Adaptation of alpha-fetoprotein and intact human chorionic gonadotropin fluoroimmunometric assays to dried blood spots.
BACKGROUND
Although dried blood spots (DBS) are very convenient for massive screening, there are very few examples of their application in maternal serum screening of Down's syndrome and neural tube defects. For large-scale mass population screening in Brazil, a continental country, DBS would be fairly recommended. As there are no easily available commercial assays of AFP and hCG in DBS, the Wallac Delfia fluoroimmunometric assays intended for these biochemical markers were adapted to DBS.


METHODS
Serum specimens and DBS obtained from 116 pregnant women were analyzed by conventional methodology and by the adapted assays, respectively. Precision (within-run and between-run), recovery and detection limits studies were conducted


RESULTS
The non-linear regression fit of the levels of AFP and hCG in DBS by gestational age in days was described. There was a strong statistically significant correlation between the levels of these analytes in serum specimens and in DBS. For both analytes, the precision variances were compared to those presented by the manufacturer for serum samples.


CONCLUSIONS
It is feasible to use these DBS adapted assays in maternal serum screening programs.
Vieira Neto
Eduardo
E
DLE Laboratory, Rio de Janeiro, RJ, Brazil. eduardo.vieira.neto@terra.com.br
Carvalho
Eulália C D
EC
Fonseca
Armando
A
D001774:Blood Chemical Analysis / Q000379:methods; D006063:Chorionic Gonadotropin / Q000097:blood*; D005260:Female; D015200:Fluoroimmunoassay / Q000379:methods*; D006801:Humans; D011247:Pregnancy; D000509:alpha-Fetoproteins / Q000032:analysis*
D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins