A circulating variant with an uncertain source

A fictional patient undergoing plasma sequencing has a known solid tumor. The assay detects a variant in a gene that is also commonly encountered in clonal hematopoiesis, but no paired leukocyte result or matched tumor sequence has yet been reviewed. A trainee calls the finding proven CHIP based only on the gene name and a small variant allele fraction, then discards it without recording the uncertainty. The responsible team asks whether the assay result alone identifies the cellular source. The case supplies no evidence that the variant is definitely from either tissue compartment. It tests cautious attribution and the purpose of paired or confirmatory assessment.