METHOD FOR ASCERTAINING A TRANSMISSION VALUE

• US 20140147928A1
• Filed: 11/25/2013
• Published: 05/29/2014
• Est. Priority Date: 11/27/2012
• Status: Active Grant

• Current Assignee: Siemens Healthcare Diagnostics Products GmbH (Siemens AG)
• Original Assignee: Siemens Healthcare Diagnostics Products GmbH (Siemens AG)
• Inventors: Steinebach, Wolfgang
• Granted Patent: US 9,664,670 B2
• Time in Patent Office: Days
• US Class Current: 436/164
• CPC Class Codes: G01N 21/59 Transmissivity G01N21/25 takes precedence
• CPC Class Codes: G01N 2201/0696 Pulsed
• CPC Class Codes: G01N 33/5002 Partitioning blood components

Abstract

The invention is in the field of in vitro diagnostics and relates to a method for ascertaining a transmission value for a light signal that is pulsed at a frequency through a specimen in an automatic analysis appliance. It also relates to a transmission measurement apparatus for an automatic analysis appliance, comprising a light source that is pulsed at a frequency and a photodetector having a downstream A/D converter.

Claims

1. A method for ascertaining at least one transmission value for a light signal that is pulsed at a frequency through a specimen (8) in an automatic analysis appliance, having the following steps:

a) a voltage curve (22) associated with the intensity of the light signal transmitted by the specimen (8) is produced,

b) a plurality of sample values (32, 34, 36) for the voltage curve (22) are ascertained,

c) a first voltage value associated with a light pulse is ascertained from a number of sample values (34), and a second voltage value associated with a dark time between two light pulses is ascertained from a number of sample values (36), wherein the sample values (36) for ascertaining a second voltage value associated with a dark time between two light pulses are offset from the sample values (34) for ascertaining a first voltage value associated with a light pulse by an integer multiple of a half-period corresponding to the frequency of the pulsed light signal, and

d) the second voltage value is subtracted from the first voltage value,

wherein the difference obtained in step d) is proportional to the transmission value.

2. The method as claimed in claim 1, in which sample values (32) in a prescribed transition region between light pulse and dark time are rejected in step c).

3. The method as claimed in claim 1, in which the respective dark time follows the respective light pulse directly or precedes the respective light pulse directly.

4. The method as claimed in claim 1, in which steps b), c) and d) are cyclically repeated and a mean value is formed over the transmission values ascertained in step d).

5. A method for determining the concentration or activity of at least one analyte in a specimen, characterized in that the concentration or activity of the at least one analyte is determined by using at least one transmission value that is determined using a method as claimed in claim 1.

6. The method as claimed in claim 5, wherein the concentration or activity of the analyte is determined in a body fluid specimen, preferably in full blood, blood plasma, serum, liquor or urine.

7. A transmission measurement apparatus (1) for an automatic analysis appliance, comprising a light source (6) that is pulsed at a frequency, a photodetector (10) having a downstream A/D converter (31) with a sampling frequency that corresponds to an even multiple of the frequency of the pulsed light source, and also an integrated circuit that is connected downstream of the A/D converter (31) and that is designed to

i) associate sample values from the A/D converter (31) with a light pulse or with a dark time between two light pulses on the basis of the frequency of the pulsed light source and phase, and

ii) delay the sample values (34) associated with the light pulses or the sample values (36) associated with the dark times by an integer multiple of a half-period corresponding to the frequency of the pulsed light source, and

iii) subtract resultant simultaneous sample values (32) from one another.

8. The transmission measurement apparatus (1) as claimed in claim 7, in which the sampling frequency has at least four times the value of the frequency of the pulsed light source (6).

9. The transmission measurement apparatus (1) as claimed in claim 7, in which the integrated circuit is designed to form a mean value over the subtracted simultaneous sample values (32).

10. The transmission measurement apparatus (1) as claimed in claim 7, in which the integrated circuit contains a field programmable gate array (FGPA).

11. An automatic analysis appliance having a transmission measurement apparatus (1) as claimed in claim 7.