Methods for isolating a target analyte from a heterogeneous sample

A method for isolating pathogen from a heterogeneous sample, the method comprising:

• providing a vessel that contains a heterogeneous sample comprising pathogen, the vessel being coupled to a microfluidic device that comprises a channel and a magnet;
• introducing to the sample a cocktail comprising a plurality of sets of magnetic particles, members of different sets being conjugated to different antibodies that are specific for different pathogen, wherein at least two of the sets are provided at different concentrations, thereby forming a mixture;
• flowing the mixture from the vessel through a channel in the microfluidic device and toward a magnet in the microfluidic device;
• and
• separating particle bound pathogen from other components in the sample by using the magnet to retain pathogen bound to magnetic particles while unbound sample components are not retained by the magnet.