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PLoS One. 2015 Sep 10;10(9):e0137768. doi: 10.1371/journal.pone.0137768. eCollection 2015.

Perfluoroalkyl Acid Concentrations in Blood Samples Subjected to Transportation and Processing Delay.

Author information

1
Perinatal Epidemiology Research Unit, Aarhus University Hospital, Aarhus, Denmark.
2
Perinatal Epidemiology Research Unit, Aarhus University Hospital, Aarhus, Denmark; Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark.
3
Department of Environmental Science, Aarhus University, Roskilde, Denmark.
4
Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark.
5
Department of Obstetrics and Gynecology, Aarhus University Hospital, Aarhus, Denmark.
6
Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark; Department of Epidemiology, Fielding School of Public Health, University of California Los Angeles, California, United States of America.
7
Research Unit for Obstetrics and Gynecology, Institute of Clinical Research, University of Southern Denmark, Odense, Denmark.

Abstract

BACKGROUND:

In studies of perfluoroalkyl acids, the validity and comparability of measured concentrations may be affected by differences in the handling of biospecimens. We aimed to investigate whether measured plasma levels of perfluoroalkyl acids differed between blood samples subjected to delay and transportation prior to processing and samples with immediate processing and freezing.

METHODS:

Pregnant women recruited at Aarhus University Hospital, Denmark, (n = 88) provided paired blood samples. For each pair of samples, one was immediately processed and plasma was frozen, and the other was delayed and transported as whole blood before processing and freezing of plasma (similar to the Danish National Birth Cohort). We measured 12 perfluoroalkyl acids and present results for compounds with more than 50% of samples above the lower limit of quantification.

RESULTS:

For samples taken in the winter, relative differences between the paired samples ranged between -77 and +38% for individual perfluoroalkyl acids. In most cases concentrations were lower in the delayed and transported samples, e.g. the relative difference was -29% (95% confidence interval -30; -27) for perfluorooctane sulfonate. For perfluorooctanoate there was no difference between the two setups [corresponding estimate 1% (0, 3)]. Differences were negligible in the summer for all compounds.

CONCLUSIONS:

Transport of blood samples and processing delay, similar to conditions applied in some large, population-based studies, may affect measured perfluoroalkyl acid concentrations, mainly when outdoor temperatures are low. Attention to processing conditions is needed in studies of perfluoroalkyl acid exposure in humans.

PMID:
26356420
PMCID:
PMC4565678
DOI:
10.1371/journal.pone.0137768
[Indexed for MEDLINE]
Free PMC Article

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