that this will be inadequate for some and excessive for others, but there is little else they can do, as it is not possible to tell who needs what. identification of risk factors, to help individualise treatment, is a big field in medicine. treatment generally the approach is to bring a cancer into remission first (absence of symptoms) and then try to eradicate the remaining cells (mrd). often the treatments needed to eradicate mrd differ from those used initially. this is an area of much research. it seems a sensible idea to aim to reduce or eradicate mrd. what is needed is evidence on which is the best method, and how well it works. this is emerging. treatments which specifically target mrd can include: intensive conventional treatment with more drugs, or a different combination of drugs stem cell transplant, e.g. marrow transplant. this allows more intensive chemotherapy to be given, and in addition the transplanted bone marrow may help eradicate the minimal residual disease immunotherapy monitoring the patient carefully for early signs of relapse. this is an area of active research in several countries. treatment with monoclonal antibodies which target cancer cells cancer vaccines areas of current research and controversies clinical usefulness of mrd tests it is important that doctors interpreting tests, base what they say on scientific evidence. if one visits hospital and gets tested for something - e.g. a blood count - most of the tests are used often, and have been done thousands or millions of times before, on many different people. the doctors reading the test results have a large body of evidence to interpret what the results mean. by contrast, mrd tests are new, and the diseases are uncommon. the tests have been done on relatively few people. consequently, there is less evidence available to guide doctors in interpreting the tests, or basing treatment decisions on them. in plain english, this means the doctors are likely to be very cautious, and rely more on other tests which they know and trust, than these, at least at present, while evidence is accumulating. method for testing, and when to test there are controversies about the best times to test, and the best test method to use. there are national and international approaches to standardize these. in childhood leukaemia and chronic myeloid leukaemia, there appears to be consensus emerging. is there such a thing as a safe level of mrd there is also controversy about whether mrd is always bad, inevitably causing relapse, or whether sometimes low levels are 'safe' and do not regrow. it is usually assumed that cancer cells inevitably grow and that if they are present disease usually develops. but there is some evidence from animal studies, that leukaemic cells can lie dormant for years in the body and do not regrow. for this reason, it may be that the goal of treating mrd may be to reduce it to a "safe" level - not to eradicate it completely. is mrd testing useful for all patients? some types of leukaemia are difficult to treat. in these, it is not clear how mrd testing would help. the patients may not do well on current treatment, but sometimes it is not clear what other treatment, if anything, might be better. there is thus an argument that as the test is not necessary: it might involve an additional procedure for the patient; it will contribute no useful information on treatment, it is not necessary. testing by hospitals and other labs where done mrd testing is not yet a routine test, nor is it carried out in all places. currently most mrd testing - in leukemia research - is done during clinical trials, and would be funded as part of that trial, for patients enrolled on the trial. the tests are specialised, so samples are usually sent to a central reference laboratory in each region or country. the tests are not done in most routine diagnostic labs, as they tend to be complex, and also would be used relatively infrequently. cost mrd testing is technically demanding and time-consuming; the tests are expensive, so are usually available only through specialist centres, as part of clinical trials. availability of testing at the time of writing (jan 2017), mrd testing is available in some clinical trials in the uk, europe, australia, china and the us. interpretation of test results most clinical tests used to guide treatment - e.g. even a simple blood count - have been done millions of times, and doctors can interpret the results confidently, based on this extensive previous knowledge. by contrast, mrd tests are new and have been carried out on relatively few people (a few thousand at most). researchers and doctors are still building the extensive database of knowledge needed to show what mrd tests mean. the consequence: unless a patient is enrolled on a trial which requires the test, clinicians tend to be somewhat cautious about requesting it, and cautious about interpreting the results. this is likely to change in future, as tests become more routine. resources general minimal residual disease. website. modern mrd detection technologies. july 2013. leukaemia research fund (united kingdom) children with leukaemia (united kingdom) janica lane; stephen h. wolinsky; schneider, stephen henry (2005). the patient from hell: how i worked with my doctors to get the best of modern medicine, and how you can too. cambridge, ma: da capo books. isbn 0-7382-1025-0. textbooks frei e, kufe dw, holland jf (2003). "part vii pediatric oncology, section 37: pediatric oncology: childhood acute lymphoblastic leukemia". cancer medicine 6. hamilton, ont: bc decker. pp. 141a. isbn 1-55009-213-8. frei e, kufe dw, holland jf (2003). "part vii pediatric oncology, section 37: pediatric oncology: neuroblastoma: the concept of risk-related therapy". cancer medicine 6. hamilton, ont: bc decker. pp. 142c. isbn 1-55009-213-8. frei e, kufe dw, holland jf (2003). "section 34: hematopoietic system: adult acute lymphocytic leukemia: evaluation of minimal residual disease". cancer medicine 6. hamilton, ont: bc decker. pp. 129. isbn 1-55009-213-8. research papers haferlach t, bacher u, kern w, schnittger s, haferlach c (jan 2008). "the diagnosis of bcr/abl-negative chronic myeloproliferative diseases (cmpd): a comprehensive approach based on morphology, cytogenetics, and molecular markers". ann hematol. 87 (1): 1–10. doi:10.1007/s00277-007-0403-6. pmc 2082654. pmid 17938925. schmitt c, balogh b, grundt a, et al. 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