The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 05, 1982
Filed:
Aug. 18, 1980
Holvor W Ashley, Burlingame, CA (US);
Vincent H Li, Maryland Heights, MO (US);
Sherwood Medical Industries Inc., St. Louis, MO (US);
Abstract
A method and apparatus for the detection of the magnitude of selected chemical substances in a biological fluid by fixed rate analysis. Photometric analysis is performed sequentially upon a standard solution and then upon an unknown sample to determine the rate reaction in each. The method and apparatus minimize or eliminate error in equipment drift and calibration. The rate reaction is manually initiated in a standard solution carrying a known amount of a chemical substance. The standard is then placed into a photodetector circuit to produce a voltage representing optical density which increases at a constant but unknown rate during the reaction. The time required for the voltage to change from a base-line level to a selected and pre-set value is then measured and stored as a calibration reference time. Then, the rate reaction in the sample carrying an unknown amount of the chemical substance is initiated and the standard is replaced by the sample in the same photodetector circuit to produce a voltage representing optical density of the unknown sample. The voltage representing the optical density of the unknown sample increases at a constant but unknown rate and the rate is proportional to the amount of chemical substance in the sample. The voltage level at the end of the calibration reference time represents the change in the optical density of the unknown sample which, in turn, indicates the amount of chemical substance in the sample with respect to the standard sample. The voltage level is then provided to a display which indicates the amount of the chemical substance in the sample.