Biosensing meter with fail/safe procedures to prevent erroneous indications
US5352351A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1993 |
| Grant date | Oct 4, 1994 |
| Priority date | — |
| Expiry date | Jun 8, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/3273
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A biosensing meter receives a sample strip that includes electrically isolated sense and excitation electrodes bridged by a reaction zone. When a drop of biological sample fluid is placed in the reaction zone, a plurality of fail/safe tests are performed. A drop size test is performed by a circuit that detects the size of the drop placed in the reaction zone. The circuit both detects that a drop has been placed in the reaction zone and further measures a test current level, after a delay, to determine that the drop size is sufficient to enable hydration of reactants in the reaction zone. Subsequently, during the reaction, a "delta" current change is measured at succeeding sample time. This test measures the difference between succeeding current samples during a measurement time. If each succeeding sample is not less than preceding sample by a delta value, a determination is made that the current is not monotonically decreasing and the test is aborted. At the termination of the measurement time, a current sum test is performed wherein a processor calculates a linear sum of all sample test currents and calculates a ratio between that sum and the last current sample. If that ratio mat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.