Methods for quantitative target detection and related devices and systems

1. A method to detect an endogenous target in a sample, the method comprising:

dividing the sample in a plurality of subsamples, each containing the endogenous target,

adding to the subsamples set quantities of non-endogenous target and/or analog thereof, the subsamples comprising a subsample with no non-endogenous target nor analog thereof added thereto;

detecting the added non-endogenous target or analog thereof in each subsample thus providing a set of detection signals comprising a detection signal related to the subsample with no non-endogenous target nor analog thereof added thereto;

subtracting a background signal from each detection signal to provide a set of net signals comprising a net signal related to the subsample with no non-endogenous target nor analog thereof added thereto;

providing a distribution of signal points, each signal point based on a net signal of the set of net signals, the signal points comprising a signal point related to the subsample with no non-endogenous target nor analog thereof added thereto, the distribution having a slope; and

determining the endogenous target concentration in the sample by dividing the amplitude of the signal point related to the subsample with no non-endogenous target nor analog thereof added thereto by the slope of the distribution.

2. The method of claim 1 , wherein the set quantities of the added non-endogenous target and/or analog thereof are determined on the basis of an expected concentration of the endogenous target to be detected.

3. The method of claim 1 , wherein the endogenous target comprises multiple targets and the detection of each target or multiple targets is performed in parallel or in series.

4. The method of claim 3 , wherein the detection of each endogenous target is performed with a panel of different labeled molecules specific for said each target, each labeled molecule producing a detection signal.

5. The method of claim 1 , wherein, before the dividing, the method comprises processing the sample to separate particles or portions thereof.

6. The method of claim 5 , wherein the processing is performed by head-on filtration or cross-flow filtration.

7. The method of claim 1 , wherein the sample is a biological sample and the target is a biomarker.

8. The method of claim 1 , wherein the set quantities of non-endogenous target and/or analog thereof are positioned in lyophilized form on a fluidic pathway of the subsamples from an input towards an area wherein detection is performed.

9. The method of claim 8 , wherein the set quantities of non-endogenous target and/or analog thereof are added to the subsamples by microfluidic metering techniques.

10. The method of claim 1 , wherein the detection is performed by immunoassay.