Two stage calibration and analyte measurement scheme for spectrophotomeric analysis
US5891024A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 9, 1997 |
| Grant date | Apr 6, 1999 |
| Priority date | — |
| Expiry date | Apr 9, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N33/726
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A two-stage statistical calibration and measurement method and system is disclosed for performing photoplethysmographic measurement of blood analyte concentrations. Concentrations in a tissue sample of MetHb, O.sub.2 Hb, RHb and COHb are estimated by first estimating a concentration of MetHb (in a first stage) and subsequently, if the concentration of MetHb is within a predetermined range, then the estimated concentration of MetHb is assumed to be accurate and this estimated concentration of MetHb is utilized as a "known value" in determining the concentrations of the remaining analytes O.sub.2 Hb, RHb and COHb (in a second stage). That is, by eliminating one "unknown" from the system of equations, these remaining analytes can be calculated with increased accuracy. Each stage is performed using data obtained by transmitting light through the tissue sample (typically a finger or earlobe). The transmitted light is generated by four discrete light emitters, each emitter having a distinct spectral content.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.