Granted Patent
Utility
US 4,477,346 · App. 06/487,896
Method for the removal of interfering substances in theophylline assays
Inventors:
Johanne C. Dickinson, William A. Frey
Patented Case
View Patent ↗
Granted: Oct 16, 1984
Filed: Apr 22, 1983
Inventors
Johanne C. Dickinson
William A. Frey
Assignee (at issue)
E.I. DU PONT DE NEMOURS AND COMPANY
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.