blood; D001800:Blood Specimen Collection; D006063:Chorionic Gonadotropin / Q000097:blood*; D004314:Down Syndrome; D004964:Estriol / Q000097:blood*; D005260:Female; D005820:Genetic Testing; D006801:Humans; D011247:Pregnancy; D012621:Seasons; D013696:Temperature; D014186:Transportation; D000509:alpha-Fetoproteins / Q000032:analysis*
D015415:Biomarkers; D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol