Acute Leukemia - MRD Panel (MRD & Relapse)

MRD-positive means sensitive tests detect small numbers of cancer cells after treatment. It does not equal clinical relapse but indicates a higher risk of eventual relapse and often leads to closer monitoring or additional therapy. Some MRD-positive patients remain disease-free with further treatment, while others progress to relapse; interpretation depends on disease type, MRD level and timing.

MRD (minimal or measurable residual disease) in acute leukemia is the small number of cancer cells remaining after treatment that are undetectable by standard microscopy. Highly sensitive techniques—flow cytometry, PCR, or next‑generation sequencing—identify MRD. Its detection predicts higher relapse risk and informs risk stratification and treatment decisions, such as therapy intensification, targeted agents, or stem cell transplant.

A relapse of acute leukemia is the return of leukemic cells after a period of remission, identified by rising abnormal blood counts, increased bone marrow blasts, or recurring symptoms. Relapse may occur in the marrow or at extramedullary sites. Prognosis and treatment—additional chemotherapy, targeted agents, immunotherapy, or stem-cell transplant—depend on leukemia type, time to relapse, and patient factors.

MRD‑positive means that sensitive laboratory tests (flow cytometry, PCR or next‑generation sequencing) detect residual cancer cells after treatment. Whether a result is MRD‑positive depends on assay sensitivity and the disease; commonly cited thresholds are ≥10⁻⁴ (one cancer cell per 10,000) or more stringent limits (10⁻⁵–10⁻⁶). MRD positivity signals higher relapse risk and may prompt more treatment or closer monitoring.

MRD‑negative means sensitive tests find no detectable cancer cells. It indicates a deep response and is strongly associated with remission and better prognosis, but it doesn’t guarantee cure—very small numbers of cells can remain below test detection and later cause relapse. MRD status helps guide treatment and monitoring decisions; continued follow‑up is needed even when MRD is negative.

Remission is a period when disease signs and symptoms reduce or disappear—partial or complete—without necessarily meaning cure. It can be temporary or sustained. Relapse is the return or worsening of disease after a period of improvement or remission; symptoms reappear or escalate. In other words, remission = symptom improvement/absence; relapse = recurrence or flare-up of the condition.