A system comprising a microfluidic cartridge and a diagnostic apparatus for amplifying and carrying out diagnostic analyses on nucleotides from biological samples, wherein: the microfluidic cartridge is a disposable multi-lane microfluidic cartridge containing sample lanes in parallel, the microfluidic cartridge including first, second and third layers that together define a plurality of microfluidic networks, each of the multiple sample lanes having an independently configured microfluidic network, each network having a PCR reactor configured to carry out PCR amplification of nucleotides in a sample, the microfluidic cartridge further comprising a window arranged above the PCR reactor that permits optical detection of fluorescence by the diagnostic apparatus when a detector of the diagnostic apparatus is situated above the window; and the diagnostic apparatus is configured for carrying out real-time PCR on a number of samples in the cartridge and comprises: a reusable instrument platform to actuate on-cartridge operations, detect and analyze the products of PCR amplification in each of the sample lanes separately; the detector for monitoring fluorescence from biochemical reactions; a bay configured to selectively receive the microfluidic cartridge; and, at least one heat source positioned in the bay and coupled to a processor, wherein the at least one heat source is configured to heat individual sample lanes in the microfluidic cartridge, the processor being configured to control application of heat to the individual sample lanes separately, wherein the at least one heat source is a contact heat source, wherein the contact heat source is configured at the bay to be thermally coupled to one or more distinct locations of the microfluidic cartridge received in the bay, whereby the distinct locations are selectively heated, wherein at least one additional contact heat source is included, wherein the contact heat sources are each configured at the bay to be independently thermally coupled to a different distinct location in the microfluidic cartridge received in the bay, whereby the distinct locations are independently heated, and wherein each PCR reactor is a microfluidic channel that is heated through a series of cycles to carry out amplification of nucleotides in the biological sample. the microfluidic cartridge is a disposable multi-lane microfluidic cartridge containing sample lanes in parallel, the microfluidic cartridge including first, second and third layers that together define a plurality of microfluidic networks, each of the multiple sample lanes having an independently configured microfluidic network, each network having a PCR reactor configured to carry out PCR amplification of nucleotides in a sample, the microfluidic cartridge further comprising a window arranged above the PCR reactor that permits optical detection of fluorescence by the diagnostic apparatus when a detector of the diagnostic apparatus is situated above the window; and the diagnostic apparatus is configured for carrying out real-time PCR on a number of samples in the cartridge and comprises: a reusable instrument platform to actuate on-cartridge operations, detect and analyze the products of PCR amplification in each of the sample lanes separately; the detector for monitoring fluorescence from biochemical reactions; a bay configured to selectively receive the microfluidic cartridge; and, at least one heat source positioned in the bay and coupled to a processor, a reusable instrument platform to actuate on-cartridge operations, detect and analyze the products of PCR amplification in each of the sample lanes separately; the detector for monitoring fluorescence from biochemical reactions; a bay configured to selectively receive the microfluidic cartridge; and, at least one heat source positioned in the bay and coupled to a processor, wherein the at least one heat source is configured to heat individual sample lanes in the microfluidic cartridge, the processor being configured to control application of heat to the individual sample lanes separately, wherein the at least one heat source is a contact heat source, wherein the contact heat source is configured at the bay to be thermally coupled to one or more distinct locations of the microfluidic cartridge received in the bay, whereby the distinct locations are selectively heated, wherein at least one additional contact heat source is included, wherein the contact heat sources are each configured at the bay to be independently thermally coupled to a different distinct location in the microfluidic cartridge received in the bay, whereby the distinct locations are independently heated, and wherein each PCR reactor is a microfluidic channel that is heated through a series of cycles to carry out amplification of nucleotides in the biological sample.