Despite its advantages, liquid biopsy has real limitations that patients and clinicians need to understand:

*Sensitivity varies by cancer type and stage: Early-stage cancers or tumours that do not shed much genetic material into the bloodstream may not produce a detectable signal, leading to false-negative results
*It cannot always tell where the cancer is located in the body, unlike a tissue biopsy or imaging scan
It may miss mutations present only in certain parts of a tumour if those regions are not shedding material into the blood at detectable levels, an issue related to tumour heterogeneity
*Results can be affected by “clonal haematopoiesis,” a condition where blood-forming cells develop mutations unrelated to the cancer, which can sometimes be mistaken for tumour-derived mutations
*It is generally used alongside tissue biopsy and imaging rather than as a complete replacement, especially at the time of initial cancer diagnosis, when a full pathological confirmation from tissue is still considered the standard
*Cost and availability can vary, and not all liquid biopsy tests are validated for every cancer type or clinical situation