Method and an apparatus for determining the number of particles or cells in a liquid sample

• US 6,157,692 A
• Filed: 06/29/1999
• Issued: 12/05/2000
• Est. Priority Date: 08/21/1995
• Status: Expired due to Term

• Current Assignee: Christian Born, Mogens Bering Larsen, Steen Kold Christensen, Tove Asmussen
• Original Assignee: Christian Born, Mogens Bering Larsen, Steen Kold Christensen, Tove Asmussen
• Inventors: Born, Christian, Christensen, Steen Kold, Asmussen, Tove, Larsen, Mogens Bering
• Primary Examiner(s): RUBIN, MARGARET R
• Application Number:
  US09/342,144
• Time in Patent Office: 525 Days
• Field of Search: 377/10, 377/12
• US Class Current: 377/10
• CPC Class Codes: G01N 15/1456 without spatial resolution of the texture or inner structure of the particle, e.g. processing of pulse signals
• CPC Class Codes: G01N 2015/1486 Counting the particles
• CPC Class Codes: G06M 11/00 Counting of objects distributed at random, e.g. on a surface

Abstract

A method and apparatus for determining the number of particles or cells in a liquid sample. The method comprises a) determining the number of particles or cells in a first volume of the liquid sample, b) determining the statistical uncertainty of the determined number of particles in said first volume, c) if the determined uncertainty is larger than a pre-determined value, determining the number of particles or cells in a further volume of the liquid sample, d) adding the numbers of cells or particles determined in steps a) and c), e) determining the statistical uncertainty of the number of particles determined in step d), f) repeating steps d) and e) with a further volumes of the liquid sample, until the uncertainty determined in step e) is lower than said pre-determined value or until a pre-determined total volume of the liquid sample in which the number of cells or particles has been determined exceeds a pre-determined volume being larger than said first volume. In this way, the volume examined and the uncertainty of the measurement may be selected so that a suitable compromise between the uncertainty and the time required to perform the measurement can be obtained. The apparatus according to the invention comprises a liquid flow system allowing the measurement sequence to be interrupted as soon as the calculating means decide that the uncertainty of the actual cell count is small enough to rely on the present determination. The apparatus will then be ready to carry on with the next sample, thereby maintaining a high capacity while obtaining reliable cell counts.

Claims

1. An apparatus for determining a number of particles or cells in a liquid sample, said apparatus comprising:

a first unit that determines the number of particles or cells in a first and (a) further volume(s) of the liquid sample,

said first unit further determining the statistical uncertainty of the determined number of particles or cells in a given volume of said liquid sample and determining whether the determined uncertainty is lower than a pre-determined value, and

a second unit that adds the numbers of particles or cells determined in said first and said further volumes of said liquid sample.

2. An apparatus for determining a number of particles or cells in a liquid sample, said apparatus comprising:

a unit that determines the number of particles or cells in a first and (a) further volume(s) of the liquid sample,

a waste unit for receiving the mixture of dye and liquid sample subsequent to the determination of the number of cells or particles in a volume of the sample,

wherein the waste unit includes at least two containers for receiving different parts of the mixture, a first container for receiving parts of the mixture where the concentration of dye is lower than a pre-selected concentration and a second container for receiving parts of the mixture where the concentration of dye is higher than the pre-selected concentration.