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Method of validating and/or calibrating devices used for carrying out photometry of living tissues and a device for implementing said method

  • US 5,891,025 A
  • Filed: 02/24/1997
  • Issued: 04/06/1999
  • Est. Priority Date: 08/22/1994
  • Status: Expired due to Fees
First Claim
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1. A process for in vitro validation of a photometric device, said method comprising:

  • (a) specifying a substance of a body fluid to be measured;

    (b) adjusting a parameter of said substance of a body fluid in body fluid in vitro;

    (c) providing adjusted body fluid from step (b) to a measuring area within a measuring cell such that at least some of said adjusted body fluid is between a radiation emitter and a radiation receiver, wherein at least one of said radiation emitter and radiation receiver is immersed within said body fluid, and wherein the mean light path between the radiation emitter and radiation receiver corresponds to the effective absorption length;

    (d) transilluminating the body fluid in the measuring area;

    (e) actively and in a defined manner periodically changing the effective absorption length through the body fluid between the radiation emitter and receiver, without using the body fluid as a medium for transmission of forces;

    (f) detecting changes in light intensity of at least two spectral frequencies which are characteristic absorption frequencies for said substance of a body fluid to be detected, said changes constituting a ratio "Ω

    " of said substance of a body fluid to be detected, wherein Ω

    is defined with the following equation;

    ##EQU28## (g) determining a correlation between (i) said ratio Ω and

    (ii) a parameter of said substance of a body fluid.

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