Abstract: The present invention relates to calibration of a particle characterisation apparatus in which particles suspended in a liquid are passed through an orifice one by one for characterisation of the particles, for instance by Coulter counting. The calibration does not require utilisation of special calibration particles or liquids. A priori knowledge of the shape of a typical size distribution of a blood sample is utilised to adjust the apparatus based on an initial relatively short counting period of the sample in question. The initially determined size distribution is compared to the corresponding known typical size distribution and the apparatus is subsequently adjusted to counteract possible differences. Upon adjustment of the apparatus, the remaining part of the sample is passed through the orifice for determination of the actual particle size distribution of the remaining sample.

Abstract: With a method of establishing an enveloped flow in a channel, in the channel an envelopment area (3) with a channel section (6, 7) is configured to which a stub with an outlet is connected, where the stub, which can be configured as a polyhedron, is arranged substantially at right-angles to the envelopment area and with the plane of the outlet substantially at right-angles to the channel section. An inlet channel (9, 11) and an outlet channel (8, 10) are connected to the envelopment area. By providing a narrowing-down in the cross-section of the channel in immediate extension of the envelopment area (3), a hydrodynamic focussing of the sample fluid is achieved when a fluid, such as a sample fluid, is introduced into the stub, and a carrier fluid is introduced into the inlet channel. The advantage of the invention is that since it is necessary only to have two fluid inlets, a relatively simple structure can be established, which can be built up in a monolithic manner, e.g. by injection molding.

Abstract: The present invention relates to a lysing reagent for use in the simultaneous automatic electronic enumeration and volumetric discrimination of different types of blood cells, such as leukocytes, thrombocytes, etc, in blood. Further, the present invention relates to a Coulter (impedance) counting apparatus containing the lysing reagent, for example a Coulter counting apparatus with a disposable cartridge for characterizing cells suspended in a liquid, especially a self-contained disposable cartridge for single-use analysis, such as for single-use analysis of a small quantity of whole blood.

Abstract: The present invention relates to a disposable cartridge for characterizing particles suspended in a liquid, especially a self-contained disposable cartridge for single-use analysis, such as for single-use analysis of a small quantity of whole blood. The self-contained disposable cartridge facilitates a straightforward testing procedure, which can be performed by most people without any particular education. Furthermore, the apparatus used to perform the test on the cartridge is simple, maintenance free, and portable.

Abstract: The present invention relates to a particle characterization apparatus in which particles suspended in a liquid passes through an orifice or aperture for detection and characterization of the particles utilising impedance determination. In particular the invention relates to utilisation of a membrane of a polymer as a base material for precision machining of a sub-millimetre orifice. Forming the orifice in a polymer membrane facilitates the construction of a single use cartridge for haematology analysis due to low material and production costs.

Abstract: With a method of establishing an enveloped flow in a channel, in the channel an envelopment area (3) with a channel section (6, 7) is configured to which a stub with an outlet is connected, where the stub, which can be configured as a polyhedron, is arranged substantially at right-angles to the envelopment area and with the plane of the outlet substantially at right-angles to the channel section. An inlet channel (9, 11) and an outlet channel (8, 10) are connected to the envelopment area. By providing a narrowing-down in the cross-section of the channel in immediate extension of the envelopment area (3), a hydrodynamic focussing of the sample fluid is achieved when a fluid, such as a sample fluid, is introduced into the stub, and a carrier fluid is introduced into the inlet channel. The advantage of the invention is that since it is necessary only to have two fluid inlets, a relatively simple structure can be established, which can be built up in a monolithic manner, e.g. by injection moulding.