One Sample, Several Readings: Telling How Firm a Blood-Test Cancer Call Is, Using the Test's Own Processing Settings

A blood test for early cancer reads the DNA fragments in one sample and gives a score, but the score does not say how firm the call is, especially for samples near the cut-off. This concept note describes a simple check that can sit on top of any such test. From the sequencing data already stored, the computer makes two to four versions by moving only the test's own processing settings, inside the range that the maker and the laboratory's validation permit. The same program, unchanged, reads every version. One number, the spread value, shows how much the call depends on a setting, and it is inversely proportional to the size of the leading eigenvalue, so a wide spread means the call is near a tipping point. Three calm states follow: Steady, Watch and Look closer. A computer-decided shunting action then acts without waiting for a person. It moves the samples that need care to the front of the second-review list, while all other samples carry on and nothing is stopped. Only one program and one sample are used, so the spread has a single cause: the processing settings. The note describes the idea and the steps. No results on real samples are given. Patent pending. Suggested keywords: liquid biopsy; multi-cancer early detection; cell-free DNA; early warning; uncertainty; borderline calls; second review