Laboratory Testing at the End of Life in Patients With Cancer: A Systematic Review of Utilization, Costs, Clinical Utility, and Patient Burden.

BackgroundLaboratory tests can identify reversible causes of distress near the end of life, but how often they are ordered does not by itself show whether they improve care.ObjectiveTo synthesize evidence on laboratory testing near the end of life in cancer, including utilization, costs, clinical utility, patient burden, and relationships with palliative care and advance care planning.MethodsWe conducted a PRISMA 2020 systematic review registered in PROSPERO (CRD420261493528). PubMed, Virtual Health Library, SciELO, Embase, CINAHL, and Web of Science were searched from database inception through September 8, 2026, supplemented by reference-list and citation tracking. Two reviewers screened studies and resolved disagreements by consensus. Joanna Briggs Institute (JBI) tools informed methodological appraisal, and findings were synthesized narratively.ResultsOf 2667 records, 35 studies reported in 42 publications were included. Reported testing proportions ranged from 68 to 97% across end-of-life settings, although outcome definitions and units of analysis varied. Longitudinal studies in breast and gynecologic cancer showed increasing use as death approached. Associations with palliative care services varied by model and setting, whereas timely advance care planning was more consistently associated with lower utilization. Hospice and palliative models often reported lower laboratory use or costs. Few studies linked test results to management changes, symptom benefit, or patient experience.ConclusionsLaboratory testing is common near the end of life in cancer, but evidence is stronger for patterns of use and cost than for patient benefit. Testing decisions should be guided by a clear clinical question, a plausible effect on management, and the patient's goals of care.