One of the major clinical challenges in individualizing a chemotherapy dose regime is that the physician has no information about how the drug is eliminated by the patient at the time of administration. The initial dose given to a patient is often determined by the patient's body surface area which can then be adjusted by observational factors or supplemental patient descriptors. Although widely used, body surface area-based dosing does not correlate with plasma drug concentrations in most chemotherapies. There can be as much as a 10-fold difference in the plasma concentrations of chemotherapeutics between patients that are given the same body surface area derived dose. Drug clearance rates can also have a 2-to 10-fold difference between similar patients. These differences in inter-patient pharmacokinetics can have significant effects on patient outcomes as well as short-term side effects . As an example of possible side effects, Doxorubicin (DOX), one of the most commonly used drugs in pediatric cancer treatment, is commonly observed to cause dose-dependent bone marrow suppression (short-term) and cardiotoxicity (long-term). Physicians rely on observational methods to make dose adjustments and reduce chemotherapy doses based on the severity of side effects. However, these cytotoxic drugs have a very narrow therapeutic window where the maximum tolerable dose for that patient and the dose that has therapeutic effect on the tumor are very close. Excessive dose reductions to mitigate side effects may result in underdosing, compromising tumor control. The effectiveness of chemotherapy dosing is typically only assessed 6 to 8 weeks after treatment initiation by evaluating tumor size. If tumor progression is observed, physicians may switch to a different drug. These decisions are made without knowing the patient's pharmacokinetics, leaving it unclear if treatment failed due to insufficient drug exposure or tumor resistance. This observational approach has inherent delays that can allow tumor progression. This is particularly true for the clinical use of DOX. DOX has a very narrow therapeutic window and its main metabolite, which is a major concern for toxic side effects, is doxorubicinol (DOL). Being able to determine the concentration of DOX and DOL in a patient's blood at various time points after first infusion would be a great benefit to the medical community. This also applies to the administration of Doxil, the widely used liposomal form of DOX. Therapeutic drug monitoring (TDM) looks to provide information about the concentration of the drug in plasma over time to determine elimination rates for a specific patient. This information can help the physicians adjust dosing to achieve plasma concentration levels that are more likely to result in positive clinical outcomes while reducing side effects . One major challenge with TDM is that it is currently a time-consuming process, requiring specialized equipment that are expensive and labor intensive. These challenges prevent TDM from being translated into the clinical setting. In consequence, TDM for chemotherapy is primary deployed in smaller scale clinical trials in partnership with academic laboratories. Currently, the gold standard method to quantify circulating drug concentrations is the use of high pressure liquid chromatography (HPLC) techniques. Although a time-tested method in the analytical chemistry laboratory setting, the application of HPLC to the clinical setting introduces logistical complexity that can compromise the reliability of the measured DOX concentrations. The current method to address these challenges is to have a dedicated research staff immediately evaluate the sample. This involves spinning down the red blood cells to produce plasma. Typically, plasma samples are frozen and then sent on dry ice (-80C) to a centralized facility, where drugs are extracted from the plasma using an organic phase partitioning method, and the drug content is then quantified by high pressure liquid chromatography (HPLC) techniques. The HPLC equipment requires a high level of maintenance and specialized training to operate reliably, notably to maintain consistent column conditions and variable gradients of solvents that are necessary to achieve the required separation between the target drug, its metabolites and other compounds and residues. In consequence, wide-scale TDM-led dose personalization is hindered by the logistical complexity, poor scalability due to lack of trained personal to handle and analyze the blood samples quickly, and sample handling inconsistencies involved in having to rely on centralized HPLC services. This incurs significant pre-analytical error, especially for anthracyclines, such as DOX, which are susceptible to degradation in the presence of red blood cells and thus poorly amenable to the processing delays associated with a centralized TDM process. Although HPLC is a reliable method in the laboratory setting, these technical factors prevent HPLC from being widely used in the clinical setting.