Clinical Chemistry
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Clinical Chemistry 49: 935-939, 2003; 10.1373/49.6.935
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Web of Science (3)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Grenache, D. G.
Right arrow Articles by Gronowski, A. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Grenache, D. G.
Right arrow Articles by Gronowski, A. M.
Related Collections
Right arrow General Clinical Chemistry
(Clinical Chemistry. 2003;49:935-939.)
© 2003 American Association for Clinical Chemistry, Inc.

Preanalytical Factors That Influence the Abbott TDx Fetal Lung Maturity II Assay

David G. Grenache1, Curtis A. Parvin1 and Ann M. Gronowskia,1

1 Washington University School of Medicine, Department of Pathology and Immunology, Division of Laboratory Medicine, Box 8118, 660 S. Euclid Ave., St. Louis, MO 63110.

aAuthor for correspondence. Fax 314-362-1461; e-mail gronowski{at}pathbox.wustl.edu.

Background: The TDx Fetal Lung Maturity II (FLM II) assay uses amniotic fluid to assess lung maturity of the unborn infant. We investigated common preanalytical factors that influence FLM results, including centrifugation, sample storage, and contamination by whole blood.

Methods: We tested 18 specimens after centrifugation and after resuspension by vortex-mixing. We also analyzed 23 specimens stored at -20 °C for up to 448 days and then thawed (duplicate measurements), 20 specimens stored at 4 °C, and 24 specimens stored at room temperature. In addition, we evaluated the effects of whole blood diluted into 19 different specimens.

Results: Centrifugation significantly decreased FLM II results from baseline (P <0.0001), and resuspension returned results to baseline values (P = 0.286). Storage at -20 °C produced highly variable results that demonstrated a nonsignificant negative trend associated with storage time. Specimens were stable for 24 h when stored at 4 °C and 16 h at room temperature. Blood contamination produced significantly positive differences in results only in specimens with baseline values <=39 mg/g with a 5.8 mg/g increase in FLM II for every 0.1 x 1012/L increase in the erythrocyte count (slope = 58.4).

Conclusions: Resuspension of centrifuged specimens produces clinically valid FLM II results. Results from specimens stored at -20 °C can be highly variable and decrease over time. Results from specimens stored at 4 °C and at room temperature are stable for 24 and 16 h, respectively. Blood contamination up to 0.03 x 1012 erythrocytes/L is acceptable for FLM II analysis.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2003 by the American Association for Clinical Chemistry.