A method for determining the thrombocyte count in a capillary blood sample, comprising the steps of: providing a capillary blood sample subjected to anticoagulant treatment with EDTA at sample collection; diluting said sample by a dilution factor of 1:10 to 1:2000, in a non-lytic buffer in the presence of an amount of EDTA efficient for reducing platelet aggregation; incubating the diluted sample for a duration of at least 23 s; optionally, diluting the incubated sample in a second dilution step prior to determining the thrombocyte count from the incubated sample; and determining the thrombocyte count from the incubated sample. The method is performed in an integrated device. A device for performing the method.

Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

The present invention comprises methods and systems that use acoustic radiation pressure.

The present invention comprises methods and systems that use acoustic radiation pressure.

Provided herein are methods of splitting droplets containing magnetically responsive beads in a droplet actuator. A droplet actuator having a plurality of droplet operations electrodes configured to transport the droplet, and a magnetic field present at the droplet operations electrodes, is provided. The magnetically responsive beads in the droplet are immobilized using the magnetic field and the plurality of droplet operations electrodes are used to split the droplet into first and second droplets while the magnetically responsive beads remain substantially immobilized.

In one embodiment, the invention is to a sample metering device, comprising a sample holding chamber oriented between a sample entry port and a sample isolation unit and having a diluent introduction port disposed therebetween for introduction of a diluent into the sample holding chamber. The volume within the sample holding chamber between the diluent introduction port and the sample isolation unit defines a metered volume of a sample for analysis. In another embodiment, the invention is to an apparatus and method for rapid determination of analytes in liquid samples by various assays including immunoassays incorporating a sample dilution feature, preferably suitable for low range sample dilution, and preferably capable of being used in the point-of-care diagnostic field.

Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

In one embodiment, the invention is to a sample metering device, comprising a sample holding chamber oriented between a sample entry port and a sample extraction unit, wherein a portion of said extraction unit defines a metered volume of a sample. A diluent may be transported over and/or through the extraction unit to form a diluted sample for sample analysis. In another embodiment, the invention is to an apparatus and method for rapid determination of analytes in liquid samples by various assays including immunoassays incorporating a sample dilution feature, capable of being used in the point-of-care diagnostic field is provided. The devices and methods of the invention preferably are well-suited for high range sample dilution.

The invention provides a method of circulating magnetically responsive beads within a droplet in a droplet actuator. The invention also provides methods for splitting droplets. The invention, in one embodiment, makes use of a droplet actuator with top and bottom substrates, a plurality of magnetic fields respectively present proximate the top and bottom substrates, wherein at least one of the magnet fields is selectively alterable, and a plurality of droplet operations electrodes positioned along at least one of the top and bottom surfaces. A droplet is positioned between the top and bottom surfaces and at least one of the magnetic fields is selectively altered.

In one embodiment, the invention is to a sample metering device, comprising a sample holding chamber oriented between a sample entry port and a sample isolation unit and having a diluent introduction port disposed therebetween for introduction of a diluent into the sample holding chamber. The volume within the sample holding chamber between the diluent introduction port and the sample isolation unit defines a metered volume of a sample for analysis. In another embodiment, the invention is to an apparatus and method for rapid determination of analytes in liquid samples by various assays including immunoassays incorporating a sample dilution feature, preferably suitable for low range sample dilution, and preferably capable of being used in the point-of-care diagnostic field.